CALIPSO is a collaboration between NASA Langley Research CENTER (LaRC), the French space agency CNES, Hampton University, the Institut Pierre Simon Laplace (IPSL) and Ball Aerospace & Technologies Corp. The primary roles and contributions of these partners can be found at http://www-calipso.larc.nasa.gov/ . This mission is part of NASA. As part of NASA's Earth System Enterprise, this is a series of missions designed to examine critical issues in Earth system science.