Upcoming Terra Constellation Exit
On February 27, 2020, Terra completed all mission maneuvers related to maintaining a 10:30 mean local time (MLT) equator crossing and 705 km orbit altitude. Terra will begin drifting to an earlier MLT around April 2021. In October 2022, Terra will reach and exceed a 10:15 AM MLT crossing corresponding to a constellation exit with lower orbit altitude (694 km). MLT will continue to drift after this, reaching 9:00 AM around December 2025. 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.