TAGSAM Sample Collector

The Touch-And-Go Sample Acquisition Mechanism (TAGSAM) is an elegantly simple sampler head with an articulated arm. It is designed to collect a sample from the surface of Bennu.

Once the sampler head makes contact with the surface of Bennu, a burst of pure nitrogen gas will push surface regolith into the sampler's chamber. Surface contact pads on the exterior of TAGSAM will also collect fine-grained material as the sample collector touches down on the asteroid.

This method was chosen since it eliminates the risks associated with landing on the asteroid. There are three separate bottles of nitrogen gas, which allow up to three sampling attempts. Although TAGSAM is a new technology, vacuum and micro-gravity tests of the TAGSAM sampler head have proven its ability to collect more than the required 60 grams of sample

OTES

The OSIRIS-REx Thermal Emission Spectrometer (OTES) provides mineral and temperature information by collecting infrared (from ~5 to 50 microns) spectral data from Bennu. In the infrared, most minerals have unique spectral signatures that are like fingerprints. By understanding which minerals correspond to specific spectral signatures, scientists can identify the minerals that are present on the surface of Bennu. Additionally, the emitted heat energy (temperature) at these wavelengths can tell the science team about physical properties of the surface, such as the average particle size. OTES is also used to measure the total thermal emission from Bennu. Thermal data from OTES will allow scientists to identify the mineral composition and temperature distribution of Bennu for global maps and local candidate sample-site areas.

Detailed Specifications and Instrument Operations

OTES's wavelength range, resolution, and radiometric performance are sufficient to resolve and identify the key vibrational absorption features of silicate, carbonate, sulfate, phosphate, oxide, and hydroxide minerals. While operating, OTES collects a single interferogram every 2 seconds. The motion of the spacecraft allows OTES to scan the surface of Bennu, gathering data that will be used to construct maps. No on-board data processing or compression is performed.

The OTES team is led by Philip Christensen (Instrument Scientist, ASU), Victoria Hamilton (Deputy Instrument Scientist, SwRI), and Greg Mehall (Instrument Manager, ASU).

OVIRS

The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) measures visible and infrared light from Bennu. OVIRS is sensitive from blue through near-infrared wavelengths, spanning 0.4 to 4.3 microns. OVIRS will split the light received from Bennu into its component wavelengths, much like a prism can split sunlight into a visible rainbow. Since different chemicals have unique spectral signatures, they can be identified this way. OVIRS will provide spectral maps that identify mineral and organic material globally and of candidate sample sites. It will also gather local spectral information of candidate sample sites.

Detailed Specifications and Instrument Operations

The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) is a point spectrometer that provides mineral and organic spectral maps and local spectral information of candidate sample sites. It also provides full asteroid spectral data, global spectral maps (20-m resolution), and spectra of the sample site (0.08–2-m resolution).

OVIRS spectra will identify volatile and organic-rich regions on Bennu. These data, in concert with OTES spectra, will guide sample-site selection. OVIRS spectral ranges and resolution will allow the creation of surface maps of mineralogical and molecular components including carbonates, silicates, sulfates, oxides, adsorbed water, and a wide range of organic molecules.

OVIRS can observe the entire surface of Bennu over a wide range of phase angles (the angle between OVIRS and the sun) of 3° or less during the asteroid survey. Spectral data obtained at different local times and phase angles, mostly during Detailed Survey will be combined with surface temperatures measured by OTES and the longer wavelength OVIRS channels to determine the actual albedo change from the OVIRS spectra; observations at high phase angles will emphasize the thermal contribution.

The OVIRS design is inexpensive, compact, has no moving parts, and allows for straightforward operation. The camera operates in a scanning mode in which the rotational motion of the asteroid is combined with a scanning motion of the spacecraft to sample a region of interest. Typical observations will provide global sampling of the surface with a spatial resolution of 20 meters at a fixed phase angle for measurements from 5-km altitude. At low altitudes, OVIRS obtains high spatial resolution measurements (~2m).

Two types of contamination could affect OVIRS' measurements. Molecular contaminants, and water in particular, can condense on the cold focal plane. To mitigate this, a nitrogen purge is used until launch. After launch, decontamination heaters bake off any remaining water or molecular contaminant before cooling. After this process, any residual signals from contamination can be calibrated out of OVIRS' data.

The OVIRS team is led by Dennis Reuter (Instrument Scientist, GSFC), Amy Simon (Deputy Instrument Scientist, GSFC), and Jason Hair (Instrument Manager, GSFC).

REXIS

The Regolith X-ray Imaging Spectrometer (REXIS) is a student experiment that will determine which elements are present, and how abundant they are, on the surface of Bennu. This capability will complement the onboard mineral mapping provided by OVIRS and OTES. REXIS takes advantage of the fact that solar X-rays and the solar wind interact with the regolith on Bennu's surface. Atoms on Bennu will absorb these X-rays, causing them to become unstable and emit their own x-rays in turn. The re-emitted X-rays have an energy that is characteristic of the atom from which it came. This process - called fluorescence - allows for mapping of the different elements present on Bennu's surface.

Detailed Specifications and Instrument Operations

REXIS will provide an elemental abundance map of Bennu, which will complement the onboard mineral mapping. Using X-ray spectrometry, REXIS will perform spatially resolved elemental abundance mapping. This furthers the understanding of the sample site composition.

REXIS is a coded aperture soft X-ray (0.3–7.5 keV) telescope that images X-ray fluorescence line emission. Solar X-rays and the solar wind interact with the regolith of Bennu and produce this emission. Imaging is achieved by correlating the detected X-ray image with a 64 x 64 element random mask (1.536 mm pixels). REXIS forms images with 21-arcminute resolution (4.3 m spatial resolution at a distance of 700 m). REXIS will store each X-ray event in order to maximize the data storage usage and to minimize the risk. The pixels will be addressed in 64 x 64 bins and the 0.3–7.5 keV range will be covered by 5 broad bands and 11 narrow line bands. A 24-sec resolution time tag will be interleaved with the event data to account for Bennu rotation. Images will be reconstructed on the ground after downlink of the event list.

Images are formed simultaneously in 16 energy bands centered on the dominant lines of abundant surface elements from O-K (0.5 keV) to Fe-Kß (7 keV) as well the representative continuum. For 34 days during orbital phase B, 700 m from the surface of Bennu, a total of at least 133 events/asteroid pixel/energy band are expected under 2 keV; enough to obtain significant constraints on element abundances at scales larger than 10 m.

After a competitive selection process REXIS was chosen as a Student Collaboration Experiment for OSIRIS-REx. Students at Harvard and MIT will perform data analysis as part of their coursework and through MIT's Undergraduate Research Opportunities Program. Over 15 semesters, more than 100 undergraduate, and more than 10 graduate students will participate in the REXIS project. At MIT, faculty leadership is provided by Professor David Miller, Professor Richard Binzel, and Professor Sara Seager. At Harvard, faculty leadership is provided by Professor Josh Grindlay.

OCAMS: PolyCam

PolyCam, an 8-inch telescope, is the first to "see" the asteroid from 2 million km away. PolyCam can detect Bennu at long-range; its larger plate scale extends its sensitivity by exposing for longer periods. Once the spacecraft is closer, it will image Bennu at very high resolutions.

Detailed Specifications and Instrument Operations

The OSIRIS-REx Camera Suite (OCAMS) consists of three cameras: PolyCam, MapCam, and SamCam. These cameras will "see" asteroid Bennu as the spacecraft first approaches it. OCAMS will then provide global image mapping and sample site imaging and characterization. Finally, OCAMS will record the entire sampling event during the touch-and-go (TAG) maneuver. If any of these cameras should fail, the other two imagers can step in.

A single Camera Control Module (CCM) controls OCAMS operation during the mission. Commands are submitted and stored as scheduled sequences. The CCM operates the filter wheel, cameras, focusing mechanism, heaters, and the lamps of an in-flight calibration tracing system.

OCAMS is the latest in a long line of space-qualified cameras built by the University of Arizona. Past cameras include Imager for Mars Pathfinder (IMP), Huygens Descent Imager and Spectral Radiometer (DISR), Phoenix Surface Stereo Imager (SSI), and Phoenix Robotic Arm Camera (RAC).

The OCAMS team is led by Bashar Rizk (Instrument Scientist, UA), Christian d'Aubigny (Deputy Instrument Scientist, UA), and Chuck Fellows (Instrument Manager, UA).

OCAMS: MapCam

MapCam is designed to search for satellites and outgassing plumes on Bennu. It maps the asteroid in 4 different colors at a 1-meter resolution, which will provide spectral information about Bennu as well as high-resolution imaging of the sample site. It can also perform imaging to verify the spacecraft's position and velocity relative to Bennu using optical navigation techniques.

Detailed Specifications and Instrument Operations

The OSIRIS-REx Camera Suite (OCAMS) consists of three cameras: PolyCam, MapCam, and SamCam. These cameras will "see" asteroid Bennu as the spacecraft first approaches it. OCAMS will then provide global image mapping and sample site imaging and characterization. Finally, OCAMS will record the entire sampling event during the touch-and-go (TAG) maneuver. If any of these cameras should fail, the other two imagers can step in.

A single Camera Control Module (CCM) controls OCAMS operation during the mission. Commands are submitted and stored as scheduled sequences. The CCM operates the filter wheel, cameras, focusing mechanism, heaters, and the lamps of an in-flight calibration tracing system.

OCAMS is the latest in a long line of space-qualified cameras built by the University of Arizona. Past cameras include Imager for Mars Pathfinder (IMP), Huygens Descent Imager and Spectral Radiometer (DISR), Phoenix Surface Stereo Imager (SSI), and Phoenix Robotic Arm Camera (RAC).

The OCAMS team is led by Bashar Rizk (Instrument Scientist, UA), Christian d'Aubigny (Deputy Instrument Scientist, UA), and Chuck Fellows (Instrument Manager, UA).

OCAMS: SamCam

SamCam will document the sample acquisition event and TAG maneuver, imaging down to millimeter scales during the sample collection. Taking an image as fast as one every 1.6 seconds, SamCam will supply important information about the sampling event, allowing scientists and engineers to determine important physical characteristics of the surface.

Detailed Specifications and Instrument Operations

The OSIRIS-REx Camera Suite (OCAMS) consists of three cameras: PolyCam, MapCam, and SamCam. These cameras will "see" asteroid Bennu as the spacecraft first approaches it. OCAMS will then provide global image mapping and sample site imaging and characterization. Finally, OCAMS will record the entire sampling event during the touch-and-go (TAG) maneuver. If any of these cameras should fail, the other two imagers can step in.

A single Camera Control Module (CCM) controls OCAMS operation during the mission. Commands are submitted and stored as scheduled sequences. The CCM operates the filter wheel, cameras, focusing mechanism, heaters, and the lamps of an in-flight calibration tracing system.

OCAMS is the latest in a long line of space-qualified cameras built by the University of Arizona. Past cameras include Imager for Mars Pathfinder (IMP), Huygens Descent Imager and Spectral Radiometer (DISR), Phoenix Surface Stereo Imager (SSI), and Phoenix Robotic Arm Camera (RAC).

The OCAMS team is led by Bashar Rizk (Instrument Scientist, UA), Christian d'Aubigny (Deputy Instrument Scientist, UA), and Chuck Fellows (Instrument Manager, UA).

TAGCAMS: StowCam

StowCam is a Malin Space Science Systems ECAM-C50 5-megapixel color camera, and is capable of acquiring still images and high-definition video. It is part of a Touch-and-Go Camera System (TAGCAMS) which consists of two redundant Navigation Cameras, and the single StowCam.

SRC

The Sample Return Capsule (SRC) is designed to hold and return the sample of Bennu's regolith to Earth. It has a heritage design that is based on the SRC used by Stardust to successfully return tail material from Comet Wild 2 in 2006.

In 2023 the OSIRIS-REx SRC will return between 60 grams and 2 kilograms of sample from Bennu. It will enter the atmosphere at a nominal entry angle of -8.2° and a velocity of 12.2km/s. The capsule will spin at a rate of 13 RPM. Spinning provides stability during vacuum flight and through the upper atmosphere, where it undergoes maximum heating. The aeroshell thermal protection system removes over 99% of the kinetic energy of the vehicle, protecting the sample from aerodynamic heating and keeping the sample below 75°C — a requirement for maintaining its pristine condition.

Less than 2 minutes after peak heating, the SRC will free-fall through the atmosphere and the onboard avionics will initiate parachute deployment. A stabilizing drogue parachute deploys while 33km above the Earth. When it is 3km in altitude, the main parachute deploys. On September 24, 2023, the SRC will land within a 80 x 25 km area at the Utah Test and Training Range (UTTR). It takes 15 minutes for the SRC to land once it enters the Earth's atmosphere.

Upon atmospheric entry, the SRC will be tracked with UTTR radars to within ~10 m of the landing location. Once landed, crews will recover and transport the SRC to a staging area at UTTR. It is then prepared and transported to Johnson Space Center (JSC).

Air samples are taken at both landing site and the staging area to test for SRC outgassing. In addition, relevant soil samples will be taken from the landing site, as well as samples of any other materials the SRC may have come into contact with during landing and recovery.

The sample canister will be removed from the SRC and all hardware will be transported to the JSC Space Exposed Hardware cleanroom. Within 120 hours of landing, the sample canister will be opened in a curatorial facility at JSC. The science team and international cosmochemistry community will perform preliminary examination of the sample, followed by a detailed inventory in preparation for analysis.

OLA

The OSIRIS-REx Laser Altimeter (OLA) is a scanning LIDAR (Light Detection and Ranging). A LIDAR is similar to a RADAR, but uses light instead of radio waves to measure distance. OLA will emit laser pulses at the surface of Bennu, which will reflect back from the surface and return a portion of the laser pulse to the LIDAR detector. By carefully measuring the time difference between the outgoing pulse and the incoming pulse, the distance the spacecraft and the surface of Bennu can be computed using the speed of light. This allows OLA to provide high-resolution topographical information about Bennu during the mission. OLA will create global topographic maps of Bennu and local maps of candidate sample sites. OLA ranging measurements will also support other instruments and navigation and gravity analyses.

Detailed Specifications and Instrument Operations

OLA will scan the surface of Bennu at specific times in the mission to rapidly map out the entire surface of the asteroid. This will produce local and global topographic maps. OLA will enhance and refine gravitational studies of Bennu by developing a control network relative to the center of mass of Bennu.

OLA has a single common receiver and two complementary transmitter assemblies. OLA's high-energy laser transmitter will range and map from 1 to 7.5 km. The low-energy transmitter will range and image at smaller distances (500 m to 1 km). The pulse rate of these transmitters sets the data acquisition rate of OLA. OLA directs laser pulses onto a movable scanning mirror. This mirror is co-aligned with the field of view of the receiver telescope. This design limits the effects of background solar radiation. Each pulse provides target range, azimuth, elevation, received intensity and a time-tag.

A simple parameterized raster scanning pattern is used for all mission phases. In addition to its enhanced precision, after Orbital Phase B, OLA exceeds the coverage and data quality of previous asteroid missions, surpassing the Hayabusa mission coverage of Itokawa by a factor of 20, and the NEAR laser rangefinder results at 433 Eros by a factor of 2 after correcting for the significant difference in size between Eros and Bennu. OLA data will provide fundamental and unprecedented asteroid science on asteroid shape and topography. This will allow OLA to infer the surface processes that have shaped the evolution of Bennu and the source materials collected in the sample. OLA complements other instruments' measurements by setting precise range, scale and surface slope information.

OLA is a contributed instrument from the Canadian Space Agency. The OLA science team is an integrated Canada-US team led by Michael Daly (York University, OLA Instrument Scientist). Team members include Catherine Johnson (University of British Columbia, OLA Deputy Instrument Scientist) and Olivier Barnouin (Johns Hopkins University Applied Physics Laboratory, Altimetry Working Group Lead). Along with OLA, Canada is supporting members of the Mission Science Team including: Alan Hildebrand (University of Calgary), Ed Cloutis (University of Winnipeg), Rebecca Ghent (University of Toronto) and Kim Tait (Royal Ontario Museum).

TAGCAMS: NavCams

The NavCams, or Navigation Cameras, are part of the guidance, navigation, and control system on OSIRIS-REx. They are used for optical navigation of the spacecraft.

NavCam images will track star-fields and landmarks on Bennu to determine the spacecraft position during mission operations. Each NavCam is a Malin Space Science Systems ECAM-M50 5-megapixel monochrome camera, and is capable of acquiring still images and high-definition video. They are part of a Touch-and-Go Camera System (TAGCAMS) which consists of two redundant Navigation Cameras, and the single StowCam.

HGA

The High Gain Antenna (HGA) provides communication between the spacecraft and ground systems. The HGA will also be used for Doppler tracking and other radio science activities during the mission.