CALIPSO was a joint NASA (US) and CNES (France) environmental satellite, built in the Cannes Mandelieu Space Center, which was launched atop a Delta II rocket on April 28, 2006. Its name stands for Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations. CALIPSO launched alongside CloudSat.

Passive and active remote sensing instruments on board the CALIPSO satellite monitored aerosols and clouds 24 hours a day. CALIPSO was part of the "C-Train" alongside CloudSat, orbiting on a similar track to the "A-Train." The mission ended on August 1, 2023 after over 17 years. Final passivation occurred on December 15, 2023.^[1]

Three instruments:

• Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) - a lidar that provided high-resolution vertical profiles of aerosols and clouds.
• Wide Field Camera (WFC) - a modified version of the commercial off-the-shelf Ball Aerospace CT-633 star tracker camera. It was selected to match band 1 of the MODIS instrument on the Aqua satellite.
• Imaging Infrared Radiometer (IIR) - used to detect cirrus cloud emissivity and particle size. The CALIOP laser beam is aligned with the center of the IIR image to optimize joint CALIOP/IIR observations.

In February 2009, CALIPSO switched over to the redundant laser as scheduled. The primary laser achieved its mission goal of three years of successful operation, and the redundant laser has been performing beyond expectations.

The CALIPSO mission was granted extended mission status in June 2009. CALIPSO moved to the C-Train in 2020. The mission ended on August 1, 2023 due to lack of propellant.^[2]

• A-train (satellite constellation)
• Earth Observing System
• List of spaceflights (2006)

• CALIPSO Outreach
• CALIPSO and the A Train
• The CALIPSO page at NASA
• The CALIPSO page at French National Centre for Space Studies (CNES)
• CALIPSO Mission Profile by NASA's Solar System Exploration
• CALIPSO results in five to ten years
• CALIPSO specs at NASA
• (https://www.nasa.gov/feature/first-long-duration-lidar-satellite-mission-calipso-ends)