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Cloud Research Satellites Launched Aboard Delta II

By | May 1, 2006

      Two National Aeronautics and Space Administration (NASA) satellites were launched Friday from Vandenberg Air Force Base, Calif., on missions to reveal the inner secrets of clouds and aerosols, tiny particles suspended in the air.

      CloudSat and CALIPSO – Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations – thundered skyward Friday atop a Boeing Delta II rocket. The two satellites will eventually circle approximately 705 kilometers (438 miles) above Earth in a sun-synchronous polar orbit, which means they will always cross the equator at the same local time. Their technologies will enable scientists to study how clouds and aerosols form, evolve and interact.

      "Clouds are a critical but poorly understood element of our climate," said Graeme Stephens, CloudSat principal investigator and a professor at Colorado State University, Fort Collins, Colo. "They shape the energy distribution of our climate system and our planet’s massive water cycle, which delivers the freshwater we drink that sustains all life."

      Each spacecraft will transmit pulses of energy and measure the portion of the pulses scattered back to the satellite. CloudSat’s Cloud-Profiling Radar is more than 1,000 times more sensitive than typical weather radar. It can detect clouds and distinguish between cloud particles and precipitation. CALIPSO’s polarization lidar can detect aerosol particles and distinguish between aerosol and cloud particles. Lidar, similar in principle to radar, uses reflected light to determine the characteristics of the target area.

      Sixty-two minutes after liftoff, CALIPSO separated from the Delta II second stage. CloudSat followed 35 minutes later. Ground controllers successfully acquired signals from both spacecraft, and initial telemetry reports show both to be in excellent health. Over the next six weeks, system and instrument checks will be performed, and the satellites will be inserted into their final orbits.

      The satellites will fly in formation as members of NASA’s "A-Train" constellation, which also includes NASA’s Aqua and Aura satellites and a French satellite known as Parasol, which stands for Polarization and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar. The satellite data will be more useful when combined, providing insights into the global distribution and evolution of clouds to improve weather forecasting and climate prediction.

      CloudSat is managed by NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif. JPL also developed the radar instrument with hardware contributions from the Canadian Space Agency. JPL is managed for NASA by the California Institute of Technology. Colorado State University provides scientific leadership and science data processing and distribution. Ball Aerospace and Technologies Corp., Boulder, Colo., designed and built the spacecraft. The Air Force and Department of Energy contributed resources. U.S. and international universities and research centers support the mission science team.

      CALIPSO is a collaboration between NASA and France’s Centre National d’Etudes Spatiales. Langley is leading the CALIPSO mission and providing overall project management, systems engineering, and payload mission operations. NASA’s Goddard Space Flight Center, Greenbelt, Md., provides support for system engineering, project and program management. The French Space Agency is providing a Proteus spacecraft developed by Alcatel Space, a radiometer instrument, and spacecraft mission operations. Hampton University, Hampton, Va., is providing scientific contributions and managing the outreach program. Ball Aerospace developed the lidar and on-board visible camera.

      NASA’s Launch Services Program at Kennedy Space Center, Fla., procured the mission’s launch and provided the management for the mission’s launch service.

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