本日のGPM 2014.03.22

■GPM Update Fri, 2014-03-20 9:41 a.m. EDT [NASA]

On March 17, the team executed GPM's first scheduled yaw turn to turn the orientation of the spacecraft 180 degrees. Yaw is the left/right orientation in the horizontal plane of the spacecraft's motion. The spacecraft is now "flying backwards." Yaw maneuvers will be performed approximately every 40 days for spacecraft thermal control, as the angle between the spacecraft's orbit and the sun changes. This keeps the side of the spacecraft that is designed to remain cold from overheating. Yaw maneuvers are performed primarily using the spacecraft's reaction wheels.

GPM主衛星は太陽光入射からなる熱制御のため、これまで進行方向前方を向いていた面を後方に向けるようにヨー軸の姿勢制御を行ったそうです。これは40日毎に行われると書かれていますね。