Terra has 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 have a 10:15 AM MLT crossing, and continue to drift to earlier MLT. At this time, we will also lower our orbit altitude to 694 km. After constellation exit, ASTER science observations will continue in concert with the changing MLT. The major effect will be that the ASTER 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 ASTER single pixel footprint size will decrease about 1% with the lower orbit altitude. We do not expect these orbit changes to have significant impacts to ASTER data quality. For more information, click on the link to Terra website.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an imaging instrument onboard Terra, the flagship satellite of NASA's Earth Observing System (EOS) launched in December 1999. ASTER is a cooperative effort between NASA, Japan's Ministry of Economy, Trade and Industry (METI), and Japan Space Systems (J-spacesystems). ASTER data are used to create detailed maps of land surface temperature, reflectance, and elevation. The coordinated system of EOS satellites, including Terra, is a major component of NASA's Science Mission Directorate and the Earth Science Division. The goal of NASA Earth Science is to develop a scientific understanding of the Earth as an integrated system, its response to change, and to better predict variability and trends in climate, weather, and natural hazards.