Dec 17, 2018
This month, the spacecraft has been progressing through the maneuvers of the mission’s Preliminary Survey phase. Starting on Dec 3, the spacecraft executed seven maneuvers (M1P – M7P) to make three passes over Bennu’s north pole and one each over its equator and south pole. Each flyby brought OSIRIS-REx within seven km from Bennu’s surface.
The M2P and M3P burns, executed on Dec. 5 and 7 respectively, for the first time completely reversed the direction of the spacecraft’s motion in order to initiate further flybys of Bennu’s north pole. These maneuvers highlight the unique character of the complex trajectories required for this mission’s asteroid proximity operations, which can be described as the spacecraft “formation flying” with Bennu.
During these Bennu passes, the spacecraft’s MapCam camera, OTES and OVIRS spectrometers, and OLA laser altimeter have been taking close observations of Bennu’s surface. This is the first time that the spacecraft has been close enough to employ OLA, which takes ranging measurements of the asteroid. These observations will be used to make 3D topographic maps of the asteroid.