Oct 12, 2020
This week, OSIRIS-REx continued preparations for the Touch-And-Go (TAG) sample collection event scheduled for Oct. 20. On Oct. 3, the spacecraft performed a Sample Mass Measurement (SMM) bake-out activity. This bake-out exposes the Sample Return Capsule (SRC) to the sun and rids it of any accumulated condensation in normally shaded areas. The release of this condensation imparts a small force on the spacecraft that can corrupt the measurement of the sample during the actual SMM, so the bake-out is an attempt to “clean up” usually shady regions of the SRC before the SMM activity.
The spacecraft performed its first SMM maneuver on Oct. 10. This spin maneuver was performed with an empty collector head. After the TAG event, the spacecraft will perform a second SMM with a full collector head. The team then calculates the difference in the moment of inertia between the two spins to determine the mass of the sample.
To execute each SMM, the spacecraft extends its sampling arm and engages its reaction wheels to reach and maintain a steady spin.