Oct 21, 2019
This week, OSIRIS-REx continued Reconnaissance A phase operations and completed a high pass over candidate sample site Osprey.
On October 11, an unexpected DSN outage prevented critical optical navigation images from being downlinked from the spacecraft as scheduled. These navigation images were needed to support the final trajectory update for the October 12 Osprey pass. (Images of the asteroid are used to identify known features and update the trajectory of the spacecraft.) The team ended up receiving the images from the spacecraft early on October 12. They then processed them, updated the trajectory, built a new ephemeris, and uplinked that ephemeris to the spacecraft all in a four-hour timespan. These activities – known colloquially within the team as a “late update” – usually take 24 hours, a period already remarkably short by spacecraft operations standards. Since the spacecraft’s pointing is relative to its sense of “down” (or nadir), the new ephemeris served to correct the pointing to the Osprey site, which otherwise would have been off due to differences between the predicted and realized trajectories following the most recent maneuver (M4R).
The spacecraft executed navigation maneuver M6R on October 15, which placed it en route for the third flyby of the Reconnaissance A mission phase. The planned observations for site Kingfisher took place on October 19.