NASA Launches Satellites for Weather, Climate, Air Quality Studies
28 Apr 2006
Two 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 at 3:02 a.m. PDT 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 Dr. 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."
"With the successful launch of CloudSat and Calipso we take a giant step forward in our ability to study the global atmosphere," said Calipso Principal Investigator Dr. David Winker of NASA's Langley Research Center, Hampton, Va. "In the years to come, we expect these missions to spark many new insights into the workings of Earth's climate and improve our abilities to forecast weather and predict climate change."
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 rocket's 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, 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.
For more information about CloudSat and Calipso, visit: