CALIPSO, a lidar satellite that advanced the world’s understanding of climate, weather, and air quality, ended its scientific mission on Aug. 1, 2023.
Across 17 years of operation, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation recorded more than 10 billion lidar measurements and informed thousands of scientific reports. CALIPSO was launched jointly by NASA and the France's Centre National d’Etudes Spatiales/CNES and in tandem with the cloud-profiling radar system on the CloudSat satellite.
“We had to build, for the first time, a sophisticated lidar capable of operating in space,” said Chip Trepte, NASA's project scientist for CALIPSO. “Then we intended to fly that satellite in close formation to match the CALIPSO lidar profile measurements with the radar profile measurements from CloudSat.”
Lidar and radar are considered “active” sensors because they direct beams of energy at the Earth — laser light in the case of CALIPSO and radio waves in the case of CloudSat — and then measure how the beams reflect off the clouds and aerosols in the atmosphere. Other orbiting science instruments use “passive” sensors that measure reflected sunlight or radiation emitted from the Earth or clouds. The combined data from CALIPSO and CloudSat provided new insights into cloud structures and aerosol layers.
Read more at NASA