Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) was launched on April 28, 2006 to study the roles of clouds and aerosols of climate and weather.  It flew in the international "A-Train" constellation for coincident Earth observations until September 13, 2018 when CALIPSO began lowering its orbit from 705 km to 688 km (428 miles) above the Earth to resume formation flying with CloudSatas part of the “C-Train”.  The CALIPSO satellite comprises three instruments, the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP Lidar), the Imaging Infrared Radiometer (IIR), and the Wide Field Camera (WFC).  CALIPSO is a partnership between NASA and the French Space Agency, CNES.

NASA and CNES agreed to end the CALIPSO science mission on August 1, 2023. This mission has been highly successful: designed for a lifetime of 3 years, CALIPSO delivered unprecedented measurements of the vertical structure of the Earth’s atmosphere for 17 years. Fuel reserves are now exhausted, and in its decaying orbit the satellite can no longer generate sufficient power to operate the science instruments. Both agencies thank the international data user community for their on-going interest and support. Over the next two years (through September 2025), the project will continue to refine and document its extensive data products catalog and will notify the community as these products are updated.