Double Delta Satellite mission

by Chris Bergin

Two new earth-observation satellites are set to launch from Vandenburg Air Force Base, California with a nearly instantaneous launch window opening at 3:01:05 AM (PT) October 26th.

The CloudSat and CALIPSO satellites are to be launched as a pair using a Delta II 7420-10C rocket equipped with four strap-on boosters and a Dual Payload Attach Fitting.

A successful launch of the satellite pair will form an “A Train” constellation of five satellites that will provide a unique three dimensional representation of atmospheric clouds and aerosols that will be used to improve weather and climate change predictions.

CALIPSO will fly in a 3000KM (1864 mile) long orbital formation with four other earth observation satellites – beginning with NASA’s AQUA satellite, followed by CloudSat and CALIPSO.

Next in line is France’s PARASOL satellite, and the orbital trains’ caboose will be NASA’s AURA instrument. It will take approximately 30 to 45 days to maneuver the satellites into a 705 KM (438 mile) high formation that will allow AQUA, CloudSat and CALYPSO to view the same ground track while making observations.

The constellation is named after an old jazz tune “Take the A-train”, made popular by Duke Ellington, because AQUA forms the beginning of the constellation, and AURO forms the end of the afternoon constellation.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite was jointly developed by NASA and the French Space Agency, Centre National d’Etudes Spatiales. CALIPSO is equipped with a lidar (light detection and ranging) sensor system that uses reflected polarized laser light to differentiate between spherical water droplets and ice crystals, key to providing the first global survey of cloud and aerosol profiles. NASA’s Langley Research Center developed the lidar sensor system in partnership with Ball Aerospace and Technologies Corporation, located in Boulder, Colorado.

CALIPSO is a satellite that weighs 587 Kg (1,294 pounds) fully fueled at launch and generates about 550 watts of electrical power with it’s 32 foot long solar panels. The primary instrument is a three-channel polarization lidar that will provide high-resolution vertical profiles of aerosols and clouds using a one meter wide telescope.

A three channel Imaging Infrared Radiometer is used to optimize the gathering of joint lidar-radiometer cirrus cloud emission and particle size information. A wide-field camera, a modified Ball Aerospace and Technologies Corp CT-633 star tracker, is used to determine cloud uniformity during daylight operations.

CALIPSO will help provide the first statistics describing the vertical structure of clouds, global vertical distribution of aerosols and aerosol types, and the first indirect (but validated) estimates of how much clouds and aerosols contribute to the vertical distribution of atmospheric warming. CALIPSO will also help determine how often very thin, invisible cirrus clouds form and whether these clouds change with the seasons.

The $275 M CALIPSO mission was developed under NASA’s Earth System Science Pathfinder Program and is expected to last approximately 36 months.

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