The thermal infrared capabilities of an imager on NASA’s Terra satellite have been shut off and will no longer collect data, more than 25 years after the instrument captured its first image of Earth from space. This is the latest effort to prioritize power on Terra for its remaining instruments. Terra, which had a design life of six years when launched, has long outperformed its mission life.
The Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER, is one of five instruments aboard Terra, which launched in December 1999. The ASTER instrument was created as part of a cooperative effort between NASA and Japan’s Ministry of Economy, Trade and Industry.
The ASTER Thermal Infrared (TIR) subsystem was turned off Jan. 16, due to power limitations on the spacecraft. The ASTER TIR thermal control system was powered off on Feb. 6, to provide necessary power to continue to operate the remaining Terra instruments. Turning off the TIR thermal control system means that the ASTER TIR subsystem will no longer be recoverable even if power margins improve. However, with the power margin provided by turning off the TIR thermal control system, the ASTER Visible and Near Infrared operations were able to resume on Feb. 9.
The instrument has been called the “zoom lens” of Terra, as it was designed to collect high resolution images in 14 wavelengths of light, ranging from visible to infrared. Data from ASTER has been used to map Earth’s land cover, surface temperatures, reflectivity, elevation, volcanoes, and more.
Its stereo camera allowed researchers to create the ASTER Digital Elevation Model, a map of Earth’s topography with spatial resolution at the scale of a baseball infield. A global map of how efficiently a surface emits thermal radiation, or emissivity, was also built on ASTER data.
The Clouds and the Earth’s Radiant Energy System (CERES) aft instrument was turned off Jan. 10, 2025, and CSA’s (Canadian Space Agency) Measurement of Pollution in the Troposphere Instrument was turned off April 9, 2025, to manage power limitations on the spacecraft. Terra’s Moderate Resolution Imaging Spectroradiometer, Multi-angle Imaging Spectroradiometer, and CERES-Fore continue to collect science data.
By Kate Ramsayer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
