Terra and Aqua both recently completed a series of yaw maneuvers to cover a broad (roughly from -20 to -55 degrees) solar azimuth angle range to help MCST extend the characterization of the solar diffuser used for RSB calibration.

For Terra:

12 total yaw maneuvers at 2.5-degree spacing from -7.5 to 20 degrees

November 12^th -15^th, 2024 (3 per day)

For Aqua:

24 total yaw maneuvers at 3.0-degree spacing from -6.0 to 28 degrees

July 31^st, August 1^st, August 7^th, August 8^th, 2024 (6 per day)

Detailed yaw maneuver timing can be found in the MODIS Event Archive. 

Background: Yaw maneuvers were performed early in the mission to properly characterize the MODIS solar diffuser (SD) and solar diffuser screen (SDS). The measured yaw angles were chosen based on the expected solar azimuth angles that the MODIS SD would measure throughout the mission. Between early mission yaw maneuvers and pre-launch testing measurements, the SD and SDS were characterized for solar azimuth angles ranging from -16° to -33°. The drifting orbits of the spacecraft lead to a change in the observed solar azimuth angles which have already exceeded the early mission characterization range and will continue to drift. The 2024 yaw maneuver data are currently being analyzed to characterize the changes in SD illumination that will occur over the next two years (through mid-2026). The analysis results will help MCST continue RSB calibration using the SD.