Upcoming Aqua Constellation Exit
On March 18, 2021, Aqua completed all mission maneuvers related to maintaining a 1:30 mean local time (MLT) equator crossing and 705 km orbit altitude. In July 2021, Aqua began drifting to a later MLT. In January 2022, Aqua will begin its constellation exit, by stopping all maneuvers except collision avoidance maneuvers, and will reach and exceed a 1:45 AM MLT crossing in February 2023. MLT will continue to drift after this, reaching 3:50 PM around August 2026. After constellation exit, MODIS science observations will continue in concert with the changing MLT. The major effect will be that the MODIS surface sampling pattern will no longer be repeating every 16 days. However, sample locations will be reported with the data in the same format as current data. The MODIS single pixel footprint size will decrease slightly with lower orbit altitude. We do not expect these orbit changes to have significant impacts to MODIS retrieval quality.