Jun 17, 2019

OSIRIS-REx has successfully completed its Detailed Survey phase and transitioned into a new record-setting orbit around Bennu!

Last week the OSIRIS-REx navigation team performed three maneuvers using the spacecraft’s attitude control thrusters to place the spacecraft into orbit around Bennu for the second time. The first two maneuvers, on June 8 and 10, were staging burns that moved the spacecraft into position for the third burn on June 12, which ultimately placed OSIRIS-REx into orbit. These maneuvers imparted a velocity change (delta-v) of 8, 6, and 7 cm/sec, respectively. Throughout the Orbital B phase, slow changes in the spacecraft’s orbit will require correction maneuvers approximately every three weeks. The spacecraft’s circular orbit period around Bennu is 22 hours, with a velocity of 7 centimeters per second, which allows for the mission’s science measurements to be observed from a uniform altitude.

June 12 marked the beginning of the mission’s Orbital B phase, and the spacecraft began its new orbit approximately 680 meters above Bennu’s surface. This orbit breaks the record that OSIRIS-REx set during its Orbital A phase for the closest a spacecraft has ever orbited a small planetary body, which was as close as 1.3 km above the asteroid’s surface. The first two weeks of Orbital B will focus on investigating the causes of Bennu’s particle ejection events by taking frequent images of the asteroid’s horizon. The remaining five weeks of Orbital B will focus on mapping the asteroid from a close range.

With the conclusion of the Detailed Survey: Equatorial Stations phase on June 7, the team completed the mission’s main global survey effort. Here are the highlights from both Detailed Survey: Baseball Diamond and Detailed Survey: Equatorial Stations phases (Feb 22 – Jun 7):

• 14 Flyovers
• 18 Observation Stations
• 2,616 NavCam Images
• 19,660 OCAMS Images
• 2,286 OTES Data Acquisitions
• 179 OVIRS Science Acquisitions
• 19 OLA Scans
• 333,591 Total Spacecraft and Payload Commands