The CloudSat mission was selected under NASA's Earth System Science Pathfinder program (ESSP) in 1999.
Overseen by NASA's Science Mission Directorate, the Earth System Science Pathfinder Program sponsors missions designed to address unique, specific, highly focused scientific issues, and to provide measurements required to support Earth science research. (image at right of how CLOUDSAT satellite was launched, click image for detail, from Cloudsat site)
Missions selected in this program are small- to- medium-sized and are capable of being built, tested, and launched quickly.
They support a variety of scientific objectives related to Earth science, including studies of the atmosphere, oceans, land surface, polar ice regions, and solid Earth.
CloudSat's primary mission is scheduled to continue for 22 months after launch in 2006, in order to allow more than one seasonal cycle to be observed, although radar lifetime data indicates that the radar is expected to operate for three years with a 99 percent probability.