1. NASA Mission Helps Solve a Mystery: Why Are Some Asteroid Surfaces Rocky?

    October 23, 2021 -

     Summary: Using data from NASA’s OSIRIS-REx mission, a University of Arizona-led team of scientists concluded that asteroids with highly porous rocks like Bennu should lack fine-grained material on their surfaces.

    Scientists thought Bennu’s surface was like a sandy beach, abundant in fine sand and pebbles, which would have been perfect for collecting samples. Past telescope observations from Earth orbit had suggested the presence of large swaths of fine-grained material smaller than a few centimeters called fine regolith.

    But when NASA’s OSIRIS-REx mission arrived at Bennu in late 2018, the mission saw a surface covered in boulders. The mysterious lack of fine regolith became even more surprising when mission scientists observed evidence of processes potentially capable of grinding boulders into fine regolith.

    New research, published in Nature and led by Saverio Cambioni, of the University of Arizona, used machine learning and surface temperature data to solve the mystery. Cambioni conducted the research at the university’s Lunar and Planetary Laboratory. He and his colleagues ultimately found that Bennu’s highly porous rocks are responsible for the surface’s surprising lack of fine regolith.

    “The ‘REx’ in OSIRIS-REx stands for Regolith Explorer, so mapping and characterizing the surface of the asteroid was a main goal,” said study co-author and OSIRIS-REx Principal Investigator Dante Lauretta, a Regents Professor of Planetary Sciences at the University of Arizona. “The spacecraft collected very high-resolution data for Bennu’s entire surface, which was down to 3 millimeters per pixel at some locations. Beyond scientific interest, the lack of fine regolith became a challenge for the mission itself, because the spacecraft was designed to collect such material.”

    A Rocky Start and Solid Answers

    “When the first images of Bennu came in, we noted some areas where the resolution was not high enough to see whether there were small rocks or fine regolith. We started using our machine learning approach to distinguish fine regolith from rocks using thermal emission (infrared) data,” Cambioni said.

    This mosaic of Bennu was created using observations made by NASA’s OSIRIS-REx spacecraft that was in close proximity to the asteroid for over two years. Credit: NASA/Goddard/University of Arizona

    The thermal emission from fine regolith is different from that of larger rocks, because the size of its particles controls the former, while the latter is controlled by rock porosity. The team first built a library of thermal emissions associated with fine regolith mixed in different proportions with rocks of various porosity. Next, they used machine-learning techniques to teach a computer how to “connect the dots” between the examples, Cambioni said. They analyzed 122 areas on the surface of Bennu, that were observed both during the day and the night.

    “Only machine learning could efficiently explore a dataset this large,” Cambioni said.

    Cambioni and his collaborators found something surprising when the data analysis was completed: the fine regolith was not randomly distributed on Bennu. Instead, it was up to several tens of percent in those very few areas where rocks are non-porous, and systematically lower where rocks have higher porosity, which is most of the surface.

    The team concluded that very little fine regolith is produced from Bennu’s highly porous rocks because these are compressed rather than fragmented by meteoroid impacts. Like a sponge, the voids within rocks cushion the blow from incoming meteoroids. These findings are also in agreement with laboratory experiments from other research groups.

    “Basically, a big part of the energy of the impact goes into crushing the pores restricting the fragmentation of the rocks and the production of new fine regolith,” said study co-author Chrysa Avdellidou, a postdoctoral researcher at the French National Centre for Scientific Research (CNRS) – Lagrange Laboratory of the Côte d’Azur Observatory and University in France. Additionally, Cambioni and colleagues showed that cracking caused by the heating and cooling of Bennu’s rocks as the asteroid rotates through day and night proceeds more slowly in porous rocks than in denser rocks, further frustrating the production of fine regolith.

    “When OSIRIS-REx delivers its sample of Bennu (to Earth) in September 2023, scientists will be able to study the samples in detail,” said Jason Dworkin, OSIRIS-REx project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This includes testing the physical properties of the rocks to verify this study.”

    Other missions have evidence to support the team’s findings. The Japan Aerospace and Exploration Agency (JAXA) Hayabusa2 mission to Ryugu, a carbonaceous asteroid like Bennu, found that Ryugu also lacks fine regolith and has high-porosity rocks. Conversely, JAXA’s Hayabusa mission in 2005 revealed abundant fine regolith on the surface of asteroid Itokawa, an S-type asteroid with rocks of a different composition than Bennu and Ryugu. A previous study also from Cambioni and colleagues provided evidence that its rocks are less porous than Bennu’s and Ryugu’s using observations from Earth.

    “For decades, astronomers disputed that small, near-Earth asteroids could have bare-rock surfaces,” said study co-author Marco Delbo, research director with CNRS, also at the Lagrange Laboratory. “The most indisputable evidence that these small asteroids could have substantial fine regolith emerged when spacecraft visited S-type asteroids Eros and Itokawa in the 2000s and found fine regolith on their surfaces.”

    The team predicts that large swaths of fine regolith should be uncommon on carbonaceous asteroids, the most common of all asteroid types observed, and which the team expects to have high-porosity rocks like Bennu. By contrast, they predict terrains rich in fine regolith to be common on S-type asteroids, the second-most populous type of asteroids observed in the solar system, which they expect to have denser, less porous rocks than carbonaceous asteroids.

    “This is an important piece in the puzzle of what drives the diversity of asteroids’ surfaces,” Cambioni said. “Asteroids are thought to be relics of the early solar system, so understanding the evolution they have undergone in time is crucial to comprehend how the solar system formed and evolved. Now that we know this fundamental difference between carbonaceous and S-type asteroids, future teams can better prepare sample collection missions depending on the nature of the target asteroid.”

    Cambioni is continuing his research on planetary diversity as a distinguished postdoctoral fellow in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology.

    The University of Arizona leads the OSIRIS-REx science team and the mission’s science observation planning and data processing. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate at NASA Headquarters in Washington, D.C.

    Writer: Mikayla Mace Kelley
    The University of Arizona

    Related Links:

    University of Arizona Press Release: Highly Porous Rocks Responsible for Bennu’s Surprisingly Craggy Surface

    Nature: Fine-regolith production on asteroids controlled by rock porosity

     

  2. NASA Spacecraft Provides Insight into Asteroid Bennu’s Future Orbit

    August 11, 2021 -

    In a study released Wednesday, NASA researchers used precision-tracking data from the agency’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft to better understand movements of the potentially hazardous asteroid Bennu through the year 2300, significantly reducing uncertainties related to its future orbit, and improving scientists’ ability to determine the total impact probability and predict orbits of other asteroids.

    The study, titled “Ephemeris and hazard assessment for near-Earth asteroid (101955) Bennu based on OSIRIS-REx data,” was published in the journal Icarus.

    “NASA’s Planetary Defense mission is to find and monitor asteroids and comets that can come near Earth and may pose a hazard to our planet,” said Kelly Fast, program manager for the Near-Earth Object Observations Program at NASA Headquarters in Washington. “We carry out this endeavor through continuing astronomical surveys that collect data to discover previously unknown objects and refine our orbital models for them. The OSIRIS-REx mission has provided an extraordinary opportunity to refine and test these models, helping us better predict where Bennu will be when it makes its close approach to Earth more than a century from now.”

    In 2135, asteroid Bennu will make a close approach with Earth. Although the near-Earth object will not pose a danger to our planet at that time, scientists must understand Bennu’s exact trajectory during that encounter in order to predict how Earth’s gravity will alter the asteroid’s path around the Sun – and affect the hazard of Earth impact.

    Using NASA’s Deep Space Network and state-of-the-art computer models, scientists were able to significantly shrink uncertainties in Bennu’s orbit, determining its total impact probability through the year 2300 is about 1 in 1,750 (or 0.057%). The researchers were also able to identify Sept. 24, 2182, as the most significant single date in terms of a potential impact, with an impact probability of 1 in 2,700 (or about 0.037%).

    Although the chances of it hitting Earth are very low, Bennu remains one of the two most hazardous known asteroids in our solar system, along with another asteroid called 1950 DA.

    Before leaving Bennu May 10, 2021, OSIRIS-REx spent more than two years in close proximity to the asteroid, gathering information about its size (it is about one-third of a mile, or 500 meters, wide), shape, mass, and composition, while monitoring its spin and orbital trajectory. The spacecraft also scooped up a sample of rock and dust from the asteroid’s surface, which it will deliver to Earth on Sept. 24, 2023, for further scientific investigation.

    “The OSIRIS-REx data give us so much more precise information, we can test the limits of our models and calculate the future trajectory of Bennu to a very high degree of certainty through 2135,” said study lead Davide Farnocchia, of the Center for Near Earth Object Studies (CNEOS), which is managed by NASA’s Jet Propulsion Laboratory in Southern California. “We’ve never modeled an asteroid’s trajectory to this precision before.”

    This mosaic of Bennu was created using observations made by NASA’s OSIRIS-REx spacecraft that was in close proximity to the asteroid for over two years. Credit: NASA/Goddard/University of Arizona

    Gravitational keyholes

    The precision measurements on Bennu help to better determine how the asteroid’s orbit will evolve over time and whether it will pass through a “gravitational keyhole” during its 2135 close approach. These keyholes are areas in space that would set Bennu on a path toward a future impact with Earth if the asteroid were to pass through them at certain times, due to the effect of Earth’s gravitational pull.

    To calculate exactly where the asteroid will be during its 2135 close approach – and whether it might pass through a gravitational keyhole – Farnocchia and his team evaluated various types of small forces that may affect the asteroid as it orbits the Sun. Even the smallest force can significantly deflect its orbital path over time, causing it to pass through or completely miss a keyhole.

    Among those forces, the Sun’s heat plays a crucial role. As an asteroid travels around the Sun, sunlight heats up its dayside. Because the asteroid spins, the heated surface will rotate away and cool down when it enters the nightside. As it cools, the surface releases infrared energy, which generates a small amount of thrust on the asteroid – a phenomenon called the Yarkovsky effect. Over short timeframes, this thrust is minuscule, but over long periods, the effect on the asteroid’s position builds up and can play a significant role in changing an asteroid’s path.

    “The Yarkovsky effect will act on all asteroids of all sizes, and while it has been measured for a small fraction of the asteroid population from afar, OSIRIS-REx gave us the first opportunity to measure it in detail as Bennu travelled around the Sun,” said Steve Chesley, senior research scientist at JPL and study co-investigator. “The effect on Bennu is equivalent to the weight of three grapes constantly acting on the asteroid – tiny, yes, but significant when determining Bennu’s future impact chances over the decades and centuries to come.”

    The team considered many other perturbing forces as well, including the gravity of the Sun, the planets, their moons, and more than 300 other asteroids, the drag caused by interplanetary dust, the pressure of the solar wind, and Bennu’s particle-ejection events. The researchers even evaluated the force OSIRIS-REx exerted when performing its Touch-And-Go (TAG) sample collection event Oct. 20, 2020, to see if it might have slightly altered Bennu’s orbit, ultimately confirming previous estimates that the TAG event had a negligible effect.

    “The force exerted on Bennu’s surface during the TAG event were tiny even in comparison to the effects of other small forces considered,” said Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “TAG did not alter Bennu’s likelihood of impacting Earth.”

    Tiny risk, huge gain

    Although a 0.057% impact probability through the year 2300 and an impact probability of 0.037% on Sept. 24, 2182, are low, this study highlights the crucial role that OSIRIS-REx operations played in precisely characterizing Bennu’s orbit.

    “The orbital data from this mission helped us better appreciate Bennu’s impact chances over the next couple of centuries and our overall understanding of potentially hazardous asteroids – an incredible result,” said Dante Lauretta, OSIRIS-REx principal investigator and professor at the University of Arizona. “The spacecraft is now returning home, carrying a precious sample from this fascinating ancient object that will help us better understand not only the history of the solar system but also the role of sunlight in altering Bennu’s orbit since we will measure the asteroid’s thermal properties at unprecedented scales in laboratories on Earth.”

    More about OSIRIS-REx

    Goddard provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Lauretta is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space Systems in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace in Tempe, Arizona are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers ProgramNASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the agency’s New Frontiers Program for the agency’s Science Mission Directorate in Washington.

    For more information about the OSIRIS-REx mission, visit:

    https://www.nasa.gov/osiris-rex

    To view the images discussed during today’s media teleconference, visit:

    https://svs.gsfc.nasa.gov/13906

    More about NASA’s CNEOS and Planetary Defense Coordination Office

    CNEOS computes high-precision orbits for near-Earth objects (NEOs) in support of NASA’s Planetary Defense Coordination Office, to help precisely characterize every NEO’s orbit to improve long-term hazard assessments.

    More information about CNEOS, asteroids, and near-Earth objects can be found at:

    https://cneos.jpl.nasa.gov

    For more information about NASA’s Planetary Defense Coordination Office, visit:

    https://www.nasa.gov/planetarydefense

    For asteroid and comet news and updates, follow @AsteroidWatch on Twitter.

    Karen Fox / Alana Johnson / Josh Handal
    NASA Headquarters, Washington
    301-286-6284 / 202-358-1501 / 202-358-2307
    karen.c.fox@nasa.gov / alana.r.johnson@nasa.gov / Joshua.a.handal@nasa.gov

    Ian J. O’Neill
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-2649
    ian.j.oneill@jpl.nasa.gov

    Rani Gran
    Goddard Space Flight Center, Greenbelt, Md.
    301-332-6975
    rani.gran@jpl.nasa.gov

  3. NASA’s “Tour of Asteroid Bennu” Selected for Prestigious Computer Graphics Film Festival

    August 10, 2021 -

    It’s hard to imagine what the surface of asteroid Bennu might look like – it’s shortest distance from Earth still 250,000 miles away – but the video “Tour of Asteroid Bennu” brings us on a journey to see this landscape up close.

    On August 9 and 11, 2021, the video produced at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will be featured in the SIGGRAPH Computer Animation Festival Electronic Theater – a high honor for those in the graphic visualization field.

    “We’re going up against the best of the best in the graphics industry right now,” said Kel Elkins, lead data visualizer for the project. “And it’s very exciting when something that we create, especially something data driven like this can compete and get accepted on the same level as these other pieces.”

    The Electronic Theater, often likened to the Academy Awards for graphics, highlights empowering and inspirational short video stories created through the use of computer graphics and interactive techniques. “Tour of Asteroid Bennu” will be recognized alongside 36 other short videos in this year’s SIGGRAPH viewing.

    Thanks to laser altimetry data and high-resolution imagery from NASA’s OSIRIS-REx spacecraft, we can take a tour of asteroid Bennu’s remarkable terrain.

    Credits: NASA’s Goddard Space Flight Center This video is public domain and can be downloaded from the Scientific Visualization Studio.

    The story of this video begins in March 2020, just at the start of the pandemic.

    “I remember taking breaks, my lunchtime walk around my neighborhood, and sort of thinking up some shots, like how we would first approach the asteroid,” said Dan Gallagher, producer and writer at NASA’s Goddard Space Flight Center.

    The video, which now has just under one million views on YouTube, utilizes advanced graphics techniques to portray the close-to-home asteroid.

    Unlike the other videos being featured at SIGGRAPH, Gallagher and Elkins used actual scientific data from NASA’s OSIRIS-REx spacecraft to create “Tour of Asteroid Bennu.” OSIRIS-REx, which launched on September 6, 2016, reached the asteroid in 2018 and gathered imagery, lidar, laser ranging, data, and other forms of data while in orbit. The spacecraft even briefly touched down on the asteroid to take a sample in October 2020.

    Depicted by an orange loop around the asteroid, the beginning of the video highlights the location of the spacecraft while in orbit, which is based on actual mission data. The 3D model of the asteroid comes primarily from lidar data, but as the camera takes the viewer in closer to Bennu, the model also incorporates global image mosaics and global brightness maps.

    “We had this idea to do for Bennu what Ernie Wright had done in his Tour of the Moon, which was to take terrain data, and high-resolution imagery and make a really awesome flyover of Bennu and put the camera down as close as we could to the surface and fly it over some of the new features,” Gallagher said.

    The tour of the asteroid covers six sites in depth, stating the name of each site as well as giving a 3D view of the surroundings. According to a behind-the-scenes video diving into the making of “Tour of Asteroid Bennu,” the model of the asteroid began as a low-resolution polygon model, limiting how close the camera could get to the surface. As the OSIRIS-REx mission continued, more data was collected, until the model was composed of five-centimeter resolution tiles.

    “Every time we would get new high-resolution models of the asteroid, we would try pushing the camera in closer and closer in those regions,” Elkins said.

    When zooming into the close up locations or boulders, there are individual tiles with varying resolutions that had to have been combined to keep the levels of detail as the camera is getting closer. Elkins meticulously selected the individual tiles depending on where the camera was looking to stitch together a finalized view of the model at varying vantage points.

    Other videos accepted by SIGGRAPH are artists’ renditions, but with the use of scientific data to create a graphical representation come some limitations. Stitching tiles together leaves some unavoidable imperfections or holes, compared to an artistic assembly.

    “That’s why we’re super excited that our data visualizations were pulled into the same level as some of these other pieces,” Elkins said.

    With the electronic theater viewing date drawing closer, Gallagher reflects on the precedent that “Tour of Asteroid Bennu” sets.

    “I think there’s a big demand in the public.” Gallagher said. “People love exploration, they love novelty. This is a whole new world and it’s a world that can be hard to really fully appreciate in two dimensional photographs. I think that really reflects the hunger that people have for exploration, and it’s a way to explore Bennu remotely through technology, so it’s very exciting to see it reach that level.”

    On August 9 and 11, 2021, “Tour of Asteroid Bennu” will be featured in the SIGGRAPH awards electronic theater. Producer Dan Gallagher and data visualizer Kel Elkins discuss the making of the video, and how data-driven animation is enabling viewers to explore new worlds like Bennu.

    Credits: NASA’s Goddard Space Flight Center

    Erica McNamee,
    NASA’s Goddard Space Flight Center

  4. NASA’s OSIRIS-REx Spacecraft Heads for Earth with Asteroid Sample

    May 12, 2021 -

    After nearly five years in space, NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft is on its way back to Earth with an abundance of rocks and dust from the near-Earth asteroid Bennu.

    This illustration shows the OSIRIS-REx spacecraft departing asteroid Bennu to begin its two-year journey back to Earth. Credit: NASA/Goddard/University of Arizona

    On Monday, May 10, at 4:23 p.m. EDT the spacecraft fired its main engines full throttle for seven minutes – its most significant maneuver since it arrived at Bennu in 2018. This burn thrust the spacecraft away from the asteroid at 600 miles per hour (nearly 1,000 kilometers per hour), setting it on a 2.5-year cruise towards Earth.

    After releasing the sample capsule, OSIRIS-REx will have completed its primary mission. It will fire its engines to fly by Earth safely, putting it on a trajectory to circle the sun inside of Venus’ orbit.

    After orbiting the Sun twice, the OSIRIS-REx spacecraft is due to reach Earth Sept. 24, 2023. Upon return, the capsule containing pieces of Bennu will separate from the rest of the spacecraft and enter Earth’s atmosphere. The capsule will parachute to the Utah Test and Training Range in Utah’s West Desert, where scientists will be waiting to retrieve it.

    “OSIRIS-REx’s many accomplishments demonstrated the daring and innovate way in which exploration unfolds in real time,” said Thomas Zurbuchen, associate administrator for science at NASA Headquarters. “The team rose to the challenge, and now we have a primordial piece of our solar system headed back to Earth where many generations of researchers can unlock its secrets.”

    To realize the mission’s multi-year plan, a dozen navigation engineers made calculations and wrote computer code to instruct the spacecraft when and how to push itself away from Bennu. After departing from Bennu, getting the sample to Earth safely is the team’s next critical goal. This includes planning future maneuvers to keep the spacecraft on course throughout its journey.

    “Our whole mindset has been, ‘Where are we in space relative to Bennu?’” said Mike Moreau, OSIRIS-REx deputy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Now our mindset has shifted to ‘Where is the spacecraft in relation to Earth?’”

    The navigation cameras that helped orient the spacecraft in relation to Bennu were turned off April 9, after snapping their last images of the asteroid. With Bennu in the rearview mirror, engineers are using NASA’s Deep Space Network of global spacecraft communications facilities to steer the OSIRIS-REx by sending it radio signals. By measuring the frequency of the waves returned from the spacecraft transponder, engineers can tell how fast OSIRIS-REx is moving. Engineers measure how long it takes for radio signals to get from the spacecraft back to Earth in order to determine its location.

    Exceeding Mission Expectations

    The May 10 departure date was precisely timed based on the alignment of Bennu with Earth. The goal of the return maneuver is to get the spacecraft within about 6,000 miles  (approximately 10,000 kilometers) of Earth in September 2023. Although OSIRIS-REx still has plenty of fuel remaining, the team is trying to preserve as much as possible for a potential extended mission to another asteroid after returning the sample capsule to Earth. The team will investigate the feasibility of such a mission this summer.

    The spacecraft’s course will be determined mainly by the Sun’s gravity, but engineers will need to occasionally make small course adjustments via engine burns.

    “We need to do regular corrections to bring the trajectory increasingly closer to Earth’s atmosphere for the sample release, and to account for small errors that might have accumulated since the last burn,” said Peter Antreasian, OSIRIS-REx navigation lead at KinetX Aerospace, which is based in Simi Valley, California.

    The team will perform course adjustments a few weeks prior to Earth re-entry in order to precisely target the location and angle for the sample capsule’s release into Earth’s atmosphere. Coming in too low could cause the capsule to bounce out of the atmosphere like a pebble skipping off a lake; too high and the capsule could burn up due to friction and heat from the atmosphere. If OSIRIS-REx fails to release the capsule, the team has a backup plan to divert it away from Earth and try again in 2025.

    “There’s a lot of emotion within the team about departure,” Moreau said. “I think everyone has a great sense of accomplishment, because we faced all these daunting tasks and were able to accomplish all the objectives thrown at us. But there’s also some nostalgia and disappointment that this part of the mission is coming to an end.”

    OSIRIS-REx exceeded many expectations. Most recently, in the midst of a global pandemic, the team flawlessly executed the most mission’s critical operation, collecting more than 2 ounces (60 grams) of soil from Bennu’s surface.

    Leading up to sample collection, a number of surprises kept the team on its toes. For example, a week after the spacecraft entered its first orbit around Bennu, on Dec. 31, 2018, the team realized that the asteroid was releasing small pieces of rock into space.

    “We had to scramble to verify that the small particles being ejected from the surface did not present a hazard to the spacecraft,” Moreau said.

    Upon arrival at the asteroid, team members also were astonished to find that Bennu is littered with boulders.

    “We really had this idea that we were arriving on an asteroid with open real estate,” said Heather Enos, OSIRIS-REx deputy principal investigator, based at the University of Arizona, Tucson. “The reality was a big shocker.”

    To overcome the extreme and unexpected ruggedness of Bennu’s surface, engineers had to quickly develop a more accurate navigation technique to target smaller-than-expected sites for sample collection.

    The OSIRIS-REx mission was instrumental in both confirming and refuting several scientific findings. Among those confirmed was a technique that used observations from Earth to predict that the minerals on the asteroid would be carbon-rich and show signs of ancient water. One finding that proved unsuccessful was that Bennu would have a smooth surface, which scientists predicted by measuring how much heat radiated off its surface.

    Scientists will use the information gleaned from Bennu to refine theoretical models and improve future predictions.

    “This mission emphasizes why we have to do science and exploration in multiple ways – both from Earth and from up-close in space – because assumptions and models are just that,” Enos said.

    Goddard provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator. The university leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate Washington.

    For more information about OSIRIS-REx, visit: http://www.nasa.gov/osiris-rex

     

    Alana Johnson / Karen Fox
    NASA Headquarters, Washington
    202-672-4780 / 202-358-0668
    alana.r.johnson@nasa.gov / karen.c.fox@nasa.gov

    Rani Gran
    Goddard Space Flight Center, Greenbelt, Md.
    301-286-2483
    rani.c.gran@nasa.gov

  5. NASA’s OSIRIS-REx MOMs Help Asteroid Mission Thrive

    May 7, 2021 -

    Kids depend on their parents and guardians for care, support, and guidance—and their importance in the lives of children is often celebrated with designated days, like Mother’s Day on Sunday May 9th; NASA missions are no different and have MOMs of their own. MOM is NASA speak for Mission Operation Managers. A NASA MOM manages all the activities associated with communicating with the spacecraft and keeping it safe and healthy.

    Most space missions have at least one MOM on their team. However, OSIRIS-REx (NASA Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer), NASA’s first asteroid sample return mission, needed three. “It’s not easy to maneuver a spacecraft near an asteroid and to orbit it safely,” said Andrew Calloway, the OSIRIS-REx Mission Operations Manager (MOM) at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The nature and the complexity of this mission calls us to have more people.”

    Devin Poland, NASA OSIRIS-REx MOM notes: My mother is a strong, hard working woman who always saw the best in us. She worked tirelessly to inspire my brother, sister and myself to be kind, generous and to communicate in an effective manner. She has been the glue that binds us for as long as I can remember. As a MOM it is necessary to plan future activities, work to resolve conflicts effectively and be someone the different mission elements can rely on to bring the mission together. Working to lead from within, to inspire the team in the same way my mother worked to inspire me and my siblings, is a critical aspect of being a MOM.
    Credit: Courtesy of D. Poland

    OSIRIS-REx became the first-ever NASA mission to travel to an asteroid and collect a sample for study back on Earth. OSIRIS-REx broke records for the closest-ever orbit of a planetary body by a spacecraft. After two years orbiting asteroid Bennu, OSIRIS-REx collected its sample in October 2020 and is preparing to begin the journey home.

    Andrew Calloway, Nayi Castro, and Devin Poland make up NASA Goddard’s OSIRIS-REx three-MOM team. They work closely with all elements of the project nationwide to make sure the spacecraft remains safe and is thriving as it conducts its science observations of asteroid Bennu.

    Based in Maryland, Arizona, Colorado, and California, OSIRIS-REx team members generate multiple weekly products for the spacecraft to operate and maneuver precisely around Bennu. The widely distributed team was a challenge for the MOMs, and became particularly difficult during COVID 19.

    The three OSIRIS-REx MOMS were essential to cover the “late updates” performed several times per week. The process provides the spacecraft with the most up-to-date navigation and trajectory information, essential for the precision flying and science observations close to the asteroid. It is a quick-turnaround, orchestrated sequence of events performed over 24 hours to compute new command parameters and get them uplinked to the spacecraft.

    “We touch all four teams; navigation, flight dynamics, spacecraft operations and science teams within 24 hours,” Poland said. “Then the flight team uplinked those products to the spacecraft, only hours before the spacecraft does the maneuver.”

    Andrew Calloway, NASA OSIRIS-REx MOM notes: My mom Iris was an amazing woman who inspired and supported me every step of the way on my life’s journey, from long division homework in grade school to my college graduation and beyond. Iris lost her battle with cancer in 2019, but her legacy lives on in me and in my own children as we dare to explore the solar system and learn about the universe around us. As a MOM and a dad, I see humorous similarities between the two. Spacecraft are dependent on us in their first year as we bond. They tend to throw tantrums in their next couple of years, but we love them anyway. We try to nurture them, keep them healthy and safe, teach them right from wrong, and they can be quite temperamental when they reach their teens. The rewards far outweigh the challenges though, and we miss them dearly when they stop calling us. Credit: Courtesy of A. Calloway

    The updates spanned second and third shifts along with many weekends. “Late updates were a big stressor for the entire operations team, because there were so many of them performed over two plus years of proximity operations at Bennu,” said Michael Moreau, OSIRIS-REx deputy project manager at Goddard. “The three MOMs were an essential part of the coordination that was necessary for this process to work.”

    The mission completed ‘107’ late updates and hundreds more navigation late updates during its operations at Bennu.

    The MOMs have developed a close working relationship with each other and the team members around the country. “Each manager brings a different strength and diverse perspective and background to the project,” Calloway said. “This was crucial for solving some of the most complex problems on the mission.”

    Both Calloway and Castro supported mid- and long-term planning for the mission. Poland took care of the day-to-day flight operations focusing on technical requirements.

    Calloway joined NASA Goddard’s OSIRIS-REx team five months prior to launch in April 2016, on loan from the Johns Hopkins Applied Physics Laboratory in neighboring Laurel, Maryland, under an inter-agency agreement. Calloway was a MOM on NASA’s Mercury MESSENGER mission for eight years and a core team member of NASA’s New Horizons mission to Pluto.

    Calloway’s experience was a complementary asset to OSIRIS-REx since Castro and Poland were first-time MOMs on the project. Poland has worked at Goddard for 10 years on various flight projects. He supports OSIRIS-REx’s day-to-day flight operations reviewing the multiple products generated by OSIRIS-REx teams.

    Nayi Castro, NASA OSIRIS-REx MOM notes: My mother was my first role model. She means more to me than words can express. She taught me to be grateful and to strive for kindness in all that I do. She taught me early on how to read and to pursue my aspirations. I admire her greatly and am forever thankful for her unwavering love, support, and friendship. As a MOM, I experienced firsthand a lot of the development of ideas from infancy to execution. This team has further taught me how to work through difficult decisions and bolster resilience. Credit: Courtesy of N. Castro

    Castro joined the team in 2018 as the spacecraft was approaching asteroid Bennu. She has worked on the Lunar Reconnaissance Orbiter, and the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft and also works with the Deep Space Network (DSN), scheduling time to upload and download data and monitor critical events. OSIRIS-REx shares the network with other missions. It was difficult to negotiating with different missions to get OSIRIS-REx enough time on the network for the late updates.

    At times, emergencies with the DSN tested the MOMs’ skills, but it also illustrated why OSIRIS-REx needs three MOMs. A facility of the Deep Space Network near Madrid had a network outage that stopped a late update. The mission team could not complete the first step: downloading data from the spacecraft. DSN time was ticking away, reducing their communication time with the spacecraft.

    The team did not want to lose their opportunity for a critical update and the subsequent observations. If they did, it would delay the next flyover and ultimately delay the asteroid sample collection maneuver. The team found a way to condense the 24-hour ‘late update’ into 4 hours with all hands-on deck. The team named this update the “super late update”.

    The mission team conducted the process successfully, allowing OSIRIS-REx to complete that important flyover of a potential sample site.

    As OSIRIS-REx’s time at Bennu comes to an end so does the need for a three-MOM team. The MOMs have completed the most challenging phases of the mission with the exception of return to Earth in 2023. The final flyby of Bennu occurred on April 7, 2021.

    Following the successful sample collection, Calloway has returned to the Applied Physics Laboratory after five years on the team. Castro was promoted to OSIRIS-REx lead MOM and oversaw the mission’s last flyover of Bennu. Poland continues to provide technical support to OSIRIS-REx and has transitioned to be the MOM for another NASA asteroid mission, named Lucy. NASA plans to launch Lucy in September 2021.

    Happy Mother’s Day to all the moms out there.

    By Rani Gran
    NASA’s Goddard Space Flight Center

    Last Updated: May 7, 2021

    Editor: Lynn Jenner

     

  6. WATCH: OSIRIS-REx will Begin Return to Earth

    May 7, 2021 -

    NASA invites the public and the media to watch its first asteroid sample return mission begin a two-year cruise home at 4 p.m. EDT Monday, May 10, on NASA Televisionthe NASA app, and the agency’s website. The public can follow along on the NASA Solar System InstagramTwitter, and Facebook accounts using #ToBennuAndBack, and ask questions about the mission by commenting on an Instagram story between 12 p.m. EDT, May 10 and 12 p.m. EDT, May 11. Answers will post to NASA Solar System’s Instagram stories on May 11.

    This illustration shows the OSIRIS-REx spacecraft departing asteroid Bennu to begin its two-year journey back to Earth. Credit: NASA/Goddard/University of Arizona

    Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) is the first NASA mission to visit a near-Earth asteroid, survey the surface, and collect a sample to deliver to Earth. During the broadcast, scientists will reveal new imagery from the mission’s final flyover of the asteroid Bennu and discuss the tense moments from the sample grab in October 2020. The broadcast also will cover how the team engineered its way out of challenges that threatened its mission.

    At approximately 4:16 p.m. EDT, the OSIRIS-REx control room located at Lockheed Martin, in Littleton, Colorado, will receive a confirmation that the spacecraft fired its main thrusters to push away from asteroid Bennu’s orbit, approximately 16 minutes after it happened. After 7 minutes of firing its thrusters, OSIRIS-REx will officially start its long journey home with more than 2.1 ounces (60 grams) of asteroid material.

    The OSIRIS-REx departure sequence is the mission’s most significant maneuver since it arrived at Bennu in 2018. The spacecraft’s thrusters must change its velocity by 595 miles per hour (958 kilometers per hour) for OSIRIS-REx’s path to intersect Earth and achieve a successful sample return at the Utah Test and Training Range on Sept. 24, 2023.

    There is no straight path back to Earth. Like a quarterback throwing a long pass to where a receiver will be in the future, OSIRIS-REx is traveling to where the Earth will be. The spacecraft will circle the Sun twice, covering 1.4 billion miles (2.3 billion kilometers) over to catch up with Earth.

    OSIRIS-REx made history many times during its two and half years of operations on the asteroid, including breaking its own record for the closest orbit of a planetary body by a spacecraft. Bennu is the smallest celestial object ever orbited by a human-built spacecraft.

    OSIRIS-REx will bring back the largest sample collected by a NASA mission since the Apollo astronauts returned with Moon rocks. Scientists plan to analyze the sample to learn about the formation of our solar system and the development of Earth as a habitable planet.

    Once recovered, the capsule will be transported to the curation facility at NASA’s Johnson Space Center in Houston, where the sample will be removed for distribution to laboratories worldwide. NASA will set aside 75% of the samples for future generations to study with technologies not yet created.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator. The University of Arizona leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate Washington.

    For more information on OSIRIS-REx, visit: https://www.nasa.gov/osiris-rex

    Karen Fox / Alana Johnson
    Headquarters, Washington
    301-286-6284 / 202-358-1501
    karen.c.fox@nasa.gov / alana.r.johnson@nasa.gov

    Rani Gran
    Goddard Space Flight Center, Greenbelt, Md.
    301-286-2483
    Rani.C.Gran@nasa.gov

  7. OSIRIS-REx ‘MOM’ (That’s ‘Mission Operations Manager’ in NASA-speak) Says Goodbye to an Asteroid

    April 26, 2021 -

    Nayi Castro began working with NASA Goddard’s OSIRIS-REx mission in 2018 as the spacecraft approached Asteroid Bennu. She started on the mission as deputy Mission Operations Manager (MOM). Today she serves in the role of lead MOM. As OSIRIS-REx gets ready to leave Bennu, Castro shares her thoughts on her work with OSIRIS-REx and her career with NASA, as well as her personal interests.

    Nayi Castro, mission operations manager for NASA’s OSIRIS-REx, the agency’s first asteroid sample return mission. Credit: NASA

    What are the responsibilities of a MOM?

    Nayi: I manage all of the activities associated with sending commands to, and receiving data back from, the spacecraft. This includes the communication and transfer of products amongst team members, based in Maryland, Arizona, Colorado, and California, something that became particularly challenging during COVID-19.

    How are you feeling about OSIRIS-REx leaving Bennu?

    Nayi: It’s bittersweet to say goodbye to the asteroid that was our spacecraft’s home since OSIRIS-REx’s arrival in 2018. There was a lot of innovative science and engineering tailored to the design and operation of OSIRIS-REx, by an incredible team. As the team starts to focus on return cruise and Earth reentry operations, I am excited to know that scientists will have a piece of Bennu to study and further deepen our understanding of our cosmic surroundings and of ourselves.

    It will take OSIRIS-REx two years to cruise back to Earth, that’s a long road trip. What music do you like to listen to on long road trips?

    Nayi: One of my long road trip playlists would shuffle around Fleetwood Mac, Converge, Florence + the Machine, Bright Eyes, Brandy, Cursive, Bruce Springsteen, Marc Anthony, Misfits, David Bowie, Ms. Lauryn Hill, Glassjaw, Hermanos Gutierrez, The Roots, Jewel, mewithoutYou, Louie Vega, Grupo Niche, Pixies, Ricardo Arjona, The Smiths, The Mountain Goats, The Clash, and on and on.

    What was your favorite moment during the mission?

    Nayi: With 2020 being such a difficult year for humankind, I was fortunate to be on a team that prioritized health, safety, and continued mission success. A favorite thing for me to observe was the progress made through each 2020 mission milestone, such as the Checkpoint Rehearsal, Matchpoint Rehearsal, and ultimately the Touch-and-Go (TAG) asteroid sample collection. It was inspiring to see a team’s dedication striving towards a shared objective, despite being further socially distanced and geographically separated than before.

    Credit: NASA

    How did you get to NASA? What training or jobs or interests led you to this position?

    Nayi: As a child, I found the work at NASA centers fascinating.  When my parents watched the news, if there happened to be a segment on a NASA mission, my ears would perk up because I thought it was incredible that we could learn about objects beyond our home planet. My uncle’s enthusiasm for space missions and the technology and science supporting them also greatly influenced me.

    I pursued my curiosity of space via an Astronautical engineering degree. While I was still in school, NASA and my undergraduate program initiated my career in spacecraft operations when they granted me the opportunity to certify as a flight controller on a NASA mission

    What is your favorite, most challenging, or most rewarding part of the work?

    Nayi: My favorite part of this work is seeing the achievements that are a direct result of every team member’s hard work. It is inspiring to work among science and engineering experts who continuously explore and understand Earth and outer space. I am delighted that these discoveries can then be shared with everyone. It is rewarding to take a step back and appreciate the depth of knowledge that has been collected for decades.

    What missions have you worked on for NASA before OSIRIS-REx?

    Nayi: I’ve been fortunate to work on two NASA Earth-observing missions and a lunar mission. I was a college intern when I worked on the Tropical Rainfall Measurement Mission (TRMM).  At TRMM, I learned how to effectively communicate with the satellite and be mindful of good spacecraft health and safety strategies. After TRMM, the Terra mission was my first full-time opportunity. I was part of the flight team that supported 24/7 on-console operations. The next mission was the Lunar Reconnaissance Orbiter (LRO), where I spent most of my operations time. That was a great experience that provided me with various ways to expand my flight console expertise and systems engineering knowledge. I also work with the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. This mission continues to provide an abundance of information on the Martian atmosphere.

    What do you do in your free time – any hobbies or sports or outside interests?

    Nayi: I enjoy reading, practicing yoga, listening to music, and spending time with loved ones. My dogs also bring me a lot of joy!

    Anything else that you’d like people to know?

    Nayi: I hope that people can find a theme of unity and progress in many of the missions that NASA has flown throughout the years. I aspire to support science and engineering to further understand our solar system and beyond and more of ourselves.

     

    By Rani Gran
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

  8. NASA’s OSIRIS-REx Leaves its Mark on Asteroid Bennu

    April 20, 2021 -

    Like boot prints on the Moon, NASA’s OSIRIS-REx spacecraft left its mark on asteroid Bennu. Now, new images — taken during the spacecraft’s final fly-over on April 7 — reveal the aftermath of its historic encounter with the asteroid.

    Bennu’s surface was disturbed in three different ways: by the force of the spacecraft touching down; by the sampling mechanism, which collected material by blowing gas into its collection filter; and by four of the spacecraft’s back-away thrusters, which moved the spacecraft away from the sample site and agitated dust and boulders on the surface. The image above shows the TAG site and highlights a large boulder thrown about 40 feet (about 12 meters). Credit: NASA/Goddard/University of Arizona

    The spacecraft flew within 2.3 miles (3.7 km) of the asteroid — the closest it has been since the Touch-and-Go, or TAG, sample collection event on Oct. 20, 2020. During TAG, the spacecraft’s sampling head sunk 1.6 feet (48.8 centimeters) into the asteroid’s surface and simultaneously fired a pressurized charge of nitrogen gas, churning up surface material and driving some into the collection chamber. The spacecraft’s thrusters also launched rocks and dust during the maneuver to reverse course and safely back away from the asteroid.

    Comparing the two images reveals obvious signs of surface disturbance. At the sample collection point, there appears to be a depression, with several large boulders evident at the bottom, suggesting that they were exposed by sampling. There is a noticeable increase in the amount of highly reflective material near the TAG point against the generally dark background of the surface, and many rocks were moved around.

    View of the Nightingale sample site before the TAG event. Images were taken on March 7, 2019, by the spacecraft’s PolyCam instrument, as part of the mission’s global mapping campaign. Credit: NASA/Goddard/University of Arizona

    Where thrusters fired against the surface, substantial mass movement is apparent. Multiple sub-meter boulders were mobilized by the plumes into a campfire ring–like shape — similar to rings of boulders seen around small craters pocking the surface.

    Jason Dworkin, the mission’s project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, noticed that one boulder measuring 4 feet (1.25 meters) across on the edge of the sampling site seemed to appear only in the post-TAG image. “The rock probably weighs around a ton, with a mass somewhere between a cow and a car.”

    Dante Lauretta, of the University of Arizona and the mission’s principal investigator, later pointed out that this boulder is likely one of those present in the pre-TAG image, but much nearer the sampling location, and estimates it was thrown a distance of 40 feet (about 12 meters) by the sample collection event.

    In order to compare the before and after images, the team had to meticulously plan this final flyover. “Bennu is rough and rocky, so if you look at it from a different angle or capture it at a time when the sun is not directly overhead, that dramatically changes what the surface looks like,” says Dathon Golish, a member of the OSIRIS-REx image processing working group, headquartered at the University of Arizona. “These images were deliberately taken close to noon, with the Sun shining straight down, when there’s not as many shadows.”

    View of the Nightingale sample site after the TAG event. Images were taken on April 7, 2021, as part of a final observation campaign to document the state of the surface after TAG. Credit: NASA/Goddard/University of Arizona

    “These observations were not in the original mission plan, so we were excited to go back and document what we did,” Golish said. “The team really pulled together for this one last hurrah.”

    The spacecraft will remain in Bennu’s vicinity until departure on May 10, when the mission will begin its two-year return cruise back to Earth. As it approaches Earth, the spacecraft will jettison the Sample Return Capsule (SRC) that contains the sample from Bennu. The SRC will then travel through Earth’s atmosphere and land under parachutes at the Utah Test and Training Range on Sept. 24, 2023.

    Once recovered, the capsule will be transported to the curation facility at NASA’s Johnson Space Center in Houston, where the sample will be removed for distribution to laboratories worldwide, enabling scientists to study the formation of our solar system and Earth as a habitable planet. NASA will set 75% of the sample aside for future generations to study with technologies not invented yet.

    The OSIRIS-REx mission is the first NASA mission to visit a near-Earth asteroid, survey the surface, and collect a sample to deliver to Earth.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington, D.C.

    For more information about OSIRIS-REx visit: https://www.nasa.gov/osiris-rex

     

    By Mikayla Mace Kelley
    University of Arizona, Tucson, Ariz.

    and by Rani Gran
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

  9. NASA’s OSIRIS-REx Completes Final Tour of Asteroid Bennu

    April 7, 2021 -

    NASA’s OSIRIS-REx completed its last flyover of Bennu in around 6 am (EDT), 4am (MDT) April 7th and is now slowly drifting away from the asteroid; however, the mission team will have to wait a few more days to find out how the spacecraft changed the surface of Bennu when it grabbed a sample of the asteroid.

    This image shows a top-down view of asteroid Bennu, with a portion of the asteroid’s equatorial ridge and northern hemisphere illuminated. It was taken by the PolyCam camera on NASA’s OSIRIS-REx spacecraft on March 4, from a distance of about 186 miles (300 km). Credit: NASA/Goddard/University of Arizona

    The OSIRIS-REx team added this flyby to document surface changes resulting from the Touch and Go (TAG) sample collection maneuver October 20, 2020. “By surveying the distribution of the excavated material around the TAG site, we will learn more about the nature of the surface and subsurface materials along with the mechanical properties of the asteroid,” said Dr. Dante Lauretta, Principal Investigator for OSIRIS-REx at the University of Arizona.

    During the flyby, OSIRIS-REx imaged Bennu for 5.9 hours, covering more than a full rotation of the asteroid. It flew within 2.1 miles (3.5 kilometers) distance to the surface of Bennu – the closest it’s been since the TAG sample collection event.

    It will take until at least April 13th for OSIRIS-REx to downlink all of the data and new pictures of Bennu’s surface recorded during the flyby. It shares the Deep Space Network Antennae with other missions like Mars Perseverance, and typically gets 4-6 hours of downlink time per day. “We collected about 4,000 megabytes of data during the flyby,” said Mike Moreau, Deputy Project Manager of OSIRIS-REx at NASA Goddard Spaceflight Center. “Bennu is approximately 185 million miles from Earth right now, which means we can only achieve a downlink data-rate of 412 kilobits per second, so it will take several days to download all of the flyby data.”

    Once the mission team receives the images and other instrument data, they will study how OSIRIS-REx jumbled up Bennu’s surface. During touchdown, the spacecraft’s sampling head sunk 1.6 feet (48.8 centimeters) into the asteroid’s surface and simultaneously fired a pressurized charge of nitrogen gas. The spacecraft’s thrusters kicked up a large amount of surface material during the back-away burn – launching rocks and dust in the process.

    KinetX Flight Navigator, Leilah McCarthy, processes navigation images to help target NASA’s OSIRIS-REx final flyby of Bennu. Credit: KinetX Inc./Coralie Adam

    OSIRIS-REx, with its pristine and precious asteroid cargo, will remain in the vicinity of Bennu until May 10 when it will fire its thrusters and begin its two-year cruise home. The mission will deliver the asteroid sample to Earth September 24, 2023.

    NASA invites the public to watch OSIRIS-REx depart from Bennu on NASA.gov and NASA TV, at 4 PM EDT.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security – Regolith Explorer). Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

    Written by Rani Gran.

    For more information about this story and OSIRIS-REx visit: https://www.nasa.gov/osiris-rex

  10. OSIRIS-REx’s Final Asteroid Observation Run

    April 1, 2021 -

    NASA’s OSIRIS-REx mission is on the brink of discovering the extent of the mess it made on asteroid Bennu’s surface during last fall’s sample collection event. On Apr. 7, the OSIRIS-REx spacecraft will get one last close encounter with Bennu as it performs a final flyover to capture images of the asteroid’s surface. While performing the flyover, the spacecraft will observe Bennu from a distance of about 2.3 miles (3.7 km) – the closest it’s been since the Touch-and-Go Sample Collection event on Oct. 20, 2020.

    This artist’s concept shows the planned flight path of NASA’s OSIRIS-REx spacecraft during its final flyby of asteroid Bennu, which is scheduled for April 7. Credit: NASA/Goddard/University of Arizona

    The OSIRIS-REx team decided to add this last flyover after Bennu’s surface was significantly disturbed by the sample collection event. During touchdown, the spacecraft’s sampling head sunk 1.6 feet (48.8 centimeters) into the asteroid’s surface and simultaneously fired a pressurized charge of nitrogen gas. The spacecraft’s thrusters also mobilized a substantial amount of surface material during the back-away burn. Because Bennu’s gravity is so weak, these various forces from the spacecraft had a dramatic effect on the sample site – launching many of the region’s rocks and a lot of dust in the process. This final flyby of Bennu will provide the mission team an opportunity to learn how the spacecraft’s contact with Bennu’s surface altered the sample site and the region surrounding it.

    The single flyby will mimic one of the observation sequences conducted during the mission’s Detailed Survey phase in 2019. OSIRIS-REx will image Bennu for 5.9 hours, which is just over a full rotation period of the asteroid. Within this timeframe, the spacecraft’s PolyCam imager will obtain high-resolution images of Bennu’s northern and southern hemispheres and its equatorial region. The team will then compare these new images with the previous high-resolution imagery of the asteroid obtained during 2019.

    Most of the spacecraft’s other science instruments will also collect data during the flyover, including the MapCam imager, the OSIRIS-REx Thermal Emission Spectrometer (OTES), the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS), and the OSIRIS-REx Laser Altimeter (OLA). Exercising these instruments will give the team a chance to assess the current state of each science instrument onboard the spacecraft, as dust coated the instruments during the sample collection event. Understanding the health of the instruments is also part of NASA’s evaluation of possible extended mission opportunities after the sample is delivered to Earth.

    After the Bennu flyby, it will take several days for the data from the flyover to be downlinked to Earth. Once the data are downlinked, the team will inspect the images to understand how OSIRIS-REx disturbed the asteroid’s surface material. At this point, the team will also be able to evaluate the performance of the science instruments.

    The spacecraft will remain in asteroid Bennu’s vicinity until May 10, when the mission will enter its Return Cruise phase and begin its two-year journey back to Earth. As it approaches Earth, the spacecraft will jettison the Sample Return Capsule (SRC) that contains the rocks and dust collected from Bennu. The SRC will then travel through the Earth’s atmosphere and land under parachutes at the Utah Test and Training Range on Sep. 24, 2023.

    Once recovered, the capsule will be transported to the curation facility at the agency’s Johnson Space Center in Houston, where the sample will be removed for distribution to laboratories worldwide, enabling scientists to study the formation of our solar system and Earth as a habitable planet.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  11. OSIRIS-REx to Fly a Farewell Tour of Bennu

    February 8, 2021 -

    On April 7, NASA’s OSIRIS-REx mission will give asteroid Bennu one last glance before saying farewell. Before departing for Earth on May 10, the OSIRIS-REx spacecraft will perform a final flyby of Bennu – capturing its last images of sample collection site Nightingale to look for transformations on Bennu’s surface after the Oct. 20, 2020, sample collection event.

    This artist’s concept shows the planned flight path of NASA’s OSIRIS-REx spacecraft during its final flyby of asteroid Bennu, which is scheduled for April 7. Credit: NASA/Goddard/University of Arizona

    The OSIRIS-REx mission team recently completed a detailed safety analysis of a trajectory to observe sample site Nightingale from a distance of approximately 2.4 miles (3.8 kilometers). The spacecraft’s flight path is designed to keep OSIRIS-REx a safe distance from Bennu, while ensuring the science instruments can collect precise observations. The single flyby will mimic one of the observation sequences conducted during the mission’s Detailed Survey phase in 2019. OSIRIS-REx will image Bennu for a full 4.3-hour rotation to obtain high-resolution images of the asteroid’s northern and southern hemispheres and its equatorial region. The team will then compare these new images with the previous high-resolution imagery of Bennu obtained during 2019.

    This final flyby of Bennu was not part of the original mission schedule, but the observation run will provide the team an opportunity to learn how the spacecraft’s contact with Bennu’s surface altered the sample site. Bennu’s surface was considerably disturbed after the Touch-and-Go (TAG) sample collection event, with the collector head sinking 1.6 feet (48.8 centimeters) into the asteroid’s surface while firing a pressurized charge of nitrogen gas. The spacecraft’s thrusters also mobilized a substantial amount of surface material during the back-away burn.

    During this new mission phase, called the Post-TAG Observation (PTO) phase, the spacecraft will perform five separate navigation maneuvers in order to return to the asteroid and position itself for the flyby. OSIRIS-REx executed the first maneuver on Jan. 14, which acted as a braking burn and put the spacecraft on a trajectory to rendezvous with the asteroid one last time. Since October’s sample collection event, the spacecraft has been slowly drifting away from the asteroid, and ended up approximately 1,635 miles (2,200 km) from Bennu. After the braking burn, the spacecraft is now slowly approaching the asteroid and will perform a second approach maneuver on Mar. 6, when it is approximately 155 miles (250 km) from Bennu. OSIRIS-REx will then execute three subsequent maneuvers, which are required to place the spacecraft on a precise trajectory for the final flyby on Apr. 7.

    This artist’s concept shows the OSIRIS-REx spacecraft departing asteroid Bennu to begin its two-year journey back to Earth. Credit: NASA/Goddard/University of Arizona

    OSIRIS-REx is scheduled to depart Bennu on May 10 and begin its two-year journey back to Earth. The spacecraft will deliver the samples of Bennu to the Utah Test and Training Range on Sep. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  12. NASA’s OSIRIS-REx Mission Plans for May Asteroid Departure

    January 26, 2021 -

    On May 10, NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft will say farewell to asteroid Bennu and begin its journey back to Earth. During its Oct. 20, 2020, sample collection event, the spacecraft collected a substantial amount of material from Bennu’s surface, likely exceeding the mission’s requirement of 2 ounces (60 grams). The spacecraft is scheduled to deliver the sample to Earth on Sep. 24, 2023.

    This artist’s concept shows the OSIRIS-REx spacecraft departing asteroid Bennu to begin its two-year journey back to Earth. Credit: NASA/Goddard/University of Arizona

    “Leaving Bennu’s vicinity in May puts us in the ‘sweet spot,’ when the departure maneuver will consume the least amount of the spacecraft’s onboard fuel,” said Michael Moreau, OSIRIS-REx deputy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Nevertheless, with over 593 miles per hour (265 meters per second) of velocity change, this will be the largest propulsive maneuver conducted by OSIRIS-REx since the approach to Bennu in October 2018.”

    The May departure also provides the OSIRIS-REx team with the opportunity to plan a final spacecraft flyby of Bennu. This activity was not part of the original mission schedule, but the team is studying the feasibility of a final observation run of the asteroid to potentially learn how the spacecraft’s contact with Bennu’s surface altered the sample site.

    If feasible, the flyby will take place in early April and will observe the sample site, named Nightingale, from a distance of approximately 2 miles (3.2 kilometers). Bennu’s surface was considerably disturbed after the Touch-and-Go (TAG) sample collection event, with the collector head sinking 1.6 feet (48.8 centimeters) into the asteroid’s surface. The spacecraft’s thrusters also disturbed a substantial amount of surface material during the back-away burn.

    The mission is planning a single flyby, mimicking one of the observation sequences conducted during the mission’s Detailed Survey phase in 2019. OSIRIS-REx would image Bennu for a full rotation to obtain high-resolution images of the asteroid’s northern and southern hemispheres and equatorial region. The team would then compare these new images with the previous high-resolution imagery of Bennu obtained during 2019.

    “OSIRIS-REx has already provided incredible science,” said Lori Glaze, NASA’s director of planetary science at the agency’s headquarters in Washington. “We’re really excited the mission is planning one more observation flyby of asteroid Bennu to provide new information about how the asteroid responded to TAG and to render a proper farewell.”

    These post-TAG observations would also give the team a chance to assess the current functionality of science instruments onboard the spacecraft – specifically the OSIRIS-REx Camera Suite (OCAMS), OSIRIS-REx Thermal Emission Spectrometer (OTES), OSIRIS-REx Visible and Infrared Spectrometer (OVIRS), and OSIRIS-REx Laser Altimeter (OLA). It is possible dust coated the instruments during the sample collection event and the mission wants to evaluate the status of each. Understanding the health of the instruments is also part of the team’s assessment of possible extended mission opportunities after the sample is delivered to Earth.

    The spacecraft will remain in asteroid Bennu’s vicinity until May 10, when the mission will enter its Earth Return Cruise phase. As it approaches Earth, OSIRIS-REx will jettison the Sample Return Capsule (SRC). The SRC will then travel through the Earth’s atmosphere and land under parachutes at the Utah Test and Training Range.

    Once recovered, NASA will transport the capsule to the curation facility at the agency’s Johnson Space Center in Houston and distribute the sample to laboratories worldwide, enabling scientists to study the formation of our solar system and Earth as a habitable planet.

    Goddard provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona in  Tucson is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages for the agency’s Science Mission Directorate in Washington.

  13. NASA’s OSIRIS-REx Successfully Stows Sample of Asteroid Bennu

    October 29, 2020 -

    NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) mission has successfully stowed the spacecraft’s Sample Return Capsule (SRC) and its abundant sample of asteroid Bennu. On Wednesday, Oct. 28, the mission team sent commands to the spacecraft, instructing it to close the capsule – marking the end of one of the most challenging phases of the mission.

    Captured on Oct. 28, this imaging sequence shows NASA’s OSIRIS-REx spacecraft completing the final step of the sample stowage process: closing its SRC. To seal the SRC, the spacecraft closes the lid and then secures two internal latches. The sample of Bennu is now safely stored and ready for its journey to Earth. The image sequence was captured by the StowCam camera. StowCam, a color imager, is one of three cameras comprising TAGCAMS (the Touch-and-Go Camera System), which is part of OSIRIS-REx’s guidance, navigation, and control system. TAGCAMS was designed, built and tested by Malin Space Science Systems; Lockheed Martin integrated TAGCAMS to the OSIRIS-REx spacecraft and operates TAGCAMS. Credit: NASA/Goddard/University of Arizona/Lockheed Martin

    “This achievement by OSIRIS-REx on behalf of NASA and the world has lifted our vision to the higher things we can achieve together, as teams and nations,” said NASA Administrator Jim Bridenstine. “Together a team comprising industry, academia and international partners, and a talented and diverse team of NASA employees with all types of expertise, has put us on course to vastly increase our collection on Earth of samples from space. Samples like this are going to transform what we know about our universe and ourselves, which is at the base of all NASA’s endeavors.”

    The mission team spent two days working around the clock to carry out the stowage procedure, with preparations for the stowage event beginning last weekend. The process to stow the sample is unique compared to other spacecraft operations and required the team’s continuous oversight and input over the two-day period. For the spacecraft to proceed with each step in the stowage sequence, the team had to assess images and telemetry from the previous step to confirm the operation was successful and the spacecraft was ready to continue. Given that OSIRIS-REx is currently more than 205 million miles (330 million km) from Earth, this required the team to also work with a greater than 18.5-minute time delay for signals traveling in each direction.

    Throughout the process, the OSIRIS-REx team continually assessed the Touch-And-Go Sample Acquisition Mechanism’s (TAGSAM) wrist alignment to ensure the collector head was being placed properly into the SRC. Additionally, the team inspected images to observe any material escaping from the collector head to confirm that no particles would hinder the stowage process. StowCam images of the stowage sequence show that a few particles escaped during the stowage procedure, but the team is confident that a plentiful amount of material remains inside of the head.

    “Given the complexity of the process to place the sample collector head onto the capture ring, we expected that it would take a few attempts to get it in the perfect position,” said Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Fortunately, the head was captured on the first try, which allowed us to expeditiously execute the stow procedure.”

    By the evening of Oct. 27, the spacecraft’s TAGSAM arm had placed the collector head into the SRC. The following morning, the OSIRIS-REx team verified that the collector head was thoroughly fastened into the capsule by performing a “backout check.” This sequence commanded the TAGSAM arm to attempt to back out of the capsule – which tugged on the collector head and ensured the latches are well secured.

    “I want to thank the OSIRIS-REx team from the University of Arizona, NASA Goddard, Lockheed Martin, and their partners, and also especially the SCaN and Deep Space Network people at NASA and JPL, who worked tirelessly to get us the bandwidth we needed to achieve this milestone, early and while still hundreds of millions of miles away,” said Thomas Zurbuchen, NASA’s associate administrator for science at the agency’s headquarters in Washington. “What we have done is a real first for NASA, and we will benefit for decades by what we have been able to achieve at Bennu.”

    On the afternoon of Oct. 28, following the backout check, the mission team sent commands to disconnect the two mechanical parts on the TAGSAM arm that connect the sampler head to the arm. The spacecraft first cut the tube that carried the nitrogen gas that stirred up the sample through the TAGSAM head during sample collection, and then separated the collector head from the TAGSAM arm itself.

    That evening, the spacecraft completed the final step of the sample stowage process  –closing the SRC. To secure the capsule, the spacecraft closed the lid and then fastened two internal latches. As of late Oct. 28, the sample of Bennu is safely stored and ready for its journey to Earth.

    “I’m very thankful that our team worked so hard to get this sample stowed as quickly as they did,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “Now we can look forward to receiving the sample here on Earth and opening up that capsule.”

    The stowage process, originally scheduled to begin in early November, was expedited after sample collection when the mission team received images that showed the spacecraft’s collector head overflowing with material. The images indicated that the spacecraft collected well over 2 ounces (60 grams) of Bennu’s surface material, and that some of these particles appeared to be slowly escaping from the head. A mylar flap designed to keep the sample inside the head appeared to be wedged open by some larger rocks. Now that the head is secure inside the SRC, pieces of the sample will no longer be lost.

    The OSIRIS-REx team will now focus on preparing the spacecraft for the next phase of the mission – Earth Return Cruise. The departure window opens in March 2021 for OSIRIS-REx to begin its voyage home, and the spacecraft is targeting delivery of the SRC to Earth on Sep. 24, 2023.

    Goddard provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Littleton built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  14. OSIRIS-REx in the Midst of Stow

    October 28, 2020 -

    Yesterday, NASA’s OSIRIS-REx mission successfully placed the spacecraft’s sample collector head into its Sample Return Capsule (SRC). The first image shows the collector head hovering over the SRC after the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) arm moved it into the proper position for capture. The second image shows the collector head secured onto the capture ring in the SRC. Both images were captured by the StowCam camera.

    Yesterday, NASA’s OSIRIS-REx mission successfully placed the spacecraft’s sample collector head into its Sample Return Capsule (SRC). The first image shows the collector head hovering over the SRC after the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) arm moved it into the proper position for capture. The second image shows the collector head secured onto the capture ring in the SRC.
    Credit: NASA/Goddard/University of Arizona/Lockheed Martin

    Today, after the head was seated into the SRC’s capture ring, the spacecraft performed a “backout check,” which commanded the TAGSAM arm to back out of the capsule. This maneuver is designed to tug on the collector head and ensure that the latches – which keep the collector head in place – are well secured. Following the test, the mission team received telemetry confirming that the head is properly secured in the SRC.

    Before the sampler head can be sealed into the SRC, two mechanical parts on the TAGSAM arm must first be disconnected – these are the tube that carried the nitrogen gas to the TAGSAM head during sample collection and the TAGSAM arm itself. Over the next several hours, the mission team will command the spacecraft to cut the tube and separate the collector head from the TAGSAM arm. Once the team confirms these activities have executed as planned, they will command the spacecraft to seal the SRC.

    StowCam, a color imager, is one of three cameras comprising TAGCAMS (the Touch-and-Go Camera System), which is part of OSIRIS-REx’s guidance, navigation, and control system. TAGCAMS was designed, built and tested by Malin Space Science Systems; Lockheed Martin integrated TAGCAMS to the OSIRIS-REx spacecraft and operates TAGCAMS.

  15. NASA’s OSIRIS-REx Spacecraft Goes for Early Stow of Asteroid Sample

    October 26, 2020 -

    NASA’s OSIRIS-REx mission is ready to perform an early stow on Tuesday, Oct. 27, of the large sample it collected last week from the surface of the asteroid Bennu to protect and return as much of the sample as possible.

    Artist’s conception of NASA’s OSIRIS-REx spacecraft stowing the sample it collected from asteroid Bennu. The spacecraft will use its Touch-And-Go Sample Acquisition Mechanism (TAGSAM) arm to place the TAGSAM collector head into the Sample Return Capsule (SRC).
    Credit: NASA/Goddard/University of Arizona

    On Oct. 22, the OSIRIS-REx mission team received images that showed the spacecraft’s collector head overflowing with material collected from Bennu’s surface – well over the two-ounce (60-gram) mission requirement – and that some of these particles appeared to be slowly escaping from the collection head, called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM).

    A mylar flap on the TAGSAM allows material to easily enter the collector head, and should seal shut once the particles pass through. However, larger rocks that didn’t fully pass through the flap into the TAGSAM appear to have wedged this flap open, allowing bits of the sample to leak out.

    Because the first sample collection event was so successful, NASA’s Science Mission Directorate has given the mission team the go-ahead to expedite sample stowage, originally scheduled for Nov. 2, in the spacecraft’s Sample Return Capsule (SRC) to minimize further sample loss.

    “The abundance of material we collected from Bennu made it possible to expedite our decision to stow,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “The team is now working around the clock to accelerate the stowage timeline, so that we can protect as much of this material as possible for return to Earth.”

    Unlike other spacecraft operations where OSIRIS-REx autonomously runs through an entire sequence, stowing the sample is done in stages and requires the team’s oversight and input. The team will send the preliminary commands to the spacecraft to start the stow sequence and, once OSIRIS-REx completes each step in sequence, the spacecraft sends telemetry and images back to the team on Earth and waits for the team’s confirmation to proceed with the next step.

    Signals currently take just over 18.5 minutes to travel between Earth and the spacecraft one-way, so each step of the sequence factors in about 37 minutes of communications transit time. Throughout the process, the mission team will continually assess the TAGSAM’s wrist alignment to ensure the collector head is properly placed in the SRC. A new imaging sequence also has been added to the process to observe the material escaping from the collector head and verify that no particles hinder the stowage process. The mission anticipates the entire stowage process will take multiple days, at the end of which the sample will be safely sealed in the SRC for the spacecraft’s journey back to Earth.

    “I’m proud of the OSIRIS-REx team’s amazing work and success to this point,” said NASA’s Associate Administrator for Science Thomas Zurbuchen. “This mission is well positioned to return a historic and substantial sample of an asteroid to Earth, and they’ve been doing all the right things, on an expedited timetable, to protect that precious cargo.”

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  16. NASA’s OSIRIS-REx Spacecraft Collects Significant Amount of Asteroid Bennu

    October 23, 2020 -

    Two days after touching down on asteroid Bennu, NASA’s OSIRIS-REx mission team received on Thursday, Oct. 22, images that confirm the spacecraft has collected more than enough material to meet one of its main mission requirements – acquiring at least 2 ounces (60 grams) of the asteroid’s surface material.

    Captured on Oct. 22, this series of three images shows that the Touch-and-Go Sample Acquisition Mechanism (TAGSAM) head on NASA’s OSIRIS-REx spacecraft is full of rocks and dust collected from asteroid Bennu. The image series also shows that some of these particles are slowly escaping the sampler head. Analysis by the OSIRIS-REx team suggests that bits of material are passing through small gaps where the head’s mylar flap is slightly wedged open. The mylar flap (the black bulge visible in the 9 o’clock position inside the ring) is designed to keep the collected material locked inside, and these unsealed areas appear to be caused by larger rocks that didn’t fully pass through the flap. Based on available imagery, the team suspects there is plentiful sample inside the head, and is on a path to stow the sample as quickly as possible.
    The images were taken by the spacecraft’s SamCam camera as part of the sample verification procedure following the spacecraft’s Oct. 20 sample collection attempt.The TAGSAM system was developed by Lockheed Martin Space to acquire a sample of asteroid material in a low-gravity environment.
    Credit: NASA/Goddard/University of Arizona

     

    The spacecraft captured images of the sample collector head as it moved through several different positions. In reviewing these images, the OSIRIS-REx team noticed both that the head appeared to be full of asteroid particles, and that some of these particles appeared to be escaping slowly from the sample collector, called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) head. They suspect bits of material are passing through small gaps where a mylar flap – the collector’s “lid” – is slightly wedged open by larger rocks.

    The team believes it has collected a sufficient sample and is on a path to stow the sample as quickly as possible. They came to this conclusion after comparing images of the empty collector head with Oct. 22 images of the TAGSAM head after the sample collection event.

    “Bennu continues to surprise us with great science and also throwing a few curveballs,” said Thomas Zurbuchen, NASA’s associate administrator for science at the agency’s headquarters in Washington. “And although we may have to move more quickly to stow the sample, it’s not a bad problem to have. We are so excited to see what appears to be an abundant sample that will inspire science for decades beyond this historic moment.”

    The images also show that any movement to the spacecraft and the TAGSAM instrument may lead to further sample loss. To preserve the remaining material, the mission team decided to forego the Sample Mass Measurement activity originally scheduled for Saturday, Oct. 24, and canceled a braking burn scheduled for Friday to minimize any acceleration to the spacecraft.

    From here, the OSIRIS-Rex team will focus on stowing the sample in the Sample Return Capsule (SRC), where any loose material will be kept safe during the spacecraft’s journey back to Earth.

    “We are working to keep up with our own success here, and my job is to safely return as large a sample of Bennu as possible,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. “The loss of mass is of concern to me, so I’m strongly encouraging the team to stow this precious sample as quickly as possible.”

    The TAGSAM head performed the sampling event in optimal conditions. Newly available analyses show that the collector head was flush with Bennu’s surface when it made contact and when the nitrogen gas bottle was fired to stir surface material. It also penetrated several centimeters into the asteroid’s surface material. All data so far suggest that the collector head is holding much more than 2 ounces of regolith.

    OSIRIS-REx remains in good health, and the mission team is finalizing a timeline for sample storage. An update will be provided once a decision is made on the sample storage timing and procedures.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  17. OSIRIS-REx TAGS Asteroid Bennu

    October 21, 2020 -

    Captured on Oct. 20, 2020 during the OSIRIS-REx mission’s Touch-And-Go (TAG) sample collection event, this series of images shows the SamCam imager’s field of view as the NASA spacecraft approaches and touches down on asteroid Bennu’s surface, over 200 million miles (321 million km) away from Earth. The sampling event brought the spacecraft all the way down to sample site Nightingale, touching down within three feet (one meter) of the targeted location. The team on Earth received confirmation at 6:08 pm EDT that successful touchdown occurred. Preliminary data show the one-foot-wide (0.3-meter-wide) sampling head touched Bennu’s surface for approximately 6 seconds, after which the spacecraft performed a back-away burn.

    Captured on Oct. 20, during the OSIRIS-REx mission’s Touch-And-Go (TAG) sample collection event, this series of 82 images shows the SamCam imager’s field of view as the NASA spacecraft approaches and touches down on asteroid Bennu’s surface. The sampling event brought the spacecraft all the way down to sample site Nightingale, and the team on Earth received confirmation of successful touchdown at 6:08 pm EDT. Preliminary data show the sampling head touched Bennu’s surface for approximately 6 seconds, after which the spacecraft performed a back-away burn. Credit: NASA/Goddard/University of Arizona

     

    The spacecraft’s sampling arm – called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – is visible in the lower part of the frame. The round head at the end of TAGSAM is the only part of OSIRIS-REx that contacted the surface during the sample collection event. In the middle of the image sequence, the sampling head positions itself to contact the asteroid’s surface head-on. Shortly after, the sampling head impacts site Nightingale and penetrates Bennu’s regolith. Upon initial contact, the TAGSAM head appears to crush some of the porous rocks underneath it. One second later, the spacecraft fires a nitrogen gas bottle, which mobilizes a substantial amount of the sample site’s material. Preliminary data show the spacecraft spent approximately 5 of the 6 seconds of contact collecting surface material, and the majority of sample collection occurred within the first 3 seconds.

    Captured on Oct. 20 during the OSIRIS-REx mission’s Touch-And-Go (TAG) sample collection event, this series of 2 images shows the SamCam imager’s field of view at the moment before and after the NASA spacecraft touched down on asteroid Bennu’s surface. The sampling event brought the spacecraft all the way down to sample site Nightingale, and the team on Earth received confirmation of successful touchdown at 6:08 pm EDT. Preliminary data show the sampling head touched Bennu’s surface for approximately 6 seconds, after which the spacecraft performed a back-away burn. Credit: NASA/Goddard/University of Arizona

     

    The TAGSAM is designed to catch the agitated surface material, and the mission team will assess the amount of material collected through various spacecraft activities. After touchdown, the spacecraft fired its thrusters to back away from Bennu. As expected, this maneuver also disturbed the Nightingale site, and loose debris is visible near the end of the image sequence. Preliminary telemetry shows the spacecraft remains in good health. The spacecraft was traveling at 0.2 mph (10 cm/sec) when it contacted sample site Nightingale and then backed away at 0.9 mph (40 cm/sec).

    Captured on Oct. 20 during the OSIRIS-REx mission’s Touch-And-Go (TAG) sample collection event, this series of 16 images shows the SamCam imager’s field of view as the NASA spacecraft backs away from asteroid Bennu’s surface after touching down. The sampling event brought the spacecraft all the way down to sample site Nightingale, and the team on Earth received confirmation of successful touchdown at 6:08 pm EDT. Preliminary data show the sampling head touched Bennu’s surface for approximately 6 seconds, after which the spacecraft performed a back-away burn. Credit: NASA/Goddard/University of Arizona

     

    These images were captured over approximately a five-minute period. The imaging sequence begins at about 82 feet (25 meters) above the surface, and runs through the back-away maneuver, with the last image in the sequence taken at approximately 43 feet (13 meters) in altitude – about 35 seconds after backing away. The sequence was created using 82 SamCam images, with 1.25 seconds between frames. For context, the images are oriented with Bennu’s west at the top.

  18. NASA’s OSIRIS-REx Spacecraft Successfully Touches Asteroid

    October 20, 2020 -

    NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft unfurled its robotic arm Tuesday, and in a first for the agency, briefly touched an asteroid to collect dust and pebbles from the surface for delivery to Earth in 2023.

    Artist’s conception of NASA’s OSIRIS-REx spacecraft collecting a sample from the asteroid Bennu. Credit: NASA/Goddard/University of Arizona

    This well-preserved, ancient asteroid, known as Bennu, is currently more than 200 million miles (321 million kilometers) from Earth. Bennu offers scientists a window into the early solar system as it was first taking shape billions of years ago and flinging ingredients that could have helped seed life on Earth. If Tuesday’s sample collection event, known as “Touch-And-Go” (TAG), provided enough of a sample, mission teams will command the spacecraft to begin stowing the precious primordial cargo to begin its journey back to Earth in March 2021. Otherwise, they will prepare for another attempt in January.

    “This amazing first for NASA demonstrates how an incredible team from across the country came together and persevered through incredible challenges to expand the boundaries of knowledge,” said NASA Administrator Jim Bridenstine. “Our industry, academic, and international partners have made it possible to hold a piece of the most ancient solar system in our hands.”

    At 1:50 p.m. EDT, OSIRIS-REx fired its thrusters to nudge itself out of orbit around Bennu. It extended the shoulder, then elbow, then wrist of its 11-foot (3.35-meter) sampling arm, known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), and transited across Bennu while descending about a half-mile (805 meters) toward the surface. After a four-hour descent, at an altitude of approximately 410 feet (125 meters), the spacecraft executed the “Checkpoint” burn, the first of two maneuvers to allow it to precisely target the sample collection site, known as “Nightingale.”

    Ten minutes later, the spacecraft fired its thrusters for the second “Matchpoint” burn to slow its descent and match the asteroid’s rotation at the time of contact. It then continued a treacherous, 11-minute coast past a boulder the size of a two-story building, nicknamed “Mount Doom,” to touch down in a clear spot in a crater on Bennu’s northern hemisphere. The size of a small parking lot, the site Nightingale site is one of the few relatively clear spots on this unexpectedly boulder-covered space rock.

    “This was an incredible feat – and today we’ve advanced both science and engineering and our prospects for future missions to study these mysterious ancient storytellers of the solar system,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “A piece of primordial rock that has witnessed our solar system’s entire history may now be ready to come home for generations of scientific discovery, and we can’t wait to see what comes next.”

    “After over a decade of planning, the team is overjoyed at the success of today’s sampling attempt,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. “Even though we have some work ahead of us to determine the outcome of the event – the successful contact, the TAGSAM gas firing, and back-away from Bennu are major accomplishments for the team. I look forward to analyzing the data to determine the mass of sample collected.”

    All spacecraft telemetry data indicates the TAG event executed as expected. However, it will take about a week for the OSIRIS-REx team to confirm how much sample the spacecraft collected.

    Real-time data indicates the TAGSAM successfully contacted the surface and fired a burst of nitrogen gas. The gas should have stirred up dust and pebbles on Bennu’s surface, some of which should have been captured in the TAGSAM sample collection head. OSIRIS-REx engineers also confirmed that shortly after the spacecraft made contact with the surface, it fired its thrusters and safely backed away from Bennu.

    “Today’s TAG maneuver was historic,” said Lori Glaze, Planetary Science Division director at NASA Headquarters in Washington. “The fact that we safely and successfully touched the surface of Bennu, in addition to all the other milestones this mission has already achieved, is a testament to the living spirit of exploration that continues to uncover the secrets of the solar system.”

    “It’s hard to put into words how exciting it was to receive confirmation that the spacecraft successfully touched the surface and fired one of the gas bottles,” said Michael Moreau, OSIRIS-REx deputy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The team can’t wait to receive the imagery from the TAG event late tonight and see how the surface of Bennu responded to the TAG event.”

    The spacecraft carried out TAG autonomously, with pre-programmed instructions from engineers on Earth. Now, the OSIRIS-REx team will begin to assess whether the spacecraft grabbed any material, and, if so, how much; the goal is at least 60 grams, which is roughly equivalent to a full-size candy bar.

    OSIRIS-REx engineers and scientists will use several techniques to identify and measure the sample remotely. First, they’ll compare images of the Nightingale site before and after TAG to see how much surface material moved around in response to the burst of gas.

    “Our first indication of whether we were successful in collecting a sample will come on October 21 when we downlink the back-away movie from the spacecraft,” Moreau said. “If TAG made a significant disturbance of the surface, we likely collected a lot of material.”

    Next, the team will try to determine the amount of sample collected. One method involves taking pictures of the TAGSAM head with a camera known as SamCam, which is devoted to documenting the sample-collection process and determining whether dust and rocks made it into the collector head. One indirect indication will be the amount of dust found around the sample collector head. OSIRIS-REx engineers also will attempt to snap photos that could, given the right lighting conditions, show the inside of the head so engineers can look for evidence of sample inside of it.

    A couple of days after the SamCam images are analyzed, the spacecraft will attempt yet another method to measure the mass of the sample collected by determining the change in the spacecraft’s “moment of inertia,” a phrase that describes how mass is distributed and how it affects the rotation of the body around a central axis. This maneuver entails extending the TAGSAM arm out to the side of the spacecraft and slowly spinning the spacecraft about an axis perpendicular to the arm. This technique is analogous to a person spinning with one arm extended while holding a string with a ball attached to the end. The person can sense the mass of the ball by the tension in the string. Having performed this maneuver before TAG, and now after, engineers can measure the change in the mass of the collection head as a result of the sample inside.

    “We will use the combination of data from TAG and the post-TAG images and mass measurement to assess our confidence that we have collected at least 60 grams of sample,” said Rich Burns, OSIRIS-REx project manager at Goddard. “If our confidence is high, we’ll make the decision to stow the sample on October 30.”

    To store the sample, engineers will command the robotic arm to place the sample collector head into the Sample Return Capsule (SRC), located in the body of the spacecraft. The sample arm will then retract to the side of the spacecraft for the final time, the SRC will close, and the spacecraft will prepare for its departure from Bennu in March 2021 — this is the next time Bennu will be properly aligned with Earth for the most fuel-efficient return flight.

    If, however, it turns out that the spacecraft did not collect enough sample at Nightingale, it will attempt another TAG maneuver on Jan. 12, 2021. If that occurs, it will touch down at the backup site called “Osprey,” which is another relatively boulder-free area inside a crater near Bennu’s equator.

    OSIRIS-REx launched from Cape Canaveral Air Force Station in Florida Sept. 8, 2016. It arrived at Bennu Dec. 3, 2018, and began orbiting the asteroid for the first time on Dec. 31, 2018. The spacecraft is scheduled to return to Earth Sept. 24, 2023, when it will parachute the SRC into Utah’s west desert where scientists will be waiting to collect it.

    Goddard provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  19. WATCH: OSIRIS-REx Sample Collection Activities

    October 14, 2020 -

    NASA will broadcast coverage of a first for the agency as its Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission attempts to collect a sample of asteroid Bennu on Tuesday, Oct. 20, at 6:12 p.m. EDT.

    Live coverage of the spacecraft’s descent to the asteroid’s surface for its “Touch-And-Go,” or TAG, maneuver, which will be managed by Lockheed Martin Space near Denver, will begin at 5 p.m. on NASA Television and the agency’s website.

    Beginning with an orbit departure maneuver around 1:50 p.m., the full sequence of the complicated engineering feat will be covered on @OSIRISREx, and media and the public can ask questions using the hashtag #ToBennuandBack.

    In addition to the broadcast Tuesday, Oct. 20, briefings and social media activities will cover the mission and asteroid science on Monday, Oct. 19.

    OSIRIS-REx, which is about the size of a 15-passenger van, is currently orbiting the asteroid Bennu 200 million miles from Earth. Bennu contains material from the early solar system and may contain the molecular precursors to life and Earth’s oceans. The asteroid is about as tall as the Empire State Building and could potentially threaten Earth late in the next century, with a 1‐in‐2,700 chance of impacting our planet during one of its close approaches. OSIRIS-REx is now ready to take a sample of this ancient relic of our solar system and bring its stories and secrets home to Earth.

    Due to the coronavirus (COVID-19) pandemic, media participation in the news conferences will be remote. Only a limited number of media will be accommodated at Lockheed Martin. Denver-area media may contact Gary Napier at gary.p.napier@lmco.com for more information. For the protection of Lockheed Martin flight operations employees, the OSIRIS-REx mission operations facilities will remain closed to all media throughout these events.

    Full mission coverage and participants (all times Eastern):

    Monday, October 19

    1 p.m. – Asteroid Science and Planetary Defense media teleconference with the following participants:

    • Lori Glaze, Planetary Science Division director, NASA Headquarters, Washington
    • Hal Levison, Lucy mission principal investigator, Southwest Research Institute, Boulder, Colorado
    • Lindy Elkins-Tanton, Psyche mission principal investigator, Arizona State University, Tempe
    • Andrea Riley, DART mission program executive, NASA Headquarters
    • Jamie Elsila Cook, co-investigator for the NASA Astrobiology Institute at the Goddard Center for Astrobiology and OSIRIS-REx asteroid sample return science team collaborator

    For dial-in information, media should contact Alana Johnson at alana.r.johnson@nasa.gov no later than 11 a.m. Oct. 19.

    3 p.m. – OSIRIS-REx Science and Engineering televised briefing with the following participants:

    • Thomas Zurbuchen, associate administrator, Science Mission Directorate, NASA Headquarters, Washington
    • Lori Glaze, Planetary Science Division director, NASA Headquarters
    • Heather Enos, OSIRIS-REx deputy principal investigator, University of Arizona, Tucson
    • Kenneth Getzandanner, OSIRIS-REx flight dynamics manager, NASA’s Goddard Space Flight Center, Greenbelt, Maryland
    • Beth Buck, OSIRIS-REx mission operations program manager, Lockheed Martin Space, Littleton, Colorado

    For phone bridge information, media should contact Lonnie Shekhtman at lonnie.shekhtman@nasa.gov no later than 1 p.m. Monday, Oct. 19.

    Tuesday, October 20

    1:20 to 6:30 p.m. – Live stream animation displaying OSIRIS-REx’s sample collection activities in real time. The animation commences with the spacecraft’s slew into position for the Orbit Departure Maneuver and runs through the entire sequence of TAG events, concluding after the spacecraft’s back-away burn. Event will be broadcast on the mission’s website.

    5 to 6:30 p.m. – Live broadcast from Lockheed Martin of OSIRIS-REx’s descent to the surface of Bennu and attempt at sample collection.

    Hosted by Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, and Michelle Thaller, science communicator at Goddard, the broadcast will cover milestones in the last 90 minutes leading up to TAG and spacecraft back-away. It will include perspectives from team members and science leaders about the mission’s challenges and accomplishments.

    A clean feed of the Mission Support Area during TAG is planned to run on NASA’s media channel.

    Wednesday, October 21

    5 p.m. – Post-sampling news conference – and release of new images – with the following participants:

    • Dante Lauretta, OSIRIS-REx principal investigator, University of Arizona, Tucson
    • Rich Burns, OSIRIS-REx project manager, NASA’s Goddard Space Flight Center in Greenbelt, Maryland
    • Sandra Freund, OSIRIS-REx mission operations manager, Lockheed Martin Space, Littleton, Colorado

    For phone bridge information, media should contact Lonnie Shekhtman at lonnie.shekhtman@nasa.gov no later than 1 p.m. Oct. 21.

    6:15 to 6:45 p.m. – A NASA Science Live episode will air with team members answering live questions from the public about TAG, OSIRIS-REx, and asteroid science. Use #ToBennuAndBack to participate.

    NASA Social

    NASA also will host a #ToBennuAndBack Virtual NASA Social. RSVP to the Facebook event for social media updates.

    NASA Social participants will get a chance to:

    • Connect virtually with like-minded space enthusiasts as we prepare for TAG
    • Receive a NASA Social badge to share online or print at home
    • Virtually tour the asteroid Bennu
    • Access the broadcast and other activities around TAG

    By applying to the group, participants are explicitly agreeing to the group’s rules as set forth by NASA. All membership questions must be answered to be accepted to the group.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space near Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

    For more information on the OSIRIS-REx mission, visit:

    https://www.nasa.gov/osiris-rex

    The OSIRIS-REx press kit is available at:

    https://www.asteroidmission.org/press-kit/

     

  20. NASA’s OSIRIS-REx Unlocks More Secrets from Asteroid Bennu

    October 8, 2020 -

    NASA’s first asteroid sample return mission now knows much more about the material it’ll be collecting in just a few weeks. In a special collection of six papers published today in the journals Science and Science Advances, scientists on the OSIRIS-REx mission present new findings on asteroid Bennu’s surface material, geological characteristics, and dynamic history. They also suspect that the delivered sample of Bennu may be unlike anything we have in the meteorite collection on Earth.

    NASA’s OSIRIS-REx mission created these images using false-color Red-Green-Blue (RGB) composites of asteroid Bennu. A 2D map and spacecraft imagery were overlaid on a shape model of the asteroid to create these false-color composites. In these composites, spectrally average and bluer than average terrain looks blue, surfaces that are redder than average appear red. Bright green areas correspond to the instances of a mineral pyroxene, which likely came from a different asteroid, Vesta. Black areas near the poles indicate no data. Credit: NASA/Goddard/University of Arizona

    These discoveries complete the OSIRIS-REx mission’s pre–sample collection science requirements and offer insight into the sample of Bennu that scientists will study for generations to come.

    One of the papers, led by Amy Simon from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, shows that carbon-bearing, organic material is widespread on the asteroid’s surface, including at the mission’s primary sample site, Nightingale, where OSIRIS-REx will make its first sample collection attempt on October 20. These findings indicate that hydrated minerals and organic material will likely be present in the collected sample.

    This organic matter may contain carbon in a form often found in biology or in compounds associated with biology. Scientists are planning detailed experiments on these organic molecules and expect that the returned sample will help answer complex questions about the origins of water and life on Earth.

    “The abundance of carbon-bearing material is a major scientific triumph for the mission. We are now optimistic that we will collect and return a sample with organic material – a central goal of the OSIRIS-REx mission,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson.

    Authors of the special collection have also determined that carbonate minerals make up some of the asteroid’s geological features. Carbonate minerals often precipitate from hydrothermal systems that contain both water and carbon dioxide. A number of Bennu’s boulders have bright veins that appear to be made of carbonate – some of which are located near the Nightingale crater, meaning that carbonates might be present in the returned sample.

    The study of the carbonates found on Bennu was led by Hannah Kaplan, from Goddard. These findings have allowed scientists to theorize that Bennu’s parent asteroid likely had an extensive hydrothermal system, where water interacted with and altered the rock on Bennu’s parent body. Although the parent body was destroyed long ago, we’re seeing evidence of what that watery asteroid once looked like here – in its remaining fragments that make up Bennu. Some of these carbonate veins in Bennu’s boulders measure up to a few feet long and several inches thick, validating that an asteroid-scale hydrothermal system of water was present on Bennu’s parent body.

    During fall 2019, NASA’s OSIRIS-REx spacecraft captured this image, which shows one of asteroid Bennu’s boulders with a bright vein that appears to be made of carbonate. The image within the circle (lower right) shows a focused view of the vein. Credit: NASA/Goddard/University of Arizona

    Scientists made another striking discovery at site Nightingale: its regolith has only recently been exposed to the harsh space environment, meaning that the mission will collect and return some of the most pristine material on the asteroid. Nightingale is part of a population of young, spectrally red craters identified in a study led by Dani DellaGiustina at the University of Arizona. Bennu’s “colors” (variations in the slope of the visible-wavelength spectrum) are much more diverse than originally anticipated. This diversity results from a combination of different materials inherited from Bennu’s parent body and different durations of exposure to the space environment.

    This paper’s findings are a major milestone in an ongoing debate in the planetary science community – how primitive asteroids like Bennu change spectrally as they are exposed to “space weathering” processes, such as bombardment by cosmic rays and solar wind. While Bennu appears quite black to the naked eye, the authors illustrate the diversity of Bennu’s surface by using false-color renderings of multispectral data collected by the MapCam camera. The freshest material on Bennu, such as that found at the Nightingale site, is spectrally redder than average and thus appears red in these images. Surface material turns vivid blue when it has been exposed to space weathering for an intermediate period of time. As the surface material continues to weather over long periods of time, it ultimately brightens across all wavelengths, becoming a less intense blue – the average spectral color of Bennu.

    The paper by DellaGiustina et al. also distinguishes two main types of boulders on Bennu’s surface: dark and rough, and (less commonly) bright and smooth. The different types may have formed at different depths in the parent asteroid of Bennu.

    Not only do the boulder types differ visually, they also have their own unique physical properties. The paper led by Ben Rozitis from The Open University in the UK shows that the dark boulders are weaker and more porous, whereas the bright boulders are stronger and less porous. The bright boulders also host the carbonates identified by Kaplan and crew, suggesting that the precipitation of carbonate minerals in cracks and pore spaces may be responsible for their increased strength.

    However, both boulder types are weaker than scientists expected. Rozitis and colleagues suspect that Bennu’s dark boulders (the weaker, more porous, and more common type) would not survive the journey through Earth’s atmosphere. It’s therefore likely that the returned samples of asteroid Bennu will provide a missing link for scientists, as this type of material is not currently represented in meteorite collections.

    Bennu is a diamond-shaped pile of rubble floating in space, but there’s more to it than meets the eye. Data obtained by the OSIRIS-REx Laser Altimeter (OLA) – a science instrument contributed by the Canadian Space Agency – have allowed the mission team to develop a 3D digital terrain model of the asteroid that, at 20 cm resolution, is unprecedented in detail and accuracy. In this paper, led by Michael Daly of York University, scientists explain how detailed analysis of the asteroid’s shape revealed ridge-like mounds on Bennu that extend from pole-to-pole, but are subtle enough that they could be easily missed by the human eye. Their presence has been hinted at before, but their full pole-to-pole extents only became clear when the northern and southern hemispheres were split apart in the OLA data for comparison.

    The digital terrain model also shows that Bennu’s northern and southern hemispheres have different shapes. The southern hemisphere appears to be smoother and rounder, which the scientists believe is a result of loose material getting trapped by the region’s numerous large boulders.

    Another paper in the special collection, led by Daniel Scheeres of University of Colorado Boulder, examines the gravity field of Bennu, which has been determined by tracking the trajectories of the OSIRIS-REx spacecraft and the particles that are naturally ejected from Bennu’s surface. The use of particles as gravity probes is fortuitous. Prior to the discovery of particle ejection on Bennu in 2019, the team was concerned about mapping the gravity field to the required precision using only spacecraft tracking data. The natural supply of dozens of mini gravity probes allowed the team to vastly exceed their requirements and gain unprecedented insight into the asteroid interior.

    The reconstructed gravity field shows that the interior of Bennu is not uniform. Instead, there are pockets of higher and lower density material inside the asteroid. It’s as if there is a void at its center, within which you could fit a couple of football fields. In addition, the bulge at Bennu’s equator is under-dense, suggesting that Bennu’s rotation is lofting this material.

    All six publications in the special collection use global and local datasets collected by the OSIRIS-REx spacecraft from Feb. through Oct. 2019. The special collection underscores that sample return missions like OSIRIS-REx are essential to fully understanding the history and evolution of our Solar System.

    The mission is less than two weeks away from fulfilling its biggest goal – collecting a piece of a pristine, hydrated, carbon-rich asteroid. OSIRIS-REx will depart Bennu in 2021 and deliver the sample to Earth on Sep. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  21. OSIRIS-REx Begins its Countdown to TAG

    September 24, 2020 -

    A historic moment is on the horizon for NASA’s OSIRIS-REx mission. In just a few weeks, the robotic OSIRIS-REx spacecraft will descend to asteroid Bennu’s boulder-strewn surface, touch down for a few seconds and collect a sample of the asteroid’s rocks and dust – marking the first time NASA has grabbed pieces of an asteroid, which will be returned to Earth for study.

    Artist’s conception of NASA’s OSIRIS-REx spacecraft collecting a sample from the asteroid Bennu. Credit: NASA/Goddard/University of Arizona

    On Oct. 20, the mission will perform the first attempt of its Touch-And-Go (TAG) sample collection event. This series of maneuvers will bring the spacecraft down to site Nightingale, a rocky area 52 ft (16 m) in diameter in Bennu’s northern hemisphere, where the spacecraft’s robotic sampling arm will attempt to collect a sample. Site Nightingale was selected as the mission’s primary sample site because it holds the greatest amount of unobstructed fine-grained material, but the region is surrounded by building-sized boulders. During the sampling event, the spacecraft, which is the size of a large van, will attempt to touch down in an area that is only the size of a few parking spaces, and just a few steps away from some of these large boulders.

    During the 4.5-hour sample collection event, the spacecraft will perform three separate maneuvers to reach the asteroid’s surface. The descent sequence begins with OSIRIS-REx firing its thrusters for an orbit departure maneuver to leave its safe-home orbit approximately 2,500 feet (770 meters) from Bennu’s surface. After traveling four hours on this downward trajectory, the spacecraft performs the “Checkpoint” maneuver at an approximate altitude of 410 ft (125 m). This thruster burn adjusts OSIRIS-REx’s position and speed to descend steeply toward the surface. About 11 minutes later, the spacecraft performs the “Matchpoint” burn at an approximate altitude of 177 ft (54 m), slowing its descent and targeting a path to match the asteroid’s rotation at the time of contact. The spacecraft then descends to the surface, touches down for less than sixteen seconds and fires one of its three pressurized nitrogen bottles. The gas agitates and lifts Bennu’s surface material, which is then caught in the spacecraft’s collector head. After this brief touch, OSIRIS-REx fires its thrusters to back away from Bennu’s surface and navigates to a safe distance from the asteroid.

    After the orbit departure maneuver, the spacecraft undertakes a sequence of reconfigurations to prepare for sampling. First, OSIRIS-REx extends its robotic sampling arm – the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – from its folded storage position out to the sample collection position. The spacecraft’s two solar panels then move into a “Y-wing” configuration over the spacecraft’s body, which positions them safely up and away from the asteroid’s surface during touch down. This configuration also places the spacecraft’s center of gravity directly over the TAGSAM collector head, which is the only part of the spacecraft that will contact Bennu’s surface during the sample collection event.

    Because the spacecraft and Bennu are approximately 207 million miles (334 million km) from Earth during TAG, it will take about 18.5 minutes for signals to travel between them. This time lag prevents the live commanding of flight activities from the ground during the TAG event, so the spacecraft is designed to perform the entire sample collection sequence autonomously. Prior to the event’s start, the OSIRIS-REx team will uplink all of the commands to the spacecraft and then send a “GO” command to begin.

    This view of sample site Nightingale on asteroid Bennu is a mosaic of 345 images collected by NASA’s OSIRIS-REx spacecraft on March 3. The image is overlaid with a graphic of the OSIRIS-REx spacecraft to illustrate the targeted touchdown spot. The mosaic is rotated so that Bennu’s east is at the top of the image. Credit: NASA/Goddard/University of Arizona

    To autonomously navigate to site Nightingale, OSIRIS-REx uses the Natural Feature Tracking (NFT) navigation system. The spacecraft begins collecting navigation images about 90 minutes after orbit departure. It then compares these real-time images to an onboard image catalog, using identified surface features to make sure that it’s on the right course toward the site. As the spacecraft approaches the surface, OSIRIS-REx updates the Checkpoint and Matchpoint maneuvers based on the NFT’s estimate of the spacecraft’s position and velocity. OSIRIS-REx continues to use the NFT estimates as it descends to the surface after the Matchpoint maneuver to monitor its position and descent rate. The spacecraft will autonomously abort should its trajectory vary outside of predefined limits.

    To ensure that the spacecraft touches down on a safe area that avoids the region’s many boulders, the navigation system is equipped with a hazard map of site Nightingale, which delineates areas within the sample site that could potentially harm the spacecraft. If the spacecraft’s NFT system detects that it is on course to touch one of these hazardous zones, the spacecraft will autonomously wave off its approach once it reaches an altitude of 16 ft (5 m). This keeps the spacecraft safe and allows for a subsequent sample collection attempt at a future date.

    As the spacecraft performs each event in the sample collection sequence, it will send telemetry updates back to the OSIRIS-REx team, albeit at an extremely slow data rate. The team will monitor the telemetry during the excursion and will be able to confirm that the spacecraft has successfully touched down on Bennu’s surface soon after TAG occurs. The images and other science data collected during the event will be downlinked after the spacecraft has backed away from the asteroid and can point its larger antenna back to Earth to transmit at higher communication rates.

    OSIRIS-REx is charged with collecting at least 2 oz. (60 grams) of Bennu’s rocky material to deliver back to Earth – the largest sample return from space since the Apollo program – and the mission developed two methods to verify that this sample collection occurred. On Oct. 22, OSIRIS-REx’s SamCam camera will capture images of the TAGSAM head to see whether it contains Bennu’s surface material. The spacecraft will also perform a spin maneuver on Oct. 24 to determine the mass of collected material. If these measures show successful collection, the decision will be made to place the sample in the Sample Return Capsule (SRC) for return to Earth. If sufficient sample has not been collected from Nightingale, the spacecraft has onboard nitrogen charges for two more attempts. A TAG attempt at the back-up Osprey site would be made no earlier than January 2021.

    The mission team has spent the last several months preparing for the sample collection event while maximizing remote work as part of its COVID-19 response. On the day of TAG, a limited number of team members will monitor the spacecraft from Lockheed Martin Space’s Mission Support Area, taking appropriate safety precautions. Other members of the team will also be at other locations on-site to cover the event, while also observing safety protocols.

    The spacecraft is scheduled to depart Bennu in 2021 and it will deliver the collected sample to Earth on Sep. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

    For graphics from the Sept. 24 media telecon, go to: https://svs.gsfc.nasa.gov/13724

  22. NASA’s OSIRIS-REx to Asteroid Bennu: “You’ve got a little Vesta on you…”

    September 21, 2020 -

    In an interplanetary faux pas, it appears some pieces of asteroid Vesta ended up on asteroid Bennu, according to observations from NASA’s OSIRIS-REx spacecraft. The new result sheds light on the intricate orbital dance of asteroids and on the violent origin of Bennu, which is a “rubble pile” asteroid that coalesced from the fragments of a massive collision.

    We found six boulders ranging in size from 5 to 14 feet (about 1.5 to 4.3 meters) scattered across Bennu’s southern hemisphere and near the equator,” said Daniella DellaGiustina of the Lunar & Planetary Laboratory, University of Arizona, Tucson. “These boulders are much brighter than the rest of Bennu and match material from Vesta.”

    During spring 2019, NASA’s OSIRIS-REx spacecraft captured these images, which show fragments of asteroid Vesta present on asteroid Bennu’s surface. The bright boulders (circled in the images) are pyroxene-rich material from Vesta. Some bright material appear to be individual rocks (left) while others appear to be clasts within larger boulders (right). Credit: NASA/Goddard/University of Arizona

    “Our leading hypothesis is that Bennu inherited this material from its parent asteroid after a vestoid (a fragment from Vesta) struck the parent,” said Hannah Kaplan of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Then, when the parent asteroid was catastrophically disrupted, a portion of its debris accumulated under its own gravity into Bennu, including some of the pyroxene from Vesta.”

    DellaGiustina and Kaplan are primary authors of a paper on this research appearing in Nature Astronomy September 21.

    The unusual boulders on Bennu first caught the team’s eye in images from the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) Camera Suite (OCAMS). They appeared extremely bright, with some almost ten times brighter than their surroundings. They analyzed the light from the boulders using the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) instrument to get clues to their composition. A spectrometer separates light into its component colors. Since elements and compounds have distinct, signature patterns of bright and dark across a range of colors, they can be identified using a spectrometer. The signature from the boulders was characteristic of the mineral pyroxene, similar to what is seen on Vesta and the vestoids, smaller asteroids that are fragments blasted from Vesta when it sustained significant asteroid impacts. 

    Of course it’s possible that the boulders actually formed on Bennu’s parent asteroid, but the team thinks this is unlikely based on how pyroxene typically forms. The mineral typically forms when rocky material melts at high-temperature. However, most of Bennu is composed of rocks containing water-bearing minerals, so it (and its parent) couldn’t have experienced very high temperatures. Next, the team considered localized heating, perhaps from an impact. An impact needed to melt enough material to create large pyroxene boulders would be so significant that it would have destroyed Bennu’s parent-body. So, the team ruled out these scenarios, and instead considered other pyroxene-rich asteroids that might have implanted this material to Bennu or its parent.

    Observations reveal it’s not unusual for an asteroid to have material from another asteroid splashed across its surface. Examples include dark material on crater walls seen by the Dawn spacecraft at Vesta, a black boulder seen by the Hayabusa spacecraft on Itokawa, and very recently, material from S-type asteroids observed by Hayabusa2 at Ryugu. This indicates many asteroids are participating in a complex orbital dance that sometimes results in cosmic mashups.

    As asteroids move through the solar system, their orbits can be altered in many ways, including the pull of gravity from planets and other objects, meteoroid impacts, and even the slight pressure from sunlight. The new result helps pin down the complex journey Bennu and other asteroids have traced through the solar system.

    Based on its orbit, several studies indicate Bennu was delivered from the inner region of the Main Asteroid Belt via a well-known gravitational pathway that can take objects from the inner Main Belt to near-Earth orbits. There are two inner Main Belt asteroid families (Polana and Eulalia) that look like Bennu: dark and rich in carbon, making them likely candidates for Bennu’s parent. Likewise, the formation of the vestoids is tied to the formation of the Veneneia and Rheasilvia impact basins on Vesta, at roughly about two billion years ago and approximately one billion years ago, respectively.

    “Future studies of asteroid families, as well as the origin of Bennu, must reconcile the presence of Vesta-like material as well as the apparent lack of other asteroid types. We look forward to the returned sample, which hopefully contains pieces of these intriguing rock types,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. “This constraint is even more compelling given the finding of S-type material on asteroid Ryugu. This difference shows the value in studying multiple asteroids across the solar system.”

    The spacecraft is going to make its first attempt to sample Bennu in October and return it to Earth in 2023 for detailed analysis. The mission team closely examined four potential sample sites on Bennu to determine their safety and science value before making a final selection in December 2019. DellaGiustina and Kaplan’s team thinks they might find smaller pieces of Vesta in images from these close-up studies.

    The research was funded by the NASA New Frontiers Program. The primary authors acknowledge significant collaboration with the French space agency CNES on this paper. NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. The late Michael Drake of the University of Arizona pioneered the study of vestoid meteorites and was the first principal investigator for OSIRIS-REx. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. NASA is exploring our Solar System and beyond, uncovering worlds, stars, and cosmic mysteries near and far with our powerful fleet of space and ground-based missions.

  23. Where Rocks Come Alive: OSIRIS-REx Observes an Asteroid in Action

    By Daniel Stolte

    September 9, 2020 -

    It’s 5 o’clock somewhere – and while here on Earth, “happy hour” is commonly associated with winding down and the optional cold beverage, that’s when things get going on Bennu, the destination asteroid of the University of Arizona-led OSIRIS-REx mission.

    Using data collected by NASA’s OSIRIS-REx mission, this animation shows the trajectories of particles after their emission from asteroid Bennu’s surface. The animation emphasizes the four largest particle ejection events detected at Bennu from December 2018 through September 2019. Additional particles, some with lifetimes of several days, that are not related to the ejections are also visible. Credit: M. Brozovic/JPL-Caltech/NASA/University of Arizona

    In a special collection of research papers published Sep. 9 in the Journal of Geophysical Research: Planets, the OSIRIS-REx science team reports detailed observations that reveal Bennu is shedding material on a regular basis. The OSIRIS-REx spacecraft has provided planetary scientists with the opportunity to observe such activity at close range for the first time ever, and Bennu’s active surface underscores an emerging picture in which asteroids are quite dynamic worlds.

    The publications provide the first in-depth look at the nature of Bennu’s particle ejection events, detail the methods used to study these phenomena, and discuss the likely mechanisms at work that cause the asteroid to release pieces of itself into space.

    The first observation of particles popping off the asteroid’s surface was made in January 2019, mere days after the spacecraft arrived at Bennu. This event may have gone completely unnoticed were it not for the keen eye of the mission’s lead astronomer and UArizona’s Lunar and Planetary Laboratory scientist, Carl Hergenrother, one of the lead authors of the collection and its introduction.

    Much like ocean-going explorers in centuries past, the space probe relies on stars to fix its position in space and remain on course during its years-long voyage across space. A specialized navigation camera onboard the spacecraft takes repeat images of background stars. By cross-referencing the constellations the spacecraft “sees” with programmed star charts, course corrections can be made as necessary.

    Hergenrother was poring over these images that the spacecraft had beamed back to Earth when something caught his attention. The images showed the asteroid silhouetted against a black sky dotted with many stars – except there seemed to be too many.

    “I was looking at the star patterns in these images and thought, ‘huh, I don’t remember that star cluster,'” Hergenrother said. “I only noticed it because there were 200 dots of light where there should be about 10 stars. Other than that, it looked to be just a dense part of the sky.”

    A closer inspection and an application of image-processing techniques unearthed the mystery: the “star cluster” was in fact a cloud of tiny particles that had been ejected from the asteroid’s surface. Follow-up observations made by the spacecraft revealed the telltale streaks typical of objects moving across the frame, setting them apart from the background stars that appear stationary due to their enormous distances.

    “We thought that Bennu’s boulder-covered surface was the wild card discovery at the asteroid, but these particle events definitely surprised us,” said Dante Lauretta, OSIRIS-REx principal investigator and professor at LPL. “We’ve spent the last year investigating Bennu’s active surface, and it’s provided us with a remarkable opportunity to expand our knowledge of how active asteroids behave.”

    Since arriving at the asteroid, the team has observed and tracked more than 300 particle ejection events on Bennu. According to the authors, some particles escape into space, others briefly orbit the asteroid, and most fall back onto its surface after being launched. Ejections most often occur during Bennu’s local two-hour afternoon and evening timeframe.

    The spacecraft is equipped with a sophisticated set of electronic eyes – the Touch-and-Go Camera Suite, or TAGCAMS. Although its primary purpose is to assist in spacecraft navigation, TAGCAMS has now been placed into active duty spotting any particles in the vicinity of the asteroid.

    Using software algorithms developed at UArizona’s Catalina Sky Survey, which specializes in discovering and tracking near-Earth asteroids by detecting their motion against background stars, the OSIRIS-REx team found the largest particles erupting from Bennu to be about 6 centimeters (2 inches) in diameter. Due to their small size and low velocities – this is like a shower of tiny pebbles in super-slo-mo – the mission team does not deem the particles a threat to the spacecraft.

    “Space is so empty that even when the asteroid is throwing off hundreds of particles, as we have seen in some events, the chances of one of those hitting the spacecraft is extremely small,” Hergenrother said, “and even if that were to happen, the vast majority of them are not fast or large enough to cause damage.”

    During a number of observation campaigns between January and September 2019 dedicated to detecting and tracking mass ejected from the asteroid, a total of 668 particles were studied, with the vast majority measuring between 0.5 and 1 centimeters (0.2-0.4 inches), and moving at about 20 centimeters (8 inches) per second, about as fast – or slow – as a beetle scurrying across the ground. In one instance, a speedy outlier was clocked at about 3 meters (9.8 feet) per second.

    On average, the authors observed one to two particles kicked up per day, with much of the material falling back onto the asteroid. Add to that the small particle sizes, and the mass loss becomes minimal, Hergenrother explained.

    This view of asteroid Bennu ejecting particles from its surface on January 19 was created by combining two images taken by the NavCam 1 imager onboard NASA’s OSIRIS-REx spacecraft: a short exposure image (1.4 ms), which shows the asteroid clearly, and a long exposure image (5 sec), which shows the particles clearly. Other image processing techniques were also applied, such as cropping and adjusting the brightness and contrast of each layer. Credit: NASA/Goddard/University of Arizona/Lockheed Martin

    “To give you an idea, all of those 200 particles we observed during the first event after arrival would fit on a 4-inch x 4-inch tile,” he said. “The fact that we can even see them is a testament to the capabilities of our cameras.”

    The authors investigated various mechanisms that could cause these phenomena, including released water vapor, impacts by small space rocks known as meteoroids and rocks cracking from thermal stress. The two latter mechanisms were found to be the most likely driving forces, confirming predictions about Bennu’s environment based on ground observations preceding the space mission.

    As Bennu completes one rotation every 4.3 hours, boulders on its surface are exposed to a constant thermo-cycling as they heat during the day and cool during the night. Over time, the rocks crack and break down, and eventually particles may be thrown from the surface. The fact that particle ejections were observed with greater frequency during late afternoon, when the rocks heat up, suggests thermal cracking is a major driver. The timing of the events is also consistent with the timing of meteoroid impacts, indicating that these small impacts could be throwing material from the surface. Either, or both, of these processes could be driving the particle ejections, and because of the asteroid’s microgravity environment, it doesn’t take much energy to launch an object from Bennu’s surface.

    Of the particles the team observed, some had suborbital trajectories, keeping them aloft for a few hours before they settled back down, while others fly off the asteroid to go into their own orbits around the sun.

    In one instance, the team tracked one particle as it circled the asteroid for almost a week. The spacecraft’s cameras even witnessed a ricochet, according to Hergenrother.

    “One particle came down, hit a boulder and went back into orbit,” he said. “If Bennu has this kind of activity, then there is a good chance all asteroids do, and that is really exciting.”

    As Bennu continues to unveil itself, the OSIRIS-REx team continues to discover that this small world is glowingly complex. These findings could serve as a cornerstone for future planetary missions that seek to better characterize and understand how these small bodies behave and evolve.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  24. A Successful Second Rehearsal Puts NASA’s OSIRIS-REx on a Path to Sample Collection

    August 12, 2020 -

    NASA’s first asteroid-sampling spacecraft just completed its second successful sample collection rehearsal and is now ready for the main event – touching down on asteroid Bennu’s surface in October. Yesterday, the OSIRIS-REx spacecraft performed its final practice run of the sampling sequence, reaching an approximate altitude of 131 feet (40 meters) over sample site Nightingale before executing a back-away burn. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater in Bennu’s northern hemisphere.

    Captured on Aug. 11 during the second rehearsal of the OSIRIS-REx mission’s sample collection event, this series of images shows the SamCam imager’s field of view as the NASA spacecraft approaches asteroid Bennu’s surface. The rehearsal brought the spacecraft through the first three maneuvers of the sampling sequence to a point approximately 131 feet (40 meters) above the surface, after which the spacecraft performed a back-away burn. Credit: NASA/Goddard/University of Arizona

    The approximately four-hour “Matchpoint” rehearsal took the spacecraft through the first three of the sampling sequence’s four maneuvers: the orbit departure burn, the “Checkpoint” burn and the Matchpoint burn. Checkpoint is the point where the spacecraft autonomously checks its position and velocity before adjusting its trajectory down toward the event’s third maneuver. Matchpoint is the moment when the spacecraft matches Bennu’s rotation in order to fly in tandem with the asteroid surface, directly above the sample site, before touching down on the targeted spot.

    Four hours after departing its 0.6-mile (1-km) safe-home orbit, OSIRIS-REx performed the Checkpoint maneuver at an approximate altitude of 410 feet (125 meters) above Bennu’s surface. From there, the spacecraft continued to descend for another eight minutes to perform the Matchpoint burn. After descending on this new trajectory for another three minutes, the spacecraft reached an altitude of approximately 131 ft (40 m) – the closest the spacecraft has ever been to Bennu – and then performed a back-away burn to complete the rehearsal.

    During the rehearsal, the spacecraft successfully deployed its sampling arm, the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), from its folded, parked position out to the sample collection configuration. Additionally, some of the spacecraft’s instruments collected science and navigation images and made spectrometry observations of the sample site, as will occur during the sample collection event. These images and science data were downlinked to Earth after the event’s conclusion.

    Because the spacecraft and Bennu are currently about 179 million miles (288 million km) from Earth, it takes approximately 16 minutes for the spacecraft to receive the radio signals used to command it. This time lag prevented live commanding of flight activities from the ground during the rehearsal. As a result, the spacecraft performed the entire rehearsal sequence autonomously. Prior to the rehearsal’s start, the OSIRIS-REx team uplinked all of the event’s commands to the spacecraft and then provided the “Go” command to begin the event. The actual sample collection event in October will be conducted the same way.

    This second rehearsal provided the mission team with practice navigating the spacecraft through the first three maneuvers of the sampling event and with an opportunity to verify that the spacecraft’s imaging, navigation and ranging systems operated as expected during the first part of the descent sequence.

    Matchpoint rehearsal also confirmed that OSIRIS-REx’s Natural Feature Tracking (NFT) guidance system accurately estimated the spacecraft’s trajectory after the Matchpoint burn, which is the final maneuver before the sample collection head contacts Bennu’s surface. This rehearsal was also the first time that the spacecraft’s on-board hazard map was employed. The hazard map delineates areas that could potentially harm the spacecraft. If the spacecraft detects that it is on course to touch a hazardous area, it will autonomously back-away once it reaches an altitude of 16 ft (5 m). While OSIRIS-REx did not fly that low during the rehearsal, it did employ the hazard map to assess whether its predicted touchdown trajectory would have avoided surface hazards, and found that the spacecraft’s path during the rehearsal would have allowed for a safe touchdown on sample site Nightingale.

    During the last minutes of the spacecraft’s descent, OSIRIS-REx also collected new, high-resolution navigation images for the NFT guidance system. These detailed images of Bennu’s landmarks will be used for the sampling event, and will allow the spacecraft to accurately target a very small area.

    “Many important systems were exercised during this rehearsal – from communications, spacecraft thrusters, and most importantly, the onboard Natural Feature Tracking guidance system and hazard map,” said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson. “Now that we’ve completed this milestone, we are confident in finalizing the procedures for the TAG event. This rehearsal confirmed that the team and all of the spacecraft’s systems are ready to collect a sample in October.”

    The mission team has spent the last several months preparing for Matchpoint rehearsal while maximizing remote work as part of the COVID-19 response. On the day of rehearsal, a limited number of personnel monitored the spacecraft’s telemetry from Lockheed Martin Space’s facility, NASA’s Goddard Space Flight Center and the University of Arizona, taking appropriate safety precautions, while the rest of the team performed their roles remotely.

    The spacecraft will travel all the way to the asteroid’s surface during its first sample collection attempt, scheduled for Oct. 20. During this event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface for several seconds, fire a charge of pressurized nitrogen to disturb the surface and collect a sample before the spacecraft backs away. The spacecraft is scheduled to return the sample to Earth on Sept. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  25. NASA’s OSIRIS-REx Is One Rehearsal Away from Touching Asteroid Bennu

    August 6, 2020 -

    NASA’s first asteroid sampling spacecraft is making final preparations to grab a sample from asteroid Bennu’s surface. Next week, the OSIRIS-REx mission will conduct a second rehearsal of its touchdown sequence, practicing the sample collection activities one last time before touching down on Bennu this fall.

    This artist’s concept shows the trajectory and configuration of NASA’s OSIRIS-REx spacecraft during Matchpoint rehearsal, which is the final time the mission will practice the initial steps of the sample collection sequence before touching down on asteroid Bennu. Credit: NASA/Goddard/University of Arizona

    On Aug. 11, the mission will perform its “Matchpoint” rehearsal – the second practice run of the Touch-and-Go (TAG) sample collection event. The rehearsal will be similar to the Apr. 14 “Checkpoint” rehearsal, which practiced the first two maneuvers of the descent, but this time the spacecraft will add a third maneuver, called the Matchpoint burn, and fly even closer to sample site Nightingale – reaching an altitude of approximately 131 ft (40 m) – before backing away from the asteroid.

    This second rehearsal will be the first time the spacecraft executes the Matchpoint maneuver to then fly in tandem with Bennu’s rotation. The rehearsal also gives the team a chance to become more familiar navigating the spacecraft through all of the descent maneuvers, while verifying that the spacecraft’s imaging, navigation and ranging systems operate as expected during the event.

    During the descent, the spacecraft fires its thrusters three separate times to make its way down to the asteroid’s surface. The spacecraft will travel at an average speed of around 0.2 mph (0.3 kph) during the approximately four-hour excursion. Matchpoint rehearsal begins with OSIRIS-REx firing its thrusters to leave its 0.5-mile (870-m) safe-home orbit. The spacecraft then extends its robotic sampling arm – the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – from its folded, parked position out to the sample collection configuration. Immediately following, the spacecraft rotates to begin collecting navigation images for the Natural Feature Tracking (NFT) guidance system. NFT allows OSIRIS-REx to autonomously navigate to Bennu’s surface by comparing an onboard image catalog with the real-time navigation images taken during descent. As the spacecraft approaches the surface, the NFT system updates the spacecraft’s predicted point of contact depending on OSIRIS-REx’s position in relation to Bennu’s landmarks.

    The spacecraft’s two solar panels then move into a “Y-wing” configuration that safely positions them up and away from the asteroid’s surface. This configuration also places the spacecraft’s center of gravity directly over the TAGSAM collector head, which is the only part of the spacecraft that will contact Bennu’s surface during the sample collection event.

    When OSIRIS-REx reaches an altitude of approximately 410 ft (125 m), it performs the Checkpoint burn and descends more steeply toward Bennu’s surface for another eight minutes. At approximately 164 ft (50 m) above the asteroid, the spacecraft fires its thrusters a third time for the Matchpoint burn. This maneuver slows the spacecraft’s rate of descent and adjusts its trajectory to match Bennu’s rotation as the spacecraft makes final corrections to target the touchdown spot. OSIRIS-REx will continue capturing images of Bennu’s landmarks for the NFT system to update the spacecraft’s trajectory for another three minutes of descent. This brings OSIRIS-REx to its targeted destination around 131 ft (40 m) from Bennu – the closest it has ever been to the asteroid. With the rehearsal complete, the spacecraft executes a back-away burn, returns its solar panels to their original position and reconfigures the TAGSAM arm back to the parked position.

    During the rehearsal, the one-way light time for signals to travel between Earth and the spacecraft will be approximately 16 minutes, which prevents the live commanding of flight activities from the ground. So prior to the rehearsal’s start, the OSIRIS-REx team will uplink all of the event’s commands to the spacecraft, allowing OSIRIS-REx to perform the rehearsal sequence autonomously after the GO command is given. Also during the event, the spacecraft’s low gain antenna will be its only antenna pointing toward Earth, transmitting data at the very slow rate of 40 bits per second. So while the OSIRIS-REx team will be able to monitor the spacecraft’s vital signs, the images and science data collected during the event won’t be downlinked until the rehearsal is complete. The team will experience these same circumstances during the actual TAG event in October.

    Following Matchpoint rehearsal, the OSIRIS-REx team will verify the flight system’s performance during the descent, including that the Matchpoint burn accurately adjusted the spacecraft’s descent trajectory for its touchdown on Bennu. Once the mission team determines that OSIRIS-REx operated as expected, they will command the spacecraft to return to its safe-home orbit around Bennu.

    The mission team has spent the last several months preparing for the Matchpoint rehearsal while maximizing remote work as part of its COVID-19 response. On the day of rehearsal, a limited number of personnel will monitor the spacecraft from Lockheed Martin Space’s facility, taking appropriate safety precautions, while the rest of the team performs their roles remotely. The mission implemented a similar protocol during the Checkpoint rehearsal in April.

    On Oct. 20, the spacecraft will travel all the way to the asteroid’s surface during its first sample collection attempt. During this event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface for approximately five seconds, fire a charge of pressurized nitrogen to disturb the surface and collect a sample before the spacecraft backs away. The spacecraft is scheduled to return the sample to Earth on Sept. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  26. NASA’s OSIRIS-REx Discovers Sunlight Can Crack Rocks on Asteroid Bennu

    June 9, 2020 -

    Asteroids don’t just sit there doing nothing as they orbit the Sun. They get bombarded by meteoroids, blasted by space radiation, and now, for the first time, scientists are seeing evidence that even a little sunshine can wear them down.

    Rocks on asteroid Bennu appear to be cracking as sunlight heats them up during the day and they cool down at night, according to images from NASA’s OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security – Regolith Explorer) spacecraft.

    This image shows a group of large boulders located just north of asteroid Bennu’s equatorial region. The boulder in the lower right shows evidence of exfoliation, where thermal fracturing likely caused small, thin layers to flake off of the boulder’s surface. Credit: NASA/Goddard/University of Arizona

    “This is the first time evidence for this process, called thermal fracturing, has been definitively observed on an object without an atmosphere,” said Jamie Molaro of the Planetary Science Institute, Tucson, Arizona, lead author of a paper appearing in Nature Communications June 9. “It is one piece of a puzzle that tells us what the surface used to be like, and what it will be like millions of years from now.”

    “Like any weathering process, thermal fracturing causes the evolution of boulders and planetary surfaces over time – from changing the shape and size of individual boulders, to producing pebbles or fine-grained regolith, to breaking down crater walls,” said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson. “How quickly this occurs relative to other weathering processes tells us how and how quickly the surface has changed.”

    Rocks expand when sunlight heats them during the day and contract as they cool down at night, causing stress that forms cracks that grow slowly over time. Scientists have thought for a while that thermal fracturing could be an important weathering process on airless objects like asteroids because many experience extreme temperature differences between day and night, compounding the stress. For example, daytime highs on Bennu can reach almost 127 degrees Celsius or about 260 degrees Fahrenheit, and nighttime lows plummet to about minus 73 degrees Celsius or nearly minus 100 degrees Fahrenheit. However, many of the telltale features of thermal fracturing are small, and before OSIRIS-REx got close to Bennu, the high-resolution imagery required to confirm thermal fracturing on asteroids didn’t exist.

    The mission team found features consistent with thermal fracturing using the spacecraft’s OSIRIS-REx Camera Suite (OCAMS), which can see features on Bennu smaller than one centimeter (almost 0.4 inches). It found evidence of exfoliation, where thermal fracturing likely caused small, thin layers (1 – 10 centimeters) to flake off of boulder surfaces. The spacecraft also produced images of cracks running through boulders in a north-south direction, along the line of stress that would be produced by thermal fracturing on Bennu.

    Other weathering processes can produce similar features, but the team’s analysis ruled them out. For example, rain and chemical activity can produce exfoliation, but Bennu has no atmosphere to produce rain. Rocks squeezed by tectonic activity can also exfoliate, but Bennu is too small for such activity. Meteoroid impacts do occur on Bennu and can certainly crack rocks, but they would not cause the even erosion of layers from boulder surfaces that were seen. Also, there’s no sign of impact craters where the exfoliation is occurring.

    Additional studies of Bennu could help determine how rapidly thermal fracturing is wearing down the asteroid, and how it compares to other weathering processes. “We don’t have good constraints yet on breakdown rates from thermal fracturing, but we can get them now that we can actually observe it for the first time in situ,” said OSIRIS-REx project scientist Jason Dworkin of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Laboratory measurements on the properties of the samples returned by the spacecraft in 2023 will help us learn more about how this process works.”

    Another area of research is how thermal fracturing affects our ability to estimate the age of surfaces. In general, the more weathered a surface is, the older it is. For example, a region with a lot of craters is likely to be older than an area with few craters, assuming impacts happen at a relatively constant rate across an object. However, additional weathering from thermal fracturing could complicate an age estimate, because thermal fracturing is going to happen at a different rate on different bodies, depending on things like their distance from the Sun, the length of their day, and the composition, structure and strength of their rocks. On bodies where thermal fracturing is efficient, then it may cause crater walls to break down and erode faster. This would make the surface look older according the cratering record, when in fact it is actually younger. Or the opposite could occur. More research on thermal fracturing on different bodies is needed to start to get a handle on this, according to Molaro.

    The research was funded by NASA’s OSIRIS-REx Participating Scientist program as well as the OSIRIS-REx mission. NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. NASA is exploring our Solar System and beyond, uncovering worlds, stars, and cosmic mysteries near and far with our powerful fleet of space and ground-based missions.

  27. Asteroids Bennu and Ryugu May Have Formed Directly From Collision in Space

    June 1, 2020 -

    Scientists with NASA’s first asteroid sample return mission, OSIRIS-REx, are gaining a new understanding of asteroid Bennu’s carbon-rich material and signature “spinning-top” shape. The team, led by the University of Arizona, has discovered that the asteroid’s shape and hydration levels provide clues to the origins and histories of this and other small bodies.

    Illustrating what scientists argue in the paper, this animation demonstrates how top-shape asteroids may have formed. This simulation shows the gravitational reaccumulation of an asteroid parent body (center) following its catastrophic disruption by an impact. The movie begins with a change in perspective to display the initial geometry of the impacted 100-km asteroid, followed by the dispersal of fragments to form separate rubble-pile asteroids. The color of each particle indicates the change in its temperature after impact, with blue being no change and dark red indicated a change of 1000 Kelvin.

    Bennu, the target asteroid for the OSIRIS-REx mission, and Ryugu, the target of the Japan Aerospace Exploration Agency’s Hayabusa2 asteroid sample return mission, are composed of fragments of larger bodies that shattered upon colliding with other objects. The small fragments reaccumulated to form an aggregate body. Bennu and Ryugu may actually have formed in this way from the same original shattered parent body. Now, scientists are looking to discover what processes led to specific characteristics of these asteroids, such as their shape and mineralogy.

    Bennu and Ryugu are both classified as “spinning-top” asteroids, which means they have a pronounced equatorial ridge. Until now, scientists thought that this shape formed as the result of thermal forces, called the YORP effect. The YORP effect increases the speed of the asteroid’s spin, and over millions of years, material near the poles could have migrated to accumulate on the equator, eventually forming a spinning-top shape – meaning that the shape would have formed relatively recently.

    However, in a new paper published in Nature Communications, scientists from the OSIRIS-REx and Hayabusa2 teams argue that the YORP effect may not explain the shape of either Bennu or Ryugu. Both asteroids have large impact craters on their equators, and their size suggests that these craters are some of Bennu’s oldest surface features. Since the craters cover the equatorial ridges, their spinning-top shapes must also have been formed much earlier.

    “Using computer simulations that model the impact that broke up Bennu’s parent body, we show that these asteroids either formed directly as top-shapes, or achieved the shape early after their formation in the main asteroid belt,” said Ronald Ballouz, co-lead author and OSIRIS-REx postdoctoral research associate at the UArizona. “The presence of the large equatorial craters on these asteroids, as seen in images returned by the spacecraft, rules out that the asteroids experienced a recent re-shaping due to the YORP effect. We would expect these craters to have disappeared with a recent YORP-induced re-shaping of the asteroid.”

    In addition to their shapes, Bennu and Ryugu also both contain water-bearing surface material in the form of clay minerals. Ryugu’s surface material is less water-rich than Bennu’s, which implies that Ryugu’s material experienced more heating at some point.

    This image shows asteroid Bennu’s spinning top shape. It was taken by the MapCam camera on NASA’s OSIRIS-REx spacecraft on April 29, from a distance of 5 miles (8 km). From the spacecraft’s vantage point, half of Bennu is sunlit and half is in shadow. The asteroid is 1,673 ft (510 m) in height – a bit taller than the Empire State Building.

    Assuming Bennu and Ryugu formed simultaneously, the paper explores two possible explanations for the different hydration levels of the two bodies based on the team’s computer simulations. One hypothesis suggests that when the parent asteroid was disrupted, Bennu formed from material closer to the original surface, while Ryugu contained more material from near the parent body’s original center. Another possible explanation for the difference in hydration levels is that the fragments experienced different levels of heating during the parent asteroid’s disruption. If this is the case, Ryugu’s source material is likely from an area near the impact point, where temperatures were higher. Bennu’s material would have come from a region that didn’t undergo as much heating, and was likely farther from the point of impact. Analysis of the returned samples and further observational analysis of the asteroids’ surfaces will provide a clearer idea of the possible shared history of the two asteroids.

    “These simulations provide valuable new insights into how Bennu and Ryugu formed,” said Dante Lauretta, OSIRIS-REx principal investigator and UArizona professor of planetary sciences. “Once we have the returned samples of these two asteroids in the lab, we may be able to further confirm these models, possibly revealing the true relationship between the two asteroids.”

    Scientists anticipate that the samples will also provide new insights into the origins, formation and evolution of other carbonaceous asteroids and meteorites. The Japan Aerospace Exploration Agency’s Hayabusa2 mission is currently making its way back to Earth, and is scheduled to deliver its samples of Ryugu late this year. The OSIRIS-REx mission will perform its first sample collection attempt at Bennu on Oct. 20 and will deliver its samples to Earth on Sep. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  28. OSIRIS-REx Performs Closest Flyover of Sample Site Osprey

    May 27, 2020 -

    NASA’s first asteroid-sampling spacecraft has had another close encounter with asteroid Bennu. Yesterday, NASA’s OSIRIS-REx spacecraft executed its lowest pass yet over sample site Osprey, taking observations from an altitude of 820 feet (250 m). Osprey, OSIRIS-REx’s backup sample collection site, is located within a crater just north of Bennu’s equator.

    To perform the five-hour flyover, the spacecraft left its 0.6-mile (1-km) counterclockwise orbit (as viewed from the Sun) and aimed its science instruments toward the 52-ft (16-m) wide site. The science observations from this pass are the closest taken of Osprey to date. In March, the spacecraft executed a similar pass over primary sample site Nightingale.

    A primary goal of the low flyover was to collect high-resolution imagery of the site’s surface material. The spacecraft’s sample collection mechanism is designed to pick up rocks smaller than 0.8 inches (2 cm), and the detailed PolyCam images from yesterday’s low pass will allow the team to identify rocks of this size.

    The flyover also provided the opportunity to capture images for the Natural Feature Tracking (NFT) image catalog for site Osprey – documenting the site’s surface features. If the mission decides to collect a sample from backup site Osprey, the spacecraft will use this NFT image catalog to autonomously navigate down to Bennu’s surface. The mission originally planned to collect this imagery during a 0.4-mile (620-m) flyover in February, but the images from that pass are out of focus due to an anomaly in the low energy laser transmitter (LELT) subsystem with the OSIRIS-REx Laser Altimeter (OLA), which was providing range measurements to focus PolyCam. OLA’s high energy laser transmitter (HELT) was used in this most recent Osprey flyover, as was done in a similar flyover of the Nightingale site.

    Several of the spacecraft’s other instruments also took observations of the Osprey site during the flyover event, including the OSIRIS-REx Thermal Emissions Spectrometer (OTES), the OSIRIS-REx Visual and InfraRed Spectrometer (OVIRS), and the OSIRIS-REx Laser Altimeter (OLA).

    After completing the pass, OSIRIS-REx returned to its safe-home orbit and is now circling Bennu clockwise. The spacecraft normally orbits Bennu counterclockwise, but this shift in orbital direction was necessary to position the spacecraft for its next close encounter with the asteroid – the second rehearsal for the sample collection event.

    The mission successfully executed the first sample-collection rehearsal on Apr. 14, completing a practice run of some of the activities leading up to the sampling event and bringing the spacecraft 213 ft (65 m) from the asteroid’s surface. The second rehearsal, scheduled for Aug. 11, will bring the spacecraft through the first three maneuvers of the sample collection sequence to an approximate altitude of 131 ft (40 m) over the surface of Bennu.

    The spacecraft will attempt to venture all the way to the asteroid’s surface on Oct. 20, for its first attempt to collect a sample from site Nightingale. During this event, OSIRIS-REx’s sampling mechanism will touch Bennu and fire a charge of pressurized nitrogen to disturb the surface and collect its sample before the spacecraft backs away.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  29. NASA’s OSIRIS-REx Ready for Touchdown on Asteroid Bennu

    May 20, 2020 -

    NASA’s first asteroid sample return mission is officially prepared for its long-awaited touchdown on asteroid Bennu’s surface. The Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer (OSIRIS-REx) mission has targeted Oct. 20 for its first sample collection attempt.

    This artist’s concept shows NASA’s OSIRIS-REx spacecraft descending towards asteroid Bennu to collect a sample of the asteroid’s surface. Credit: NASA/Goddard/University of Arizona

    “The OSIRIS-REx mission has been demonstrating the very essence of exploration by persevering through unexpected challenges,” said Thomas Zurbuchen, NASA’s associate administrator for science. “That spirit has led them to the cusp of the prize we all are waiting for – securing a sample of an asteroid to bring home to Earth, and I’m very excited to follow them through the home stretch.”

    From discovering Bennu’s surprisingly rugged and active surface, to entering the closest-ever orbit around a planetary body, OSIRIS-REx has overcome several challenges since arriving at the asteroid in December 2018. Last month, the mission brought the spacecraft 213 ft (65 m) from the asteroid’s surface during its first sample collection rehearsal — successfully completing a practice run of the activities leading up to the sampling event.

    Now that the mission is ready to collect a sample, the team is facing a different kind of challenge here on Earth. In response to COVID-19 constraints and after the intense preparation for the first rehearsal, the OSIRIS-REx mission has decided to provide its team with additional preparation time for both the final rehearsal and the sample collection event. Spacecraft activities require significant lead time for the development and testing of operations, and given the current requirements that limit in-person participation at the mission support area, the mission would benefit from giving the team additional time to complete these preparations in the new environment. As a result, both the second rehearsal and first sample collection attempt will have two extra months for planning.

    “In planning the mission, we included robust schedule margin while at Bennu to provide the flexibility to address unexpected challenges,” said Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center. “This flexibility has allowed us to adapt to the surprises that Bennu has thrown at us. It’s now time to prioritize the health and safety of both team members and the spacecraft.”

    The mission had originally planned to perform the first Touch-and-Go (TAG) sample collection event on Aug. 25 after completing a second rehearsal in June. This rehearsal, now scheduled for Aug. 11, will bring the spacecraft through the first three maneuvers of the sample collection sequence to an approximate altitude of 131 ft (40 m) over the surface of Bennu. The first sample collection attempt is now scheduled for Oct. 20, during which the spacecraft will descend to Bennu’s surface and collect material from sample site Nightingale.

    “This mission’s incredible performance so far is a testament to the extraordinary skill and dedication of the OSIRIS-REx team,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “I am confident that even in the face of the current challenge, this team will be successful in collecting our sample from Bennu.”

    During the TAG event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface for approximately five seconds, fire a charge of pressurized nitrogen to disturb the surface, and collect a sample before the spacecraft backs away. The mission has resources onboard for three sample collection opportunities. If the spacecraft successfully collects a sufficient sample on Oct. 20, no additional sampling attempts will be made. The spacecraft is scheduled to depart Bennu in mid-2021, and will return the sample to Earth on Sept. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  30. One Step Closer to Touching Asteroid Bennu

    April 15, 2020 -

    After the successful completion of its “Checkpoint” rehearsal, NASA’s first asteroid-sampling spacecraft is one step closer to touching down on asteroid Bennu. Yesterday, NASA’s OSIRIS-REx spacecraft performed the first practice run of its sample collection sequence, reaching an approximate altitude of 246 feet (75 meters) over site Nightingale before executing a back-away burn from the asteroid. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater in Bennu’s northern hemisphere.

    This artist’s concept shows the trajectory and configuration of NASA’s OSIRIS-REx spacecraft during Checkpoint rehearsal, which was the first time the mission practiced the initial steps of collecting a sample from asteroid Bennu. Credit: NASA/Goddard/University of Arizona

    The four-hour Checkpoint rehearsal took the spacecraft through the first two of the sampling sequence’s four maneuvers: the orbit departure burn and the Checkpoint burn. Checkpoint is so named because it is the location where the spacecraft autonomously checks its position and velocity before adjusting its trajectory down toward the location of the event’s third maneuver.

    Four hours after departing its 0.6-mile (1-km) safe-home orbit, the spacecraft performed the Checkpoint maneuver at an approximate altitude of 410 feet (125 meters) above Bennu’s surface. From there, the spacecraft continued to descend for another nine minutes on a trajectory toward – but not reaching – the location of the sampling event’s third maneuver, the “Matchpoint” burn. Upon reaching an altitude of approximately 246 ft (75 m) – the closest the spacecraft has ever been to Bennu – OSIRIS-REx performed a back-away burn to complete the rehearsal.

    During the rehearsal, the spacecraft successfully deployed its sampling arm, the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), from its folded, parked position out to the sample collection configuration. Additionally, some of the spacecraft’s instruments collected science and navigation images and made spectrometry observations of the sample site, as will occur during the sample collection event.

    This first rehearsal provided the mission team with practice navigating the spacecraft through both the orbit departure and Checkpoint maneuvers and with an opportunity to verify that the spacecraft’s imaging, navigation and ranging systems operated as expected during the first part of the descent sequence. Checkpoint rehearsal also gave the team confirmation that OSIRIS-REx’s Natural Feature Tracking (NFT) guidance system accurately estimated the spacecraft’s position and speed relative to Bennu as it descended toward the surface.

    The mission team has maximized remote work over the last month of preparations for the Checkpoint rehearsal, as part of the COVID-19 response. On the day of rehearsal, a limited number of personnel monitored the spacecraft’s telemetry from Lockheed Martin Space’s facility, NASA’s Goddard Space Flight Center and the University of Arizona, taking appropriate safety precautions, while the rest of the team performed their roles remotely.

    “This rehearsal let us verify flight system performance during the descent, particularly the autonomous update and execution of the Checkpoint burn,” said Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Executing this monumental milestone during this time of national crisis is a testament to the professionalism and focus of our team. It speaks volumes about their ‘can-do’ attitude and hopefully will serve as a bit of good news in these challenging times.”

    The spacecraft will travel all the way to the asteroid’s surface during its first sample collection attempt, scheduled for Aug. 25. During this event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface for approximately five seconds, fire a charge of pressurized nitrogen to disturb the surface and collect a sample before the spacecraft backs away. The spacecraft is scheduled to return the sample to Earth on Sept. 24, 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  31. Rehearsal Time for NASA’s Asteroid Sampling Spacecraft

    April 9, 2020 -

    In August, a robotic spacecraft will make NASA’s first-ever attempt to descend to the surface of an asteroid, collect a sample, and ultimately bring it safely back to Earth. In order to achieve this challenging feat, the OSIRIS-REx mission team devised new techniques to operate in asteroid Bennu’s microgravity environment – but they still need experience flying the spacecraft in close proximity to the asteroid in order to test them. So, before touching down at sample site Nightingale this summer, OSIRIS-REx will first rehearse the activities leading up to the event.

    This artist’s concept shows the trajectory and configuration of NASA’s OSIRIS-REx spacecraft during Checkpoint rehearsal, which is the first time the mission will practice the initial steps for collecting a sample from asteroid Bennu. Credit: NASA/Goddard/University of Arizona

    On Apr. 14, the mission will pursue its first practice run – officially known as “Checkpoint” rehearsal – which will also place the spacecraft the closest it’s ever been to Bennu. This rehearsal is a chance for the OSIRIS-REx team and spacecraft to test the first steps of the robotic sample collection event.

    During the full touchdown sequence, the spacecraft uses three separate thruster firings to make its way to the asteroid’s surface. After an orbit departure burn, the spacecraft executes the Checkpoint maneuver at 410 ft (125 m) above Bennu, which adjusts the spacecraft’s position and speed down toward the point of the third burn. This third maneuver, called “Matchpoint,” occurs at approximately 164 ft (50 m) from the asteroid’s surface and places the spacecraft on a trajectory that matches the rotation of Bennu as it further descends toward the targeted touchdown spot.

    The Checkpoint rehearsal allows the team to practice navigating the spacecraft through both the orbit departure and Checkpoint maneuvers, and ensures that the spacecraft’s imaging, navigation and ranging systems operate as expected during the first part of the descent sequence. Checkpoint rehearsal also gives the team a chance to confirm that OSIRIS-REx’s Natural Feature Tracking (NFT) guidance system accurately updates the spacecraft’s position and velocity relative to Bennu as it descends towards the surface.

    Checkpoint rehearsal, a four-hour event, begins with the spacecraft leaving its safe-home orbit, 0.6 miles (1 km) above the asteroid. The spacecraft then extends its robotic sampling arm – the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – from its folded, parked position out to the sample collection configuration. Immediately following, the spacecraft slews, or rotates, into position to begin collecting navigation images for NFT guidance. NFT allows the spacecraft to autonomously guide itself to Bennu’s surface by comparing an onboard image catalog with the real-time navigation images taken during descent. As the spacecraft descends to the surface, the NFT system updates the spacecraft’s predicted point of contact depending on OSIRIS-REx’s position in relation to Bennu’s landmarks.

    Before reaching the 410-ft (125-m) Checkpoint altitude, the spacecraft’s solar arrays move into a “Y-wing” configuration that safely positions them away from the asteroid’s surface. This configuration also places the spacecraft’s center of gravity directly over the TAGSAM collector head, which is the only part of the spacecraft that will contact Bennu’s surface during the sample collection event.

    In the midst of these activities, the spacecraft continues capturing images of Bennu’s surface for the NFT navigation system. The spacecraft will then perform the Checkpoint burn and descend toward Bennu’s surface for another nine minutes, placing the spacecraft around 243 ft (75 m) from the asteroid – the closest it has ever been.

    Upon reaching this targeted point, the spacecraft will execute a back-away burn, then return its solar arrays to their original position and reconfigure the TAGSAM arm back to the parked position. Once the mission team determines that the spacecraft successfully completed the entire rehearsal sequence, they will command the spacecraft to return to its safe-home orbit around Bennu.

    Following the Checkpoint rehearsal, the team will verify the flight system’s performance during the descent, and that the Checkpoint burn accurately adjusted the descent trajectory for the subsequent Matchpoint burn.

    The mission team has maximized remote work over the last month of preparations for the checkpoint rehearsal, as part of the COVID-19 response. On the day of rehearsal, a limited number of personnel will command the spacecraft from Lockheed Martin Space’s facility, taking appropriate safety precautions, while the rest of the team performs their roles remotely.

    The mission is scheduled to perform a second rehearsal on Jun. 23, taking the spacecraft through the Matchpoint burn and down to an approximate altitude of 82 ft (25 m). OSIRIS-REx’s first sample collection attempt is scheduled for Aug. 25.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  32. Bennu’s Boulders Shine as Beacons for NASA’s OSIRIS-REx

    March 9, 2020 -

    This summer, the OSIRIS-REx spacecraft will undertake NASA’s first-ever attempt to touch the surface of an asteroid, collect a sample of it, and safely back away. But since arriving at asteroid Bennu over a year ago, the mission team has been tackling an unexpected challenge: how to accomplish this feat at an asteroid whose surface is blanketed in building-sized boulders.

    During the sample collection event, Natural Feature Tracking (NFT) will guide NASA’s OSIRIS-REx spacecraft to asteroid Bennu’s surface. The spacecraft takes real-time images of the asteroid’s surface features as it descends, and then compares these images with an onboard image catalog. The spacecraft then uses these geographical markers to orient itself and accurately target the touchdown site. Credit: NASA/Goddard/University of Arizona

    Using these hazardous boulders as signposts, the mission team developed a new precision navigation method to overcome the challenge.

    The OSIRIS-REx team had originally planned to use a LIDAR system to navigate to Bennu’s surface during the Touch-And-Go (TAG) sample collection event. LIDAR is similar to radar, but it uses laser pulses rather than radio waves to measure distance. The OSIRIS-REx Guidance, Navigation, and Control (GNC) LIDAR is designed to navigate the spacecraft to a relatively hazard-free surface. The mission had originally envisioned a touchdown site 164 ft (50 meters) in diameter, but the largest safe areas on Bennu are much smaller. The biggest site is just 52 ft (16 m) wide, or roughly 10% of the safe area envisioned. The team realized that they needed a more precise navigation technique that would allow the spacecraft to accurately target very small sites while dodging potential hazards.

    In the face of this challenge, the OSIRIS-REx team switched to a new navigation method called Natural Feature Tracking (NFT). NFT provides more extensive navigation capabilities than LIDAR, and is key for executing what the team is calling “Bullseye TAG,” which delivers the spacecraft to the much smaller sampling area. As an optical navigation technique, it requires the creation of a high-resolution image catalog onboard the spacecraft.

    Earlier this year, the spacecraft made reconnaissance passes over the mission’s primary and backup sample collection sites, designated Nightingale and Osprey, flying as close as 0.4 miles (625 m) over the surface. During these flyovers, the spacecraft collected images from different angles and lighting conditions to complete the NFT image catalog. The team uses this catalog to identify boulders and craters unique to the sample site region, and will upload this information to the spacecraft before the sample collection event. NFT autonomously guides the spacecraft to Bennu’s surface by comparing the onboard image catalog with the real-time navigation images taken during descent. As the spacecraft descends to the surface, NFT updates its predicted point of contact depending on the spacecraft’s position in relation to the landmarks.

    On the ground, team members created “hazard maps” for both the Nightingale and Osprey sites to document all of the surface features that could potentially harm the spacecraft, like large rocks or steep slopes. The team used the image catalog in conjunction with data from the OSIRIS-REx Laser Altimeter (OLA) to create 3D maps that closely model Bennu’s topography. As part of NFT, these maps document boulder heights and crater depths, and guide the spacecraft away from potential hazards while targeting a very small site. During descent, if the spacecraft predicts it will touch unsafe terrain, it will autonomously wave-off and back away from the surface. However, if it sees that the area is free of hazards, it will continue to descend and attempt to collect a sample.

    During sample collection, Natural Feature Tracking (NFT) will guide NASA’s OSIRIS-REx spacecraft to asteroid Bennu’s surface. Hazard maps are also part of the NFT guidance system – they document boulder heights and crater depths, and guide the spacecraft away from potential hazards. Credit: NASA/Goddard/University of Arizona

    NFT will be used in April to navigate the spacecraft during its first sample collection rehearsal. The operations team performed preliminary testing during the Orbital B mission phase in late 2019, and the results demonstrated that NFT works in real-life conditions as designed. NFT will also be used for navigation during the second rehearsal planned for June.

    OSIRIS-REx’s first sample collection attempt is scheduled for late August. The spacecraft will depart Bennu in 2021 and is scheduled to deliver the sample to Earth in September 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  33. First Official Names Given to Features on Asteroid Bennu

    March 6, 2020 -

    Asteroid Bennu’s most prominent boulder, a rock chunk jutting out 71 ft (21.7 m) from the asteroid’s southern hemisphere, finally has a name. The boulder – which is so large that it was initially detected from Earth – is officially designated Benben Saxum after the primordial hill that first arose from the dark waters in an ancient Egyptian creation myth.

    This flat projection mosaic of asteroid Bennu shows the locations of the first 12 surface features to receive official names from the International Astronomical Union. The accepted names were proposed by NASA’s OSIRIS-REx team members, who have been mapping the asteroid in detail over the last year. Bennu’s surface features are named after birds and bird-like creatures in mythology, and the places associated with them. Credit: NASA/Goddard/University of Arizona

    Benben Saxum and 11 other features on the asteroid are the first to receive official Bennu feature names approved by the International Astronomical Union (IAU), the internationally recognized authority for naming celestial bodies and their surface features. The accepted names were proposed by NASA’s OSIRIS-REx team members, who have been mapping the asteroid in detail over the last year. The OSIRIS-REx spacecraft, NASA’s first asteroid sample return mission, is currently visiting the asteroid and is scheduled to collect a sample from Bennu’s surface this summer.

    “Since arriving at the asteroid, the OSIRIS-REx team has become incredibly familiar with all of the geological features on Bennu,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “These features are providing us with insight into Bennu’s history, and their new names symbolize the essence of the mission – studying the past to both discover our origins and understand our future,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson.

    The approved Bennu surface feature names are listed below. Bennu’s diverse terrain types – including regiones (broad geographic regions), craters, dorsa (ridges), fossae (grooves or trenches) and saxa (rocks and boulders) – will be named after birds and bird-like creatures in mythology, and the places associated with them.

     

    Credit: NASA/Goddard/University of Arizona

    Tlanuwa Regio is named for the giant birds who scattered the Earth with pieces of a serpent that turned into standing pillars of rocks in Cherokee mythology. Tlanuwa Regio is an area covered by large boulders in Bennu’s southern hemisphere.

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Benben Saxum is named for an ancient Egyptian mound that arose from the primordial waters Nu. In Egyptian mythology, the god Atum settled upon Benben to create the world after his flight over the waters in the form of the Bennu bird. Benben Saxum is the tallest boulder on Bennu.

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Roc Saxum is named for the Roc, an enormous bird of prey in Arabian mythology of the Middle East. Roc Saxum is the largest boulder feature on Bennu.

     

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Simurgh Saxum is named for the benevolent, mythological bird in Persian mythology. The Simurgh was said to possess all knowledge, and Simurgh Saxum defines the prime meridian on Bennu and is the basis for the asteroid’s coordinate system.

     

     

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Huginn Saxum and Muninn Saxum are adjacent boulders named for the two ravens, Huginn and Muninn, who accompany the god Odin in Norse mythology.

     

     

     

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Ocypete Saxum is named for one of the Greek harpies, the half-maiden and half-bird personification of storm winds that would snatch and carry things away from Earth. Ocypete Saxum is located near the origin of the Jan. 19, 2019, particle ejection event on Bennu.

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Strix Saxum is named for the Strix bird of ill-omen from Roman mythology. Strix Saxum is a large boulder flanking the OSIRIS-REx mission’s backup sample collection site.

     

     

     

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Amihan Saxum is named for the Tagalog (Philippines) mythological deity, who is depicted as a bird and was the first creature to inhabit the universe. This large, flat boulder appears to be partly buried and is located in Tlanuwa Regio, which has an unusually high concentration of large boulders.

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Pouakai Saxum is named for the monstrous bird who kills and eat humans in Māori (Polynesia) mythology. Pouakai Saxum is a 55 ft (10.6 m)-wide boulder located in Bennu’s southern hemisphere, slightly north of Benben Saxum.

     

     

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Aetos Saxum is named for the childhood playmate of the supreme god Zeus, who was turned into an eagle by Hera in Greek mythology. Aetos Saxum is a conspicuously flat boulder, with a general wing-like shape located near Bennu’s equator.

     

     

     

     

     

     

     

     

    Credit: NASA/Goddard/University of Arizona

    Gargoyle Saxum is named for the French dragon-like monster with wings, bird-like neck, and the ability to breathe fire. Gargoyle Saxum is a large prominent boulder near the mission’s backup sample site that is one of the darkest objects on the surface.

     

     

     

     

     

     

     

     

     

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  34. OSIRIS-REx Swoops Over Sample Site Nightingale

    March 4, 2020 -

    NASA’s first asteroid-sampling spacecraft just got its best look yet at asteroid Bennu. Yesterday, the OSIRIS-REx spacecraft executed a very low pass over sample site Nightingale, taking observations from an altitude of 820 feet (250 m), which is the closest that OSIRIS-REx has flown over the asteroid so far. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater in Bennu’s northern hemisphere.

    On Mar. 3, the OSIRIS-REx spacecraft performed a low-altitude flyover of site Nightingale. During the pass, science observations of asteroid Bennu took place from a distance of approximately 820 ft (250 m) – the closest the spacecraft has ever been to the asteroid’s surface. Credit: University of Arizona

    To perform the 5-hour flyover, the spacecraft left its 0.6-mile (1-km) safe-home orbit and aimed its science instruments toward the 52-ft (16-m) wide sample site. The science observations from this pass are the closest taken of Bennu to date.

    The main goal of yesterday’s low flyover was to collect high-resolution imagery of the site’s surface material. The spacecraft’s sample collection mechanism is designed to pick up small rocks less than 0.8 inches (2 cm) in size, and the PolyCam images from this low pass are very detailed, allowing the team to identify and locate rocks of this size. Several of the spacecraft’s other instruments also took observations of the Nightingale site during the flyover event, including the OSIRIS-REx Thermal Emissions Spectrometer (OTES), the OSIRIS-REx Visual and InfraRed Spectrometer (OVIRS), the OSIRIS-REx Laser Altimeter (OLA), and the MapCam color imager.

    After completing the flyover, the spacecraft returned to orbit – but for the first time, OSIRIS-REx reversed the direction of its safe-home orbit and is now circling Bennu clockwise (as viewed from the Sun). This shift in orbital direction positioned the spacecraft for its next close encounter with the asteroid – its first rehearsal for the sample collection event.

    This spring, the mission will perform two rehearsals in preparation for the sample collection event. The first rehearsal, scheduled for Apr. 14, navigates the spacecraft down to 410 feet (125 m) over Bennu’s surface. At this altitude, the spacecraft will execute the Checkpoint maneuver, designed to put the spacecraft on a descent trajectory toward the sample collection site on the surface. The spacecraft will stop its descent ten minutes later at an altitude of approximately 164 ft (50 m) by executing a maneuver to back away from the asteroid. The second rehearsal, scheduled for June, follows the same trajectory but takes the spacecraft to a lower altitude of 164 feet (50 m), where it will perform the Matchpoint maneuver, designed to slow the spacecraft’s descent rate. Subsequent to this burn the spacecraft will execute a back away maneuver between 131 ft (40 m) and 82 ft (25 m) from Bennu’s surface. The spacecraft will venture all the way to the asteroid’s surface in late August, for its first attempt to collect a sample. During this event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface and fire a charge of pressurized nitrogen to disturb the surface and collect its sample before the spacecraft backs away.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  35. NASA’s OSIRIS-REx Students Catch Unexpected Glimpse of Newly Discovered Black Hole

    February 28, 2020 -

    University students and researchers working on a NASA mission orbiting a near-Earth asteroid have made an unexpected detection of a phenomenon 30 thousand light years away. Last fall, the student-built Regolith X-Ray Imaging Spectrometer (REXIS) onboard NASA’s OSIRIS-REx spacecraft detected a newly flaring black hole in the constellation Columba while making observations off the limb of asteroid Bennu.

    This visualization simulates an X-ray outburst from the black hole MAXI J0637-043, detected by the REXIS instrument on NASA’s OSIRIS-REx spacecraft, as it moves through REXIS’s line of sight. At first, the outburst is visibly intense, but it gradually fades as it subsides. The animation was constructed using data collected by the X-ray spectrometer while REXIS was making observations of the space around asteroid Bennu on Nov. 11, 2019. Credit: NASA/Goddard/University of Arizona/MIT/Harvard

    REXIS, a shoebox-sized student instrument, was designed to measure the X-rays that Bennu emits in response to incoming solar radiation. X-rays are a form of electromagnetic radiation, like visible light, but with much higher energy. REXIS is a collaborative experiment led by students and researchers at MIT and Harvard, who proposed, built, and operate the instrument.

    On Nov. 11, 2019, while the REXIS instrument was performing detailed science observations of Bennu, it captured X-rays radiating from a point off the asteroid’s edge. “Our initial checks showed no previously cataloged object in that position in space,” said Branden Allen, a Harvard research scientist and student supervisor who first spotted the source in the REXIS data.

    The glowing object turned out to be a newly flaring black hole X-ray binary – discovered just a week earlier by Japan’s MAXI telescope – designated MAXI J0637-430. NASA’s Neutron Star Interior Composition Explorer (NICER) telescope also identified the X-ray blast a few days later. Both MAXI and NICER operate aboard NASA’s International Space Station and detected the X-ray event from low Earth orbit. REXIS, on the other hand, detected the same activity millions of miles from Earth while orbiting Bennu, the first such outburst ever detected from interplanetary space.

    “Detecting this X-ray burst is a proud moment for the REXIS team. It means our instrument is performing as expected and to the level required of NASA science instruments,” said Madeline Lambert, an MIT graduate student who designed the instrument’s command sequences that serendipitously revealed the black hole.

    X-ray blasts, like the one emitted from the newly discovered black hole, can only be observed from space since Earth’s protective atmosphere shields our planet from X-rays. These X-ray emissions occur when a black hole pulls in matter from a normal star that is in orbit around it. As the matter spirals onto a spinning disk surrounding the black hole, an enormous amount of energy (primarily in the form of X-rays) is released in the process.

    This image shows the X-ray outburst from the black hole MAXI J0637-043, detected by the REXIS instrument on NASA’s OSIRIS-REx spacecraft. The image was constructed using data collected by the X-ray spectrometer while REXIS was making observations of the space around asteroid Bennu on Nov. 11, 2019. The outburst is visible in the center of the image, and the image is overlaid with the limb of Bennu (lower right) to illustrate REXIS’s field of view. Credit: NASA/Goddard/University of Arizona/MIT/Harvard

    “We set out to train students how to build and operate space instruments,” said MIT professor Richard Binzel, instrument scientist for the REXIS student experiment. “It turns out, the greatest lesson is to always be open to discovering the unexpected.”

    The main purpose of the REXIS instrument is to prepare the next generation of scientists, engineers, and project managers in the development and operations of spaceflight hardware. Nearly 100 undergraduate and graduate students have worked on the REXIS team since the mission’s inception.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  36. Status Update: OSIRIS-REx Osprey Flyover

    February 13, 2020 -

    On Feb. 11, NASA’s OSIRIS-REx spacecraft safely executed a 0.4-mile (620-m) flyover of the backup sample collection site Osprey as part of the mission’s Reconnaissance B phase activities. Preliminary telemetry, however, indicates that the OSIRIS-REx Laser Altimeter (OLA) did not operate as expected during the 11-hour event. The OLA instrument was scheduled to provide ranging data to the spacecraft’s PolyCam imager, which would allow the camera to focus while imaging the area around the sample collection site. Consequently, the PolyCam images from the flyover are likely out of focus.

    The other science instruments, including the MapCam imager, the OSIRIS-REx Thermal Emissions Spectrometer (OTES), and the OSIRIS-REx Visual and InfraRed Spectrometer (OVIRS), all performed nominally during the flyover. These instruments and the spacecraft continue in normal operations in orbit around asteroid Bennu.

    The mission team is currently reviewing the available data from the flyover in order to fully assess the OLA instrument. The entire data set from the flyover, including the PolyCam images, will be completely downlinked from the spacecraft next week and will provide additional insight into any impact that the loss of the OLA data may have.

    OLA has already completed all of its principal requirements for the OSIRIS-REx mission. OLA’s scans of Bennu’s surface were used to create the high-resolution 3D global maps of Bennu’s topography that were crucial for selecting the primary and backup sample collection sites last fall.

  37. OSIRIS-REx Completes Closest Flyover of Sample Site Nightingale

    January 22, 2020 -

    Preliminary results indicate that NASA’s OSIRIS-REx spacecraft successfully executed a 0.4-mile (620-m) flyover of site Nightingale yesterday as part of the mission’s Reconnaissance B phase activities. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater high in asteroid Bennu’s northern hemisphere.

    During the Recon B flyover of primary sample collection site Nightingale, OSIRIS-REx left its safe-home orbit to fly over the sample site at an altitude of 0.4 miles (620 m). The pass, which took around 11 hours, gave the spacecraft’s onboard instruments the opportunity to take the closest-ever science observations of the site. Credit: NASA/Goddard/University of Arizona

    To perform the pass, the spacecraft left its 0.75-mile (1.2-km) safe home orbit and flew an almost 11-hour transit over the asteroid, aiming its science instruments toward the 52-ft (16-m) wide sample site before returning to orbit. Science observations from this flyover are the closest taken of a sample site to date.

    The primary goal of the Nightingale flyover was to collect the high-resolution imagery required to complete the spacecraft’s Natural Feature Tracking image catalog, which will document the sample collection site’s surface features – such as boulders and craters. During the sampling event, which is scheduled for late August, the spacecraft will use this catalog to navigate with respect to Bennu’s surface features, allowing it to autonomously predict where on the sample site it will make contact . Several of the spacecraft’s other instruments also took observations of the Nightingale site during the flyover event, including the OSIRIS-REx Thermal Emissions Spectrometer (OTES), the OSIRIS-REx Visual and InfraRed Spectrometer (OVIRS), the OSIRIS-REx Laser Altimeter (OLA), and the MapCam color imager.

    A similar flyover of the backup sample collection site, Osprey, is scheduled for Feb. 11. Even lower flybys will be performed later this spring – Mar. 3 for Nightingale and May 26 for Osprey – as part of the mission’s Reconnaissance C phase activities. The spacecraft will perform these two flyovers at an altitude of 820 feet (250 m), which will be the closest it has ever flown over asteroid Bennu’s surface.

  38. X Marks the Spot: NASA Selects Site for Asteroid Sample Collection

    December 12, 2019 -

    After a year scoping out asteroid Bennu’s boulder-scattered surface, the team leading NASA’s first asteroid sample return mission has officially selected a sample collection site.

    This image shows sample site Nightingale, OSIRIS-REx’s primary sample collection site on asteroid Bennu. The image is overlaid with a graphic of the OSIRIS-REx spacecraft to illustrate the scale of the site. Credit: NASA/Goddard/University of Arizona

    The Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-Rex) mission team concluded a site designated “Nightingale” – located in a crater high in Bennu’s northern hemisphere – is the best spot for the OSIRIS-REx spacecraft to snag its sample.

    The OSIRIS-REx team spent the past several months evaluating close-range data from four candidate sites in order to identify the best option for the sample collection. The candidate sites – dubbed Sandpiper, Osprey, Kingfisher, and Nightingale – were chosen for investigation because, of all the potential sampling regions on Bennu, these areas pose the fewest hazards to the spacecraft’s safety while still providing the opportunity for great samples to be gathered.

    “After thoroughly evaluating all four candidate sites, we made our final decision based on which site has the greatest amount of fine-grained material and how easily the spacecraft can access that material while keeping the spacecraft safe,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. “Of the four candidates, site Nightingale best meets these criteria and, ultimately, best ensures mission success.”

    Site Nightingale is located in a northern crater 460 ft (140 m) wide. Nightingale’s regolith – or rocky surface material – is dark, and images show that the crater is relatively smooth. Because it is located so far north, temperatures in the region are lower than elsewhere on the asteroid and the surface material is well-preserved. The crater also is thought to be relatively young, and the regolith is freshly exposed. This means the site would likely allow for a pristine sample of the asteroid, giving the team insight into Bennu’s history.

    Although Nightingale ranks the highest of any location on Bennu, the site still poses challenges for sample collection. The original mission plan envisioned a sample site with a diameter of 164 feet (50 m). While the crater that hosts Nightingale is larger than that, the area safe enough for the spacecraft to touch is much smaller – approximately 52 ft (16 m) in diameter, resulting in a site that is only about one-tenth the size of what was originally envisioned This means the spacecraft has to very accurately target Bennu’s surface. Nightingale also has a building-size boulder situated on the crater’s eastern rim, which could pose a hazard to the spacecraft while backing away after contacting the site.

    This image shows sample site Osprey, OSIRIS-REx’s backup sample collection site on asteroid Bennu. The image is overlaid with a graphic of the OSIRIS-REx spacecraft to illustrate the scale of the site. Credit:

    The mission also selected site Osprey as a backup sample collection site. The spacecraft has the capability to perform multiple sampling attempts, but any significant disturbance to Nightingale’s surface would make it difficult to collect a sample from that area on a later attempt, making a backup site necessary. The spacecraft is designed to autonomously “wave-off” from the site if its predicted position is too close to a hazardous area. During this maneuver, the exhaust plumes from the spacecraft’s thrusters could potentially disturb the surface of the site, due to the asteroid’s microgravity environment. In any situation where a follow-on attempt at Nightingale is not possible, the team will try to collect a sample from site Osprey instead.

    “Bennu has challenged OSIRIS-REx with extraordinarily rugged terrain,” said Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center. “The team has adapted by employing a more accurate, though more complex, optical navigation technique to be able to get into these small areas. We’ll also arm OSIRIS-REx with the capability to recognize if it is on course to touch a hazard within or adjacent to the site and wave-off before that happens.”

    With the selection of final primary and backup sites, the mission team will undertake further reconnaissance flights over Nightingale and Osprey, beginning in January and continuing through the spring. Once these flyovers are complete, the spacecraft will begin rehearsals for its “touch-and-go” sample collection event, which is scheduled for August. The spacecraft will depart Bennu in 2021 and is scheduled to return to Earth in September 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

    This flat projection mosaic of asteroid Bennu shows the relative locations of the primary and backup sample collection sites on the asteroid: Nightingale and Osprey. NASA’s OSIRIS-REx spacecraft is scheduled to collect a sample in summer 2020. Credit: NASA/Goddard/University of Arizona

     

  39. NASA’s OSIRIS-REx Mission Explains Bennu’s Mysterious Particle Events

    December 4, 2019 -

    Shortly after NASA’s OSIRIS-REx spacecraft arrived at asteroid Bennu, an unexpected discovery by the mission’s science team revealed that the asteroid could be active, or consistently discharging particles into space. The ongoing examination of Bennu – and its sample that will eventually be returned to Earth – could potentially shed light on why this intriguing phenomenon is occurring.

    This view of asteroid Bennu ejecting particles from its surface on January 6 was created by combining two images taken by the NavCam 1 imager onboard NASA’s OSIRIS-REx spacecraft: a short exposure image (1.4 ms), which shows the asteroid clearly, and a long exposure image (5 sec), which shows the particles clearly. Credit: NASA/Goddard/University of Arizona/Lockheed Martin

    The OSIRIS-REx team first observed a particle ejection event in images captured by the spacecraft’s navigation cameras taken on Jan. 6, just a week after the spacecraft entered its first orbit around Bennu. At first glance, the particles appeared to be stars behind the asteroid, but on closer examination, the team realized that the asteroid was ejecting material from its surface. After concluding that these particles did not compromise the spacecraft’s safety, the mission began dedicated observations in order to fully document the activity.

    “Among Bennu’s many surprises, the particle ejections sparked our curiosity, and we’ve spent the last several months investigating this mystery,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “This is a great opportunity to expand our knowledge of how asteroids behave.”

    After studying the results of the observations, the mission team released their findings in a Science paper published Dec. 6. The team observed the three largest particle ejection events on Jan. 6 and 19, and Feb. 11, and concluded that the events originated from different locations on Bennu’s surface. The first event originated in the southern hemisphere, and the second and third events occurred near the equator. All three events took place in the late afternoon on Bennu.

    The team found that, after ejection from the asteroid’s surface, the particles either briefly orbited Bennu and fell back to its surface or escaped from Bennu into space. The observed particles traveled up to 10 feet (3 meters) per second, and measured from smaller than an inch up to 4 inches (10 cm) in size. Approximately 200 particles were observed during the largest event, which took place on Jan. 6.

    The team investigated a wide variety of possible mechanisms that may have caused the ejection events, and narrowed the list to three candidates: meteoroid impacts, thermal stress fracturing, and released of water vapor.

    Meteoroid impacts are common in the deep space neighborhood of Bennu, and it is possible that these small fragments of space rock could be hitting Bennu where OSIRIS-REx is not observing it, shaking loose particles with the momentum of their impact.

    The team also determined that thermal fracturing is another reasonable explanation. Bennu’s surface temperatures vary drastically over its 4.3-hour rotation period.

    This animation illustrates the modeled trajectories of particles that were ejected from Bennu’s surface on January 19. After ejecting from the asteroid’s surface, the particles either briefly orbited Bennu and fell back to its surface or escaped away from Bennu and into space. Credit: NASA/Goddard/University of Arizona/Lauretta & Hergenrother et al., Science 10.1126

    Although it is extremely cold during the night hours, the asteroid’s surface warms significantly in the mid-afternoon, which is when the three major events occurred. As a result of this temperature change, rocks may begin to crack and break down, and eventually particles could be ejected from the surface. This cycle is known as thermal stress fracturing.

    Water release may also explain the asteroid’s activity. When Bennu’s water-locked clays are heated, the water could begin to release and create pressure. It is possible that as pressure builds in cracks and pores in boulders where absorbed water is released, the surface could become agitated, causing particles to erupt.

    But nature does not always allow for simple explanations. “It could be that more than one of these possible mechanisms are at play,” said Steve Chesley, an author on the paper and Senior Research Scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “For example, thermal fracturing could be chopping the surface material into small pieces, making it far easier for meteoroid impacts to launch pebbles into space.”

    If thermal fracturing, meteoroid impacts, or both, are in fact the causes of these ejection events, then this phenomenon is likely happening on all small asteroids, as they all experience these mechanisms. However, if water release is the cause of these ejection events, then this phenomenon would be specific to asteroids that contain water-bearing minerals, like Bennu.

    Bennu’s activity presents larger opportunities once a sample is collected and returned to Earth for study. Many of the ejected particles are small enough to be collected by the spacecraft’s sampling mechanism, meaning that the returned sample may possibly contain some material that was ejected and returned to Bennu’s surface. Determining that a particular particle had been ejected and returned to Bennu might be a scientific feat similar to finding a needle in a haystack. The material returned to Earth from Bennu, however, will almost certainly increase our understanding of asteroids and the ways they are both different and similar, even as the particle ejection phenomenon continues to be a mystery whose clues we’ll also return home with in the form of data and further material for study.

    Sample collection is scheduled for summer 2020, and the sample will be delivered to Earth in September 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  40. NASA’s OSIRIS-REx in the Midst of Site Selection

    By Brittany Enos

    December 4, 2019 -

    NASA’s OSIRIS-REx mission is just days away from selecting the site where the spacecraft will snag a sample from asteroid Bennu. After a lengthy and challenging process, the team is finally ready to down-select from the four candidate sites to a primary and backup site.

    OSIRIS-REx is NASA’s first asteroid sample return mission, so this decision of a sample collection site is key for asteroid operations and mission success.

    After selecting the four candidate sample sites – Sandpiper, Osprey, Kingfisher, and Nightingale – in July, the mission completed its Reconnaissance A phase. During Recon A, the OSIRIS-REx spacecraft performed a month-long series of four flyovers – one over each potential sample collection site. This mission phase provided the team with high-resolution imagery in order to thoroughly examine the sampleability (fine-grained material), topography, albedo, and color of each site. The data collected from these high-altitude flyovers is central for determining which site is best-suited for sample collection.

    These are images of the four candidate sample collection sites on asteroid Bennu: Nightingale, Kingfisher, Osprey and Sandpiper. One of these four sites will ultimately be the location on which NASA’s OSIRIS-REx spacecraft will touch down to collect a sample. Credit: NASA/Goddard/University of Arizona

    While the mission is one step closer to collecting a sample, Recon A observations have revealed that even the best candidate sites on Bennu pose significant challenges to sample collection, and the choice before the site selection board is not an easy one.

    “Sample site selection really is a comprehensive activity. It requires that we look at many different types of data in many different ways to ensure the selected site is the best choice in terms of spacecraft safety, presence of sampleable material, and science value,” said Heather Enos, OSIRIS-REx deputy principal investigator at the University of Arizona, Tucson, and chair of the sample site selection board. “Our team is incredibly innovative and integrated, which is what makes the selection process work.”

    The most recent images show that while there is fine-grained material (smaller than 2.5 cm in diameter), much of it may not be easily accessible. The mission was originally designed for a beach-like surface, with “ponds” of sandy material, not for Bennu’s rugged terrain. In reality the potential sample sites are not large, clear areas, but rather small spaces surrounded by large boulders, so navigating the spacecraft in and out of the sites will require a bit more fine-tuning than originally planned.

    Starting in Bennu’s southern hemisphere, site Sandpiper was the first flyover of the Recon A mission phase. Sandpiper is one of the “safer” sites because it is located in a relatively flat area, making it easier for the spacecraft to navigate in and out. The most recent images show that fine-grained material is present, but the sandy regolith is trapped between larger rocks, which makes it difficult for the sampling mechanism to operate.

    Site Osprey was the second site observed during Recon A. This site was originally chosen based on its strong spectral signature of carbon-rich material and because of a dark patch in the center of the crater, which was thought to possibly be fine-grained material. However, the latest high-resolution imagery of Osprey suggests that the site is scattered with material that may be too large to ingest for the sampling mechanism.

    Site Kingfisher was selected because it is located in a small crater – meaning that it may be a relatively young feature compared to Bennu’s larger craters (such as the one in which Sandpiper is located). Younger craters generally hold fresher, minimally-altered material. High-resolution imagery captured during the Recon A flyover revealed that while the original crater may be too rocky, a neighboring crater appears to contain fine-grained material.

    Recon A concluded with a flyover of site Nightingale. Images show that the crater holds a good amount of unobstructed fine-grained material. However, while the sampleability of the site ranks high, Nightingale is located far to the north where the lighting conditions create additional challenges for spacecraft navigation. There is also a building-size boulder situated on the crater’s eastern rim, which could be a hazard to the spacecraft when backing away after contacting the site.

    Bennu has also made it a challenge for the mission to identify a site that won’t trigger the spacecraft’s safety mechanisms. During Recon A, the team began cataloguing Bennu’s surface features to create maps for the Natural Feature Tracking (NFT) autonomous navigation system. During the sample collection event, the spacecraft will use NFT to navigate to the asteroid’s surface by comparing the onboard image catalog to the navigation images it will take during descent. In response to Bennu’s extremely rocky surface, the NFT system has been augmented with a new safety feature, which instructs it to wave-off the sampling attempt and back away if it determines the point of contact is near a potentially hazardous surface feature. With Bennu’s building-sized boulders and small target sites, the team realizes that there is a possibility that the spacecraft will wave-off the first time it descends to collect a sample.

    This flat projection mosaic of asteroid Bennu shows the relative locations of the four candidate sample collection sites on the asteroid: Nightingale, Kingfisher, Osprey and Sandpiper. NASA’s OSIRIS-REx spacecraft is scheduled to touch down on one of these four sites to collect a sample in summer 2020. Credit: NASA/Goddard/University of Arizona

    “Bennu’s challenges are an inherent part of this mission, and the OSIRIS-REx team has responded by developing robust measures to overcome them,” said Mike Moreau, OSIRIS-REx deputy project manager at Goddard. “If the spacecraft executes a wave-off while attempting to collect a sample, that simply means that both the team and the spacecraft have done their jobs to ensure the spacecraft can fly another day. The success of the mission is our first priority.”

    Whichever site wins the race, the OSIRIS-REx mission team is ready for whatever new challenges Bennu may bring. Next spring, the team will undertake further reconnaissance flights over the primary and backup sample sites, and will then start spacecraft rehearsals for touchdown. Sample collection is scheduled for summer 2020, and the sample will return to Earth in September 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  41. Flyover of the Candidate Sample Sites

    August 29, 2019 -

    This animated flyover of each of the four candidate sample collection sites on asteroid Bennu, selected by NASA’s OSIRIS-REx asteroid sample return mission, was produced using close-range data from the OSIRIS-REx Laser Altimeter (OLA), an instrument contributed by the Canadian Space Agency. It illustrates the location of each site on Bennu, the topography of each site, and the potential sampling regions that the spacecraft will target, which are 10 meters in diameter.

    The laser altimeter on NASA’s OSIRIS-REx spacecraft has produced the highest resolution topographic maps ever of any planetary body. These maps of asteroid Bennu provide three-dimensional, detailed views of the OSIRIS-REx mission’s final four candidate sample collection sites, which are designated Nightingale, Kingfisher, Osprey and Sandpiper.

    OLAis equipped with two lasers and uses a steerable mirror to rapidly scan the asteroid’s surface to produce detailed images of boulders, craters and other geological features. OLA collected scans using its low-energy laser transmitter (LELT) during the spacecraft’s low altitude orbit– approximately 700 meters above Bennu’s surface. The LELT is designed to fire 10,000 light pulses per second at the asteroid, and three-dimensional terrain models of the four sites were produced using these light pulses.

    High-resolution maps of the four potential sample sites will allow the OSIRIS-REx team to assess the safety and accessibility of each region, locate landmarks that will help the spacecraft navigate during sample collection and identify areas of fine-grained material compatible with OSIRIS-REx’s sampling mechanism. These maps will be crucial for selecting the final two sample collection sites in December.

    OLA’s LELT will continue to gather Bennu data in tandem with the other instruments on the OSIRIS-REx spacecraft. The final selection of a primary and backup sample collection site will be announced in December 2019, and sample collection is scheduled for the latter half of 2020.

    Credit: NASA/Goddard/University of Arizona/CSA/York University/MDA

  42. NASA Mission Selects Final Four Site Candidates for Asteroid Sample Return

    August 12, 2019 -

    After months grappling with the rugged reality of asteroid Bennu’s surface, the team leading NASA’s first asteroid sample return mission has selected four potential sites for the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft to “tag” its cosmic dance partner.

    Since its arrival in December 2018, the OSIRIS-REx spacecraft has mapped the entire asteroid in order to identify the safest and most accessible spots for the spacecraft to collect a sample. These four sites now will be studied in further detail in order to select the final two sites – a primary and backup – in December.

    The final four candidate sample collection sites on asteroid Bennu are designated Nightingale, Kingfisher, Osprey and Sandpiper. The final site will be selected in December 2019. Credit: NASA/Goddard/University of Arizona/CSA/York/MDA

    The team originally had planned to choose the final two sites by this point in the mission. Initial analysis of Earth-based observations suggested the asteroid’s surface likely contains large “ponds” of fine-grain material. The spacecraft’s earliest images, however, revealed Bennu has an especially rocky terrain. Since then, the asteroid’s boulder-filled topography has created a challenge for the team to identify safe areas containing sampleable material, which must be fine enough – less than 1 inch (2.5 cm) in diameter – for the spacecraft’s sampling mechanism to ingest it.

    “We knew that Bennu would surprise us, so we came prepared for whatever we might find,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “As with any mission of exploration, dealing with the unknown requires flexibility, resources and ingenuity. The OSIRIS-REx team has demonstrated these essential traits for overcoming the unexpected throughout the Bennu encounter.”

    The original mission schedule intentionally included more than 300 days of extra time during asteroid operations to address such unexpected challenges. In a demonstration of its flexibility and ingenuity in response to Bennu’s surprises, the mission team is adapting its site selection process. Instead of down-selecting to the final two sites this summer, the mission will spend an additional four months studying the four candidate sites in detail, with a particular focus on identifying regions of fine-grain, sampleable material from upcoming, high-resolution observations of each site. The boulder maps that citizen science counters helped create through observations earlier this year were used as one of many pieces of data considered when assessing each site’s safety. The data collected will be key to selecting the final two sites best suited for sample collection.

    In order to further adapt to Bennu’s ruggedness, the OSIRIS-REx team has made other adjustments to its sample site identification process. The original mission plan envisioned a sample site with a radius of 82 feet (25 m). Boulder-free sites of that size don’t exist on Bennu, so the team has instead identified sites ranging from 16 to 33 feet (5 to 10 m) in radius. In order for the spacecraft to accurately target a smaller site, the team reassessed the spacecraft’s operational capabilities to maximize its performance. The mission also has tightened its navigation requirements to guide the spacecraft to the asteroid’s surface, and developed a new sampling technique called “Bullseye TAG,” which uses images of the asteroid surface to navigate the spacecraft all the way to the actual surface with high accuracy. The mission’s performance so far has demonstrated the new standards are within its capabilities.

    “Although OSIRIS-REx was designed to collect a sample from an asteroid with a beach-like area, the extraordinary in-flight performance to date demonstrates that we will be able to meet the challenge that the rugged surface of Bennu presents,” said Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That extraordinary performance encompasses not only the spacecraft and instruments, but also the team who continues to meet every challenge that Bennu throws at us.”

    The four candidate sample sites on Bennu are designated Nightingale, Kingfisher, Osprey, and Sandpiper – all birds native to Egypt. The naming theme complements the mission’s two other naming conventions – Egyptian deities (the asteroid and spacecraft) and mythological birds (surface features on Bennu).

    The final four candidate sample collection sites on asteroid Bennu are designated Nightingale, Kingfisher, Osprey and Sandpiper. Each circle has a 16.4 ft (5 m) radius. Credit: NASA/Goddard/University of Arizona

    The four sites are diverse in both geographic location and geological features. While the amount of sampleable material in each site has yet to be determined, all four sites have been evaluated thoroughly to ensure the spacecraft’s safety as it descends to, touches and collects a sample from the asteroid’s surface.

    Nightingale is the northern-most site, situated at 56 degrees north latitude on Bennu. There are multiple possible sampling regions in this site, which is set in a small crater encompassed by a larger crater 459 feet (140 m) in diameter. The site contains mostly fine-grain, dark material and has the lowest albedo, or reflection, and surface temperature of the four sites.

    Kingfisher is located in a small crater near Bennu’s equator at 11 degrees north latitude. The crater has a diameter of 26 feet (8 m) and is surrounded by boulders, although the site itself is free of large rocks. Among the four sites, Kingfisher has the strongest spectral signature for hydrated minerals.

    Osprey is set in a small crater, 66 feet (20 m) in diameter, which is also located in Bennu’s equatorial region at 11 degrees north latitude. There are several possible sampling regions within the site. The diversity of rock types in the surrounding area suggests that the regolith within Osprey may also be diverse. Osprey has the strongest spectral signature of carbon-rich material among the four sites.

    Sandpiper is located in Bennu’s southern hemisphere, at 47 degrees south latitude. The site is in a relatively flat area on the wall of a large crater 207 ft (63 m) in diameter. Hydrated minerals are also present, which indicates that Sandpiper may contain unmodified water-rich material.

    This fall, OSIRIS-REx will begin detailed analyses of the four candidate sites during the mission’s reconnaissance phase. During the first stage of this phase, the spacecraft will execute high passes over each of the four sites from a distance of 0.8 miles (1.29 km) to confirm they are safe and contain sampleable material. Closeup imaging also will map the features and landmarks required for the spacecraft’s autonomous navigation to the asteroid’s surface. The team will use the data from these passes to select the final primary and backup sample collection sites in December.

    The final four candidate sample collection sites shown on a map of asteroid Bennu. They are designated Nightingale, Kingfisher, Osprey and Sandpiper. Credit: NASA/Goddard/University of Arizona

    The second and third stages of reconnaissance will begin in early 2020 when the spacecraft will perform passes over the final two sites at lower altitudes and take even higher resolution observations of the surface to identify features, such as groupings of rocks that will be used to navigate to the surface for sample collection. OSIRIS-REx sample collection is scheduled for the latter half of 2020, and the spacecraft will return the asteroid samples to Earth on Sept. 24, 2023.

    Goddard provides overall mission management, systems engineering, and safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

    To explore the final four candidate sites in detail, click here.

  43. Asteroid Bennu’s Features To Be Named After Mythical Birds

    August 8, 2019 -

    Working with NASA’s OSIRIS-REx team, the International Astronomical Union’s Working Group for Planetary System Nomenclature (WGPSN) approved the theme “birds and bird-like creatures in mythology” for naming surface features on asteroid (101955) Bennu.

    This image shows boulder formations on asteroid Bennu’s surface. It was taken by the PolyCam camera on NASA’s OSIRIS-REx spacecraft on April 11, 2019 from a distance of 2.8 miles (4.5 km). Credit: NASA/Goddard/University of Arizona

    OSIRIS-REx is NASA’s first mission to bring a sample from an asteroid back to Earth. The OSIRIS-REx spacecraft has been mapping Bennu’s surface since its arrival on December 3rd, 2018, looking for a site from which to take a sample. Bennu is the smallest body in the Solar System to be orbited and surveyed by a spacecraft at close range.

    The named features on Bennu will include several terrain classification types that the IAU also approved for asteroid (162173) Ryugu’s surface features (currently being explored by the Japanese Space Agency’s Hayabusa2 spacecraft). These include craters, dorsa (peaks or ridges), fossae (grooves or trenches) and saxa (rocks and boulders). The last of these types – saxum – is a new feature classification that the IAU introduced earlier this year for small, rocky asteroids like Ryugu and Bennu. These surface features on Bennu will be named after mythological birds and bird-like creatures, complementing the mission’s existing naming theme, which is rooted in Egyptian mythology.

    The name OSIRIS-REx is an acronym for the mission’s major concepts and goals, which stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. The name also finds inspiration in the Egyptian myth of the god Osiris. In ancient Egyptian mythology, Osiris is associated with the afterlife, the underworld and rebirth. He granted all life, including sprouting vegetation and the fertile flooding of the Nile River. Similarly, the OSIRIS-REx mission seeks to understand the origin and process of life on Earth by studying Bennu’s carbon-rich regolith.

    Bennu was named in 2013 by a 9-year-old boy from North Carolina who won the Name that Asteroid! Competition, a collaboration between the mission, the Planetary Society, and the LINEAR asteroid survey that discovered Bennu. Michael Puzio won the contest by suggesting that the spacecraft’s Touch-and-Go Sample Mechanism (TAGSAM) arm and solar panels resemble the neck and wings in illustrations of Bennu, whom ancient Egyptians usually depicted as a gray heron. Bennu is the ancient Egyptian deity linked with the Sun, creation and rebirth — Puzio also noted that Bennu is the living symbol of Osiris. The myth of Bennu suits the asteroid itself, given that it is a primitive object that dates back to the creation of the Solar System. Themes of origins, rebirth and duality are all part of this asteroid’s story. Birds and bird-like creatures are also symbolic of rebirth, creation and origins in various ancient myths.

    The process of naming of Bennu’s surface and features will begin this summer. The OSIRIS-REx team is scheduled to begin detailed reconnaissance on candidate sample sites this fall. Sample collection is scheduled for summer 2020, and the sample will return to Earth in September 2023.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  44. NASA’s OSIRIS-REx Mission Breaks Another Orbit Record

    June 13, 2019 -

    On June 12, NASA’s OSIRIS-REx spacecraft performed another significant navigation maneuver—breaking its own world record for the closest orbit of a planetary body by a spacecraft.

    On Jun. 12, 2019, NASA’s OSIRIS-REx spacecraft went into orbit around asteroid Bennu for a second time — breaking its own record for the closest orbit of a planetary body by any spacecraft.

    The maneuver began the mission’s new phase, known as Orbital B, and placed the spacecraft in an orbit 680 meters (2,231 feet) above the surface of asteroid Bennu. The previous record—also set by the OSIRIS-REx spacecraft—was approximately 1.3 kilometers (0.8 miles) above the surface.

    Upon arrival at Bennu, the team observed particles ejecting into space from the asteroid’s surface. To better understand why this is occurring, the first two weeks of Orbital B will be devoted to observing these events by taking frequent images of the asteroid’s horizon. For the remaining five weeks, the spacecraft will map the entire asteroid using most of its onboard science instruments: the OSIRIS-REx Laser Altimeter (OLA) will produce a full terrain map; PolyCam will form a high-resolution, global image mosaic; and the OSIRIS-REx Thermal Emission Spectrometer (OTES) and the REgolith X-ray Imaging Spectrometer (REXIS) will produce global maps in the infrared and X-ray bands. All of these measurements are essential for selecting the best sample collection site on Bennu’s surface.

    OSIRIS-REx will remain in Orbital B until the second week of August, when it will transition to the slightly higher Orbital C for additional particle observations. During Orbital C, the spacecraft will be approximately 1.3 kilometers (0.8 miles) above the asteroid’s surface.

    The OSIRIS-REx team will also use data collected from Orbital B phase to assess the safety and sample-ability (the likelihood that a sample can be collected) of each potential sample collection site. The team will then choose four possible sample sites to be thoroughly evaluated this fall during the Reconnaissance phase of the mission. Data from the Reconnaissance phase will be used to evaluate the candidate sites for further down-selection, as well as provide the closeup imaging required to map the features and landmarks necessary for the spacecraft’s autonomous navigation to the asteroid’s surface.

    On June 12, 2019, NASA’s OSIRIS-REx spacecraft entered its second orbital phase around asteroid Bennu, called Orbital B, and broke its own world record for the closest orbit of a planetary body. The spacecraft moved into a circular orbit 0.4 miles (680 meters) above Bennu’s surface. The previous record was set by OSIRIS-REx on Dec. 31, 2018, when the spacecraft flew 0.8 miles (1.33 km) above the asteroid’s surface during Orbital A phase.

    Several safety requirements must be considered before sample collection. For instance, any candidate site must be clear enough of large rocks or boulders so that the spacecraft can navigate to the surface without encountering dangerous terrain. Additionally, to keep OSIRIS-REx upright during sample collection, the chosen site can’t be tilted too much compared to the sampling arm. Bennu’s unexpectedly rocky surface has made it more challenging than originally predicted to identify sites that meet both of these safety requirements. In response, the team is evaluating both spacecraft and navigation performance capabilities, which will likely enable greater precision guidance to target more confined sites.

    The OSIRIS-REx spacecraft is on a seven-year journey to study the asteroid Bennu and return a sample from its surface to Earth. This sample of a primitive asteroid will help scientists understand the formation of the Solar System over 4.5 billion years ago. Sample collection is scheduled for summer of 2020, and the spacecraft will deliver the sample to Earth in September 2023.

    NASA Goddard provides overall mission management, systems engineering, and safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  45. NASA Invites Public to Help Asteroid Mission Choose Sample Site

    May 22, 2019 -

    Citizen scientists assemble! NASA’s OSIRIS-REx mission to the asteroid Bennu needs extra pairs of eyes to help choose its sample collection site on the asteroid – and to look for anything else that might be scientifically interesting.

    This image shows the wide variety of boulder shapes, sizes and compositions found on asteroid Bennu. It was taken by the PolyCam camera on NASA’s OSIRIS-REx spacecraft on March 28 from a distance of 2.1 miles (3.4 km). Credit: NASA/Goddard/University of Arizona

    The OSIRIS-REx spacecraft has been at Bennu since Dec. 3, 2018, mapping the asteroid in detail, while the mission team searches for a sample collection site that is safe, conducive to sample collection and worthy of closer study. One of the biggest challenges of this effort, which the team discovered after arriving at the asteroid five months ago, is that Bennu has an extremely rocky surface and each boulder presents a danger to the spacecraft’s safety. To expedite the sample selection process, the team is asking citizen scientist volunteers to develop a hazard map by counting boulders.

    “For the safety of the spacecraft, the mission team needs a comprehensive catalog of all the boulders near the potential sample collection sites, and I invite members of the public to assist the OSIRIS-REx mission team in accomplishing this essential task,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson.

    For this effort, NASA is partnering with CosmoQuest, a project run out of the Planetary Science Institute that supports citizen science initiatives. Volunteers will perform the same tasks that planetary scientists do – measuring Bennu’s boulders and mapping its rocks and craters – through the use of a simple web interface. They will also mark other scientifically interesting features on the asteroid for further investigation.

    The boulder mapping work involves a high degree of precision, but it is not difficult. The CosmoQuest mapping app requires a computer with a larger screen and a mouse or trackpad capable of making precise marks. To help volunteers get started, the CosmoQuest team provides an interactive tutorial, as well as additional user assistance through a Discord community and livestreaming sessions on Twitch.

    “We are very pleased and excited to make OSIRIS-REx images available for this important citizen science endeavor,” said Rich Burns, OSIRIS-REx project manager at NASA Goddard Space Flight Center. “Bennu has surprised us with an abundance of boulders. We ask for citizen scientists’ help to evaluate this rugged terrain so that we can keep our spacecraft safe during sample collection operations.”

    This image shows a view of asteroid Bennu’s surface in a region near the equator. It was taken by the PolyCam camera on NASA’s OSIRIS-REx spacecraft on March 21 from a distance of 2.2 miles (3.5 km). Credit: NASA/Goddard/University of Arizona

    Sample return isn’t new for NASA – this year, the agency is celebrating the 50th anniversary of the Apollo missions to the Moon, which allowed astronauts to bring back 842 pounds (382 kilograms) of rocks and lunar soil. Those samples helped scientists discover that the Moon has water locked in its rocks and even permanently frozen in craters. These findings and others inspired the agency to create the Artemis program to return humans to the Moon by 2024 and start preparing for human exploration on Mars.

    “The OSIRIS-REx mission will continue the Apollo legacy by giving scientists precious samples of an asteroid,” said Lori Glaze, director of the Planetary Science Division at NASA Headquarters in Washington. “These samples will help scientists discover the secrets of planetary formation and the origins of our planet Earth.”

    The Bennu mapping campaign continues through July 10, when the mission begins the sample site selection process. Once primary and secondary sites are selected, the spacecraft will begin closer reconnaissance to map the two sites to sub-centimeter resolution. The mission’s Touch-and-Go (TAG) sampling maneuver is scheduled for July 2020, and the spacecraft will return to Earth with its cargo in September 2023.

    Goddard provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

    To volunteer as a Bennu mapper, visit:

    Bennu.cosmoquest.org

  46. OSIRIS-REx Special Collection in Nature

    March 26, 2019 -

    When NASA’s OSIRIS-REx spacecraft arrived at asteroid Bennu on Dec. 3, 2018, it found a tiny world that in many respects was as the mission team had expected based on ground-based observations — but the team also found that Bennu held quite a few surprises, too. On March 19, 2019, Nature­ published a special collection of eight papers from the OSIRIS-REx mission team providing a first look at asteroid Bennu. The following provides the key findings published in those scientific papers. The full Nature collection may be accessed directly here.

    Global elevation map of asteroid Bennu. Credit: NASA/Goddard/University of Arizona

    Lauretta and DellaGiustina et al.The unexpected surface of asteroid (101955) Bennu.Nature.

    NASA’s OSIRIS-REx spacecraft recently arrived at Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth. Bennu is a low-albedo B-type asteroid that has been linked to organic-rich hydrated carbonaceous chondrites. Such meteorites are altered by ejection from their parent body and contaminated by atmospheric entry and terrestrial microbes. Therefore, the primary mission objective is to return a sample of Bennu to Earth that is pristine—that is, not affected by these processes. The OSIRIS-REx spacecraft carries a sophisticated suite of instruments to characterize Bennu’s global properties, support the selection of a sampling site and document that site at a sub-centimeter scale. Here we consider early OSIRIS-REx observations of Bennu to understand how the asteroid’s properties compare to pre-encounter expectations and to assess the prospects for sample return. The bulk composition of Bennu appears to be hydrated and volatile-rich, as expected. However, in contrast to pre-encounter modelling of Bennu’s thermal inertia and radar polarization ratios—which indicated a generally smooth surface covered by centimeter-scale particles—resolved imaging reveals an unexpected surficial diversity. The albedo, texture, particle size and roughness are beyond the spacecraft design specifications. On the basis of our pre-encounter knowledge, we developed a sampling strategy to target 50-meter-diameter patches of loose regolith with grain sizes smaller than two centimeters. We observe only a small number of apparently hazard-free regions, of the order of 5 to 20 meters in extent, the sampling of which poses a substantial challenge to mission success.

     

    Barnouin et al.Shape of (101955) Bennu indicative of a rubble pile with internal stiffness.Nature Geoscience.

    The shapes of asteroids reflect interplay between their interior properties and the processes responsible for their formation and evolution as they journey through the Solar System. Prior to the OSIRIS-REx mission, Earth-based radar imaging gave an overview of Bennu’s shape. Here we construct a high-resolution shape model from OSIRIS-REx images. We find that Bennu’s top-like shape, considerable macroporosity and prominent surface boulders suggest that it is a rubble pile. High-standing, north–south ridges that extend from pole to pole, many long grooves and surface mass wasting indicate some low levels of internal friction and/or cohesion. Our shape model indicates that, similar to other top-shaped asteroids, Bennu formed by reaccumulation and underwent past periods of fast spin, which led to its current shape. Today, Bennu might follow a different evolutionary pathway, with an interior stiffness that permits surface cracking and mass wasting.

     

    DellaGiustina and Emery et al.Properties of rubble-pile asteroid (101955) Bennu from OSIRIS-REx imaging and thermal analysis.Nature Astronomy.

    Establishing the abundance and physical properties of regolith and boulders on asteroids is crucial for understanding the formation and degradation mechanisms at work on their surfaces. Using images and thermal data from NASA’s OSIRIS-REx spacecraft, we show that asteroid Bennu’s surface is globally rough, dense with boulders, and low in albedo. The number of boulders is surprising given Bennu’s moderate thermal inertia, suggesting that simple models linking thermal inertia to particle size do not adequately capture the complexity relating these properties. At the same time, we find evidence for a wide range of particle sizes with distinct albedo characteristics. Our findings imply that ages of Bennu’s surface particles span from the disruption of the asteroid’s parent body (boulders) to recent in situ production (micrometer-scale particles).

     

    Hamilton et al.Evidence for widespread hydrated minerals on asteroid (101955) Bennu.Nature Astronomy.

    Early spectral data from the OSIRIS-REx mission reveal evidence for abundant hydrated minerals on the surface of near-Earth asteroid Bennu in the form of a near-infrared absorption near 2.7 µm and thermal infrared spectral features that are most similar to those of aqueously altered CM-type carbonaceous chondrites. We observe these spectral features across the surface of Bennu, and there is no evidence of substantial rotational variability at the spatial scales of tens to hundreds of metres observed to date. In the visible and near-infrared (0.4 to 2.4 µm) Bennu’s spectrum appears featureless and with a blue (negative) slope, confirming previous ground-based observations. Bennu may represent a class of objects that could have brought volatiles and organic chemistry to Earth.

     

    Hergenrother et al.Operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations.Nature Communications [open access].

    During its approach to asteroid Bennu, NASA’s OSIRIS-REx spacecraft surveyed Bennu’s immediate environment, photometric properties, and rotation state. Discovery of a dusty environment, a natural satellite, or unexpected asteroid characteristics would have had consequences for the mission’s safety and observation strategy. Here we show that spacecraft observations during this period were highly sensitive to satellites (sub-meter scale) but reveal none, although later navigational images indicate that further investigation is needed. We constrain average dust production in September 2018 from Bennu’s surface to an upper limit of 150 g s–1 averaged over 34 min. Bennu’s disk-integrated photometric phase function validates measurements from the pre-encounter astronomical campaign. We demonstrate that Bennu’s rotation rate is accelerating continuously at 3.63 ± 0.52 × 10–6 degrees day–2, likely due to the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, with evolutionary implications.

     

    Scheeres et al.The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx measurements.Nature Astronomy.

    The top-shaped morphology characteristic of asteroid Bennu, often found among fast-spinning asteroids and binary asteroid primaries, may have contributed substantially to binary asteroid formation. Yet a detailed geophysical analysis of this morphology for a fast-spinning asteroid has not been possible prior to the OSIRIS-REx mission. Combining the measured Bennu mass and shape obtained during the Preliminary Survey phase of the OSIRIS-REx mission, we find a notable transition in Bennu’s surface slopes within its rotational Roche lobe, defined as the region where material is energetically trapped to the surface. As the intersection of the rotational Roche lobe with Bennu’s surface has been most recently migrating towards its equator (given Bennu’s increasing spin rate), we infer that Bennu’s surface slopes have been changing across its surface within the last million years. We also find evidence for substantial density heterogeneity within this body, suggesting that its interior is a mixture of voids and boulders. The presence of such heterogeneity and Bennu’s top shape are consistent with spin-induced failure at some point in its past, although the manner of its failure cannot yet be determined. Future measurements by the OSIRIS-REx spacecraft will provide insight into and may resolve questions regarding the formation and evolution of Bennu’s top-shape morphology and its link to the formation of binary asteroids.

     

    Walsh et al. Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface.Nature Geoscience.

    Small, kilometer-sized near-Earth asteroids are expected to have young and frequently refreshed surfaces for two reasons: collisional disruptions are frequent in the main asteroid belt where they originate, and thermal or tidal processes act on them once they become near-Earth asteroids. Here we present early measurements of numerous large candidate impact craters on near-Earth asteroid Bennu by the OSIRIS-REx mission, which indicate a surface that is between 100 million and 1 billion years old, predating Bennu’s expected duration as a near-Earth asteroid. We also observe many fractured boulders, the morphology of which suggests an influence of impact or thermal processes over a considerable amount of time since the boulders were exposed at the surface. However, the surface also shows signs of more recent mass movement: clusters of boulders at topographic lows, a deficiency of small craters and infill of large craters. The oldest features likely record events from Bennu’s time in the main asteroid belt.

     

     Enos and Lauretta. A rendezvous with asteroid Bennu.Nature Astronomy.

    The OSIRIS-REx mission has reached its target, asteroid Bennu, and is engaging in reconnaissance and early science observations in preparation for sample collection. Principal investigator team Heather Enos and Dante Lauretta provide an overview.

  47. NASA Mission Reveals Asteroid Has Big Surprises

    March 19, 2019 -

    A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid’s surface. Bennu also revealed itself to be more rugged than expected, challenging the mission team to alter its flight and sample collection plans, due to the rough terrain.

    This view of asteroid Bennu ejecting particles from its surface on January 19 was created by combining two images taken by the NavCam 1 imager onboard NASA’s OSIRIS-REx spacecraft: a short exposure image (1.4 ms), which shows the asteroid clearly, and a long exposure image (5 sec), which shows the particles clearly. Other image processing techniques were also applied, such as cropping and adjusting the brightness and contrast of each layer. Credit: NASA/Goddard/University of Arizona/Lockheed Martin

    Bennu is the target of NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission, which began orbiting the asteroid on Dec. 31. Bennu, which is only slightly wider than the height of the Empire State Building, may contain unaltered material from the very beginning of our solar system.

    “The discovery of plumes is one of the biggest surprises of my scientific career,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “And the rugged terrain went against all of our predictions. Bennu is already surprising us, and our exciting journey there is just getting started.”

    Shortly after the discovery of the particle plumes on Jan. 6, the mission science team increased the frequency of observations, and subsequently detected additional particle plumes — also known as “ejection events” — during the following two months. Although many of the particles were ejected clear of Bennu, the team tracked some particles that orbited Bennu as satellites before returning to the asteroid’s surface.

    The OSIRIS-REx team initially spotted the particle ejection events in images while the spacecraft was orbiting Bennu at a distance of about one mile (1.61 kilometers). Following a safety assessment, the mission team concluded the particles did not pose a risk to the spacecraft. The team continues to analyze the particle ejection eventsand their possible causes.

    “The first three months of OSIRIS-REx’s up-close investigation of Bennu have reminded us what discovery is all about — surprises, quick thinking, and flexibility,” said Lori Glaze, acting director of the Planetary Science Division at NASA Headquarters in Washington. “We study asteroids like Bennu to learn about the origin of the solar system. OSIRIS-REx’s sample will help us answer some of the biggest questions about where we come from.”

    OSIRIS-REx launched in 2016 to explore Bennu, which is the smallest body ever orbited by spacecraft. Studying Bennu will allow researchers to learn more about the origins of our solar system, the sources of water and organic molecules on Earth, the resources in near-Earth space, as well as improve our understanding of asteroids that could impact Earth.

    This image shows a view across asteroid Bennu’s southern hemisphere and into space, and it demonstrates the number and distribution of boulders across Bennu’s surface. The image was obtained on Mar. 7 by the PolyCam camera on NASA’s OSIRIS-REx spacecraft from a distance of about 3 miles (5 km). The large, light-colored boulder just below the center of the image is about 24 feet (7.4 meters) wide, which is roughly half the width of a basketball court. Credit: NASA/Goddard/University of Arizona

    The OSIRIS-REx team also didn’t anticipate the number and size of boulders on Bennu’s surface. From Earth-based observations, the team expected a generally smooth surface with a few large boulders. Instead, it discovered Bennu’s entire surface is rough and dense with boulders.

    The higher-than-expected density of boulders means that the mission’s plans for sample collection, also known as Touch-and-Go (TAG), need to be adjusted. The original mission design was based on a sample site that is hazard-free, with an 82-foot (25-meter) radius. However, because of the unexpectedly rugged terrain, the team hasn’t been able to identify a site of that size on Bennu. Instead, it has begun to identify candidate sites that are much smaller in radius.

    The smaller sample site footprint and the greater number of boulders will demand more accurate performance from the spacecraft during its descent to the surface than originally planned. The mission team is developing an updated approach, called Bullseye TAG, to accurately target smaller sample sites.

    “Throughout OSIRIS-REx’s operations near Bennu, our spacecraft and operations team have demonstrated that we can achieve system performance that beats design requirements,” said Rich Burns, the project manager of OSIRIS-REx at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Bennu has issued us a challenge to deal with its rugged terrain, and we are confident that OSIRIS-REx is up to the task.”

    The original, low-boulder estimate was derived both from Earth-based observations of Bennu’s thermal inertia — or its ability to conduct and store heat — and from radar measurements of its surface roughness. Now that OSIRIS-REx has revealed Bennu’s surface up close, those expectations of a smoother surface have been proven wrong. This suggests the computer models used to interpret previous data do not adequately predict the nature of small, rocky, asteroid surfaces. The team is revising these models with the data from Bennu.

    The OSIRIS-REx science team has made many other discoveries about Bennu in the three months since the spacecraft arrived at the asteroid, some of which were presented Tuesday at the 50th Lunar and Planetary Conference in Houston and in a special collection of papers issued by the journal Nature.

    The team has directly observed a change in the spin rate of Bennu as a result of what is known as the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect. The uneven heating and cooling of Bennu as it rotates in sunlight is causing the asteroid to increase its rotation speed. As a result, Bennu’s rotation period is decreasing by about one second every 100 years. Separately, two of the spacecraft’s instruments, the MapCam color imager and the OSIRIS-REx Thermal Emission Spectrometer (OTES), have made detections of magnetite on Bennu’s surface, which bolsters earlier findings indicating the interaction of rock with liquid water on Bennu’s parent body.

    Goddard provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

  48. NASA’s OSIRIS-REx Spacecraft Enters Orbit Around Bennu, Breaking Record

    By Lonnie Shekhtman

    January 2, 2019 -

    On Dec. 31, 2018, NASA’s OSIRIS-REx spacecraft went into orbit around asteroid Bennu for the first time – — setting new records for the smallest body ever orbited by a spacecraft and the closest orbit of a planetary body by any spacecraft.

    At 2:43 p.m. EST on December 31, while many on Earth prepared to welcome the New Year, NASA’s OSIRIS-REx spacecraft, 70 million miles (110 million kilometers) away, carried out a single, eight-second burn of its thrusters – and broke a space exploration record. The spacecraft entered into orbit around the asteroid Bennu, and made Bennu the smallest object ever to be orbited by a spacecraft.

    “The team continued our long string of successes by executing the orbit-insertion maneuver perfectly,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “With the navigation campaign coming to an end, we are looking forward to the scientific mapping and sample site selection phase of the mission.”

    Lauretta, along with his team, spent the last day of 2018 with his feet planted on Earth, but his mind focused on space. “Entering orbit around Bennu is an amazing accomplishment that our team has been planning for years,” Lauretta said.

    Inching around the asteroid at a snail’s pace, OSIRIS-REx’s first orbit marks a leap for humankind. Never before has a spacecraft from Earth circled so close to such a small space object – one with barely enough gravity to keep a vehicle in a stable orbit.

    Now, the spacecraft will circle Bennu about a mile (1.75 kilometers) from its center, closer than any other spacecraft has come to its celestial object of study. (Previously the closest orbit of a planetary body was in May 2016, when the Rosetta spacecraft orbited about four miles (seven kilometers) from the center of the comet 67P/Churyumov-Gerasimenko.) The comfortable distance is necessary to keep the spacecraft locked to Bennu, which has a gravity force only 5-millionths as strong as Earth’s. The spacecraft is scheduled to orbit Bennu through mid-February at a leisurely 62 hours per orbit.

    Now that the OSIRIS-REx spacecraft is closer to Bennu, physical details about the asteroid will leap into sharper focus, and the spacecraft’s tour of this rubble pile of primordial debris will become increasingly detailed and focused.

    “Our orbit design is highly dependent on Bennu’s physical properties, such as its mass and gravity field, which we didn’t know before we arrived,” said OSIRIS-REx’s flight dynamics system manager Mike Moreau, who is based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

    “Up until now, we had to account for a wide variety of possible scenarios in our computer simulations to make sure we could safely navigate the spacecraft so close to Bennu. As the team learned more about the asteroid, we incorporated new information to hone in on the final orbit design,” he said.

    The simulations have played a critical role. The OSIRIS-REx mission, after all, was designed based on complex computer programs that predicted — quite accurately, as it turns out — the properties of Bennu and how the spacecraft’s trajectory would behave. This diligent preparation allowed the team to navigate the vehicle safely to Bennu in December and put some questions to rest (there are, indeed, signs of ancient water preserved in Bennu’s rocks) and to fly over its poles and equator in a preliminary survey that led to some surprises (Bennu has many large boulders).

    Having completed the preliminary survey of Bennu with a flyby of its south pole on December 16, the spacecraft moved to a safe 31 miles (50 kilometers) away from the asteroid to give the navigation team a chance to regroup and prepare for orbit insertion. Next, Lockheed Martin engineers programmed the spacecraft to begin moving back to a position about nine miles (15 kilometers) over Bennu’s north pole to prepare for three burns of its thrusters over the course of 10 days that would place the spacecraft into orbit.

    Even though OSIRIS-REx is in the most stable orbit possible, Bennu’s gravitational pull is so tenuous that keeping the spacecraft safe will require occasional adjustments, said Dan Wibben, OSIRIS-REx maneuver and trajectory design lead at KinetX Aerospace in Simi Valley, California.

    “The gravity of Bennu is so small, forces like solar radiation and thermal pressure from Bennu’s surface become much more relevant and can push the spacecraft around in its orbit much more than if it were orbiting around Earth or Mars, where gravity is by far the most dominant force,” he said.

    The OSIRIS-REx navigation team will use “trim” maneuvers to slightly thrust the spacecraft in one direction or another to correct its orbit and counter these small forces. If the spacecraft drifts away from Bennu, or some other problem forces it into safe mode, it has been programmed to fly away from the asteroid to stay safe from impact.

    “It’s simple logic: always burn toward the Sun if something goes wrong,” said Coralie Adam, OSIRIS-REx lead optical navigation engineer at KinetX. Engineers can navigate the spacecraft back into orbit if it drifts away, Adam said, though that’s unlikely to happen.

    The navigation and spacecraft operations teams are focused on the first orbital phase. Their primary goal is to transition away from star-based navigation, which allowed the team to locate the spacecraft based on pictures of the star formations around it taken by the cameras onboard. Navigators use methods like this since there is no GPS in deep space and we can’t see the spacecraft from Earth-based telescopes. From this point forward, though, the OSIRIS-REx team will rely on landmarks on Bennu’s surface to track OSIRIS-REx, a more precise technique that will ultimately guide them to a sample-collection site clear of boulders and large rocks, said Adam.

    “After conducting a global imaging and mapping campaign during our recent preliminary survey phase, the science team has created 3-D models of Bennu’s terrain that we’re going to begin using for navigation around the asteroid,” she said.

    Another critical objective of this orbital phase, Adam said, is to get a better handle on Bennu’s mass and gravity, features that will influence the planning of the rest of the mission, notably the short touchdown on the surface for sample collection in 2020. In the case of Bennu, scientists can only measure these features by getting OSIRIS-REx very close to the surface to see how its trajectory bends from Bennu’s gravitational pull.

    “The Orbital A phase will help improve our detailed models for Bennu’s gravity field, thermal properties, orientation, and spin rate,” said Wibben. “This, in turn, will allow us to refine our trajectory designs for the even more challenging flight activities we will perform in 2019.”

    The December 31 maneuver to place the spacecraft into orbit about Bennu is the first of many exciting navigation activities planned for the mission. The OSIRIS-REx team will resume science operations in late February. At that point, the spacecraft will perform a series of close flybys of Bennu for several months to take high-resolution images of every square inch of the asteroid to help select a sampling site. During the summer of 2020, the spacecraft will briefly touch the surface of Bennu to retrieve a sample. The OSIRIS-REx mission is scheduled to deliver the sample to Earth in September 2023.

    Goddard provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama for the agency’s Science Mission Directorate in Washington.

  49. NASA’s OSIRIS-REx Spacecraft Enters Close Orbit Around Bennu, Breaking Record

    By Lonnie Shekhtman

    December 31, 2018 -

    On Dec. 31, 2018, NASA’s OSIRIS-REx spacecraft went into orbit around asteroid Bennu for the first time.

    At 2:43 p.m. EST on December 31, while many on Earth prepared to welcome the New Year, NASA’s OSIRIS-REx spacecraft, 70 million miles (110 million kilometers) away, carried out a single, eight-second burn of its thrusters – and broke a space exploration record. The spacecraft entered into orbit around the asteroid Bennu, and made Bennu the smallest object ever to be orbited by a spacecraft.

    “The team continued our long string of successes by executing the orbit-insertion maneuver perfectly,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “With the navigation campaign coming to an end, we are looking forward to the scientific mapping and sample site selection phase of the mission.”

    Lauretta, along with his team, spent the last day of 2018 with his feet planted on Earth, but his mind focused on space. “Entering orbit around Bennu is an amazing accomplishment that our team has been planning for years,” Lauretta said.

    Inching around the asteroid at a snail’s pace, OSIRIS-REx’s first orbit marks a leap for humankind. Never before has a spacecraft from Earth circled so close to such a small space object – one with barely enough gravity to keep a vehicle in a stable orbit.

    Now, the spacecraft will circle Bennu about a mile (1.75 kilometers) from its center, closer than any other spacecraft has come to its celestial object of study. (Previously the closest orbit of a planetary body was in May 2016, when the Rosetta spacecraft orbited about four miles (seven kilometers) from the center of the comet 67P/Churyumov-Gerasimenko.) The comfortable distance is necessary to keep the spacecraft locked to Bennu, which has a gravity force only 5-millionths as strong as Earth’s. The spacecraft is scheduled to orbit Bennu through mid-February at a leisurely 62 hours per orbit.

    Now that the OSIRIS-REx spacecraft is closer to Bennu, physical details about the asteroid will leap into sharper focus, and the spacecraft’s tour of this rubble pile of primordial debris will become increasingly detailed and focused.

    “Our orbit design is highly dependent on Bennu’s physical properties, such as its mass and gravity field, which we didn’t know before we arrived,” said OSIRIS-REx’s flight dynamics system manager Mike Moreau, who is based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

    “Up until now, we had to account for a wide variety of possible scenarios in our computer simulations to make sure we could safely navigate the spacecraft so close to Bennu. As the team learned more about the asteroid, we incorporated new information to hone in on the final orbit design,” he said.

    The simulations have played a critical role. The OSIRIS-REx mission, after all, was designed based on complex computer programs that predicted — quite accurately, as it turns out — the properties of Bennu and how the spacecraft’s trajectory would behave. This diligent preparation allowed the team to navigate the vehicle safely to Bennu in December and put some questions to rest (there are, indeed, signs of ancient water preserved in Bennu’s rocks) and to fly over its poles and equator in a preliminary survey that led to some surprises (Bennu has many large boulders).

    Having completed the preliminary survey of Bennu with a flyby of its south pole on December 16, the spacecraft moved to a safe 31 miles (50 kilometers) away from the asteroid to give the navigation team a chance to regroup and prepare for orbit insertion. Next, Lockheed Martin engineers programmed the spacecraft to begin moving back to a position about nine miles (15 kilometers) over Bennu’s north pole to prepare for three burns of its thrusters over the course of 10 days that would place the spacecraft into orbit.

    Even though OSIRIS-REx is in the most stable orbit possible, Bennu’s gravitational pull is so tenuous that keeping the spacecraft safe will require occasional adjustments, said Dan Wibben, OSIRIS-REx maneuver and trajectory design lead at KinetX Aerospace in Simi Valley, California.

    “The gravity of Bennu is so small, forces like solar radiation and thermal pressure from Bennu’s surface become much more relevant and can push the spacecraft around in its orbit much more than if it were orbiting around Earth or Mars, where gravity is by far the most dominant force,” he said.

    The OSIRIS-REx navigation team will use “trim” maneuvers to slightly thrust the spacecraft in one direction or another to correct its orbit and counter these small forces. If the spacecraft drifts away from Bennu, or some other problem forces it into safe mode, it has been programmed to fly away from the asteroid to stay safe from impact.

    “It’s simple logic: always burn toward the Sun if something goes wrong,” said Coralie Adam, OSIRIS-REx lead optical navigation engineer at KinetX. Engineers can navigate the spacecraft back into orbit if it drifts away, Adam said, though that’s unlikely to happen.

    The navigation and spacecraft operations teams are focused on the first orbital phase. Their primary goal is to transition away from star-based navigation, which allowed the team to locate the spacecraft based on pictures of the star formations around it taken by the cameras onboard. Navigators use methods like this since there is no GPS in deep space and we can’t see the spacecraft from Earth-based telescopes. From this point forward, though, the OSIRIS-REx team will rely on landmarks on Bennu’s surface to track OSIRIS-REx, a more precise technique that will ultimately guide them to a sample-collection site clear of boulders and large rocks, said Adam.

    “After conducting a global imaging and mapping campaign during our recent preliminary survey phase, the science team has created 3-D models of Bennu’s terrain that we’re going to begin using for navigation around the asteroid,” she said.

    Another critical objective of this orbital phase, Adam said, is to get a better handle on Bennu’s mass and gravity, features that will influence the planning of the rest of the mission, notably the short touchdown on the surface for sample collection in 2020. In the case of Bennu, scientists can only measure these features by getting OSIRIS-REx very close to the surface to see how its trajectory bends from Bennu’s gravitational pull.

    “The Orbital A phase will help improve our detailed models for Bennu’s gravity field, thermal properties, orientation, and spin rate,” said Wibben. “This, in turn, will allow us to refine our trajectory designs for the even more challenging flight activities we will perform in 2019.”

    The December 31 maneuver to place the spacecraft into orbit about Bennu is the first of many exciting navigation activities planned for the mission. The OSIRIS-REx team will resume science operations in late February. At that point, the spacecraft will perform a series of close flybys of Bennu for several months to take high-resolution images of every square inch of the asteroid to help select a sampling site. During the summer of 2020, the spacecraft will briefly touch the surface of Bennu to retrieve a sample. The OSIRIS-REx mission is scheduled to deliver the sample to Earth in September 2023.

    Goddard provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama for the agency’s Science Mission Directorate in Washington.

  50. NASA’s Newly Arrived OSIRIS-REx Spacecraft Already Discovers Water on Asteroid

    December 10, 2018 -

    Recently analyzed data from NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission has revealed water locked inside the clays that make up its scientific target, the asteroid Bennu.

    This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2 by the OSIRIS-REx spacecraft from a range of 15 miles (24 km).
    Credit: NASA/Goddard/University of Arizona

    During the mission’s approach phase, between mid-August and early December, the spacecraft traveled 1.4 million miles (2.2 million km) on its journey from Earth to arrive at a location 12 miles (19 km) from Bennu on Dec. 3. During this time, the science team on Earth aimed three of the spacecraft’s instruments towards Bennu and began making the mission’s first scientific observations of the asteroid. OSIRIS-REx is NASA’s first asteroid sample return mission.

    Data obtained from the spacecraft’s two spectrometers, the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) and the OSIRIS-REx Thermal Emission Spectrometer (OTES), reveal the presence of molecules that contain oxygen and hydrogen atoms bonded together, known as “hydroxyls.” The team suspects that these hydroxyl groups exist globally across the asteroid in water-bearing clay minerals, meaning that at some point, Bennu’s rocky material interacted with water. While Bennu itself is too small to have ever hosted liquid water, the finding does indicate that liquid water was present at some time on Bennu’s parent body, a much larger asteroid.

    “The presence of hydrated minerals across the asteroid confirms that Bennu, a remnant from early in the formation of the solar system, is an excellent specimen for the OSIRIS-REx mission to study the composition of primitive volatiles and organics,” said Amy Simon, OVIRS deputy instrument scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system.”

    Additionally, data obtained from the OSIRIS-REx Camera Suite (OCAMS) corroborate ground-based telescopic observations of Bennu and confirm the original model developed in 2013 by OSIRIS-REx Science Team Chief Michael Nolan and collaborators. That model closely predicted the asteroid’s actual shape, with Bennu’s diameter, rotation rate, inclination, and overall shape presented almost exactly as projected.

    This preliminary shape model of asteroid Bennu was created from a compilation of images taken by OSIRIS-REx’s PolyCam camera during the spacecraft’s approach toward Bennu during the month of November. This 3D shape model shows features on Bennu as small as six meters.
    Credit: NASA/Goddard/University of Arizona

    One outlier from the predicted shape model is the size of the large boulder near Bennu’s south pole. The ground-based shape model calculated this boulder to be at least 33 feet (10 meters) in height. Preliminary calculations from OCAMS observations show that the boulder is closer to 164 feet (50 meters) in height, with a width of approximately 180 feet (55 meters).

    Bennu’s surface material is a mix of very rocky, boulder-filled regions and a few relatively smooth regions that lack boulders. However, the quantity of boulders on the surface is higher than expected. The team will make further observations at closer ranges to more accurately assess where a sample can be taken on Bennu to later be returned to Earth.

    “Our initial data show that the team picked the right asteroid as the target of the OSIRIS-REx mission. We have not discovered any insurmountable issues at Bennu so far,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “The spacecraft is healthy and the science instruments are working better than required. It is time now for our adventure to begin.”

    The mission currently is performing a preliminary survey of the asteroid, flying the spacecraft in passes over Bennu’s north pole, equator, and south pole at ranges as close as 4.4 miles (7 km) to better determine the asteroid’s mass. The mission’s scientists and engineers must know the mass of the asteroid in order to design the spacecraft’s insertion into orbit because mass affects the asteroid’s gravitational pull on the spacecraft. Knowing Bennu’s mass will also help the science team understand the asteroid’s structure and composition.

    This survey also provides the first opportunity for the OSIRIS-REx Laser Altimeter (OLA), an instrument contributed by the Canadian Space Agency, to make observations, now that the spacecraft is in proximity to Bennu.

    The spacecraft’s first orbital insertion is scheduled for Dec. 31, and OSIRIS-REx will remain in orbit until mid-February 2019, when it exits to initiate another series of flybys for the next survey phase. During the first orbital phase, the spacecraft will orbit the asteroid at a range of 0.9 miles (1.4 km) to 1.24 miles (2.0 km) from the center of Bennu — setting new records for the smallest body ever orbited by a spacecraft and the closest orbit of a planetary body by any spacecraft.

    Goddard provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space Systems in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the agency’s New Frontiers Program for the Science Mission Directorate in Washington.

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