Update: After investigation and monitoring of platform battery status, the Terra Flight Operations Team (FOT) determined that there was sufficient power to resume imaging with ASTER’s Visible and Near Infrared (VNIR) instrument. The FOT will continue to monitor the power usage, but as a result, ASTER once again began collecting VNIR data on January 17, 2025. Note that there is a data gap in ASTER acquisitions from November 28, 2024, through January 16, 2025.
On March 3, 2025, NASA's Land Processes Distributed Active Archive Center (LP DAAC) released ASTER VNIR-only data from January 17, 2025 – Present.
On November 28, 2024, at 14:20 UTC, one of Terra's power-transmitting shunt units failed. As a result, there was insufficient total power to maintain functionality of all the instruments. A response team reviewed Terra’s status and discussed potential impacts and options. Consequently, the team changed the battery charge rate and reduced spacecraft power demands by placing the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument into Safe Mode. This decision was made based on earlier discussions between the ASTER Science Team, Terra Project Scientist, Terra Instrument Teams, and the Flight Operations Team (influenced by the fact that ASTER is the largest power user on Terra). As a result, ASTER data are not currently being collected.
All other instruments, including Terra Moderate Resolution Imaging Spectroradiometer (MODIS), have continued data acquisitions without interruption. The engineering team will continue to closely monitor Terra’s power output. Discussions are continuing on how ASTER can resume limited operations in the near future. Stay tuned for future updates on ASTER’s status.
The following ASTER datasets have been impacted by this power issue.
- ASTER Level 1A Reconstructed Unprocessed Instrument Data (AST_L1A)
- ASTER Expedited Level 1A Reconstructed Unprocessed Instrument Data (AST_L1AE)
- ASTER Level 1B Registered Radiance at the Sensor (AST_L1B)
- ASTER Expedited Level 1B Registered Radiance at the Sensor (AST_L1BE)
- ASTER Level 1 Precision Terrain Corrected Registered At-Sensor Radiance (AST_L1T v3 & AST_L1T v3.1)
- ASTER L2 Surface Emissivity (AST_05)
- ASTER L2 Surface Reflectance VNIR and SWIR (AST_07)
- ASTER L2 Surface Reflectance SWIR Crosstalk-Corrected (AST_07XT)
- ASTER L2 Surface Kinetic Temperature (AST_08)
- ASTER L2 Surface Radiance VNIR and SWIR (AST_09)
- ASTER L2 Surface Radiance SWIR Crosstalk-Corrected (AST_09XT)
- ASTER L2 Surface Radiance TIR (AST_09T)
- ASTER Digital Elevation Model (AST14DEM)
- ASTER Digital Elevation Model and Orthorectified Registered Radiance at the Sensor (AST14DMO)
- ASTER Orthorectified Registered Radiance at the Sensor (AST14OTH)
Thank you for your patience during this Safe Mode event. We offer our sincerest apologies for any inconvenience this may cause.
Please contact LP DAAC User Services with any questions or concerns.