Aug 17, 2020
On Aug. 11, the OSIRIS-REx mission completed its second successful sample collection rehearsal, known as Matchpoint rehearsal. This was the mission’s final practice run before touching down on asteroid Bennu’s surface in October.
During the rehearsal, the spacecraft departed its 1-km safe-home orbit, and then performed the Checkpoint maneuver at an approximate altitude of 125 meters above Bennu’s surface. From there, the spacecraft continued to descend for another eight minutes to execute the Matchpoint burn approximately 54 meters above the asteroid. This was the first time the spacecraft executed the Matchpoint maneuver to then fly in tandem with Bennu’s rotation. After descending on this new trajectory for another three minutes, the spacecraft reached an altitude of approximately 40 meters – the closest the spacecraft has ever been to Bennu – and then performed a back-away burn to complete the rehearsal.
This rehearsal was also the first time that the spacecraft’s on-board hazard map was employed. The hazard map delineates small areas of the sample collection site that could potentially harm the spacecraft due to large, nearby rocks. A post-rehearsal analysis confirmed that the spacecraft’s trajectory and predicted touchdown would have successfully avoided surface hazards and allowed for a safe touchdown on sample site Nightingale.
As part of rehearsal activities, the spacecraft also deployed the TAGSAM arm from its folded, parked position out to the sample collection configuration. Some of the spacecraft’s instruments also collected science and navigation images and made spectrometry observations of the sample site, as will occur during the actual sample collection event.