Inside the mobile service tower on NASA's Space Launch Complex 2 at Vandenberg Air Force Base, the protective cover has been removed from the CALIPSO spacecraft in preparation for encapsulation and launch. Beneath CALIPSO, CloudSat is enclosed within the dual payload attach fitting. CALIPSO stands for Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation. It will fly in combination with the CloudSat satellite to provide never-before-seen 3-D perspectives of how clouds and aerosols form, evolve, and affect weather and climate. CALIPSO and CloudSat will join three other satellites in orbit to enhance understanding of climate systems. The spacecraft is scheduled to launch April 21 aboard a Boeing Delta II rocket.