[Source: NASA Science Missions Home Page, http://nasascience.nasa.gov/missions/cloudsat
CloudSat uses advanced radar to "slice" through clouds to see their vertical structure, providing a ... completely new observational capability from space. Earlier satellites could only image the uppermost layers of clouds. CloudSat is among the first satellites to study clouds on a global basis. It will look at their structure, composition and effects. This is a cooperative mission with Canada. CloudSat measurements have applications in air quality, weather models, water management, aviation safety, and disaster management.
The key observations are the vertical profiles of cloud liquid water and ice water contents and related cloud physical and radiative properties. The spacecraft payload consists of a millimeter-wave radar. CloudSat will fly in tight formation with the CALIPSO satellite carrying a backscattering lidar, and these two satellites will follow behind the Aqua satellite in a somewhat looser formation. The combination of data from the CloudSat radar with coincident measurements from CALIPSO and Aqua provides a rich source of information that can be used to assess the role of clouds in both weather and climate.
CloudSat was launched on 2006-04-28 from Vandenberg AFB, California