The CALIPSO-CloudSat Validation Experiment (CC-VEx) was conducted between July 24 and August 14, 2006 and was designed to provide coincident observations of cloud and aerosol (small particles) layers needed to support calibration and validation studies for two new satellite missions: CALIPSO and CloudSat. These missions provide valuable new information on vertical structure and properties of aerosols and clouds needed to improve our understanding of climate, weather, and air quality. They were launched together on a Delta II launch vehicle on April 28, 2006 and placed in formation with three other earth observing satellites into what is commonly known as the “ A-Train” satellite constellation. CALIPSO is a joint mission between NASA and the French space agency, CNES, and its payload consists of an innovative two-wavelength polarization-sensitive lidar, an infrared imaging radiometer, and a wide field-of-view camera. CloudSat is a partnership between NASA, the Canadian space agency, and the United States Air Force, and its payload consists ofa state-of-the-art cloud profiling radar operating at 94 GHz.