CLAMS is the Chesapeake Lighthouse and Aircraft Measurements for Satellites field campaign, a joint effort by CERES, MISR, MODIS-Atmospheres, and the NASA/GEWEX Global Aerosol Climatology Project (GACP) to validate satellite retrievals of atmospheric radiation and aerosol properties. CLAMS was conducted over a three week period in July 2001 in the vicinity of the Chesapeake Lighthouse, a stable sea platform located 20 km east of Virginia Beach, VA. from which NASA and NOAA make continuous longterm measurements of spectral and broadband radiation, meteorology and sea state. Five aircraft participated in the experiment including the NASA ER-2, the University of Washington Convair 580, the NASA Langley OV-10, Scaled Composites Inc. Proteus and a research Cessna 210. A complete description of the aircraft and surface instrumentation will be presented with an overview of the mission, the coordination with satellites and the atmospheric conditions that were encountered. Some preliminary results from the lighthouse and from the Langley OV-10 will be presented.