The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) will be the first ocean color satellite since the Nimbus-7 Coastal Zone Color Scanner (CZCS), which ceased operation in 1986. Unlike the CZCS, which was designed as a proof-of-concept experiment, SeaWiFS will provide routine global coverage every two days and is designed to provide estimates of photosynthetic pigment concentrations of sufficient accuracy for use in quantitative studies of the ocean's primary productivity and biogeochemistry. A review of the CZCS mission is included that describes the limitations of that data set and provides justification for a comprehensive SeaWiFS calibration and validation program. To accomplish the scientific objectives of the mission, the sensor's calibration must be constantly monitored, and robust atmospheric correction and bio-optical algorithms must be developed. The plan incorporates a multi-faceted approach to sensor calibration using a combination of vicarious (based on {\it in situ} observations) and onboard calibration techniques. Because of budget constraints and the limited availability of ship resources, the development of the operational algorithms (atmospheric and bio-optical) will rely heavily on collaborations with the Earth Observing Satellite (EOS), the Moderate Resolution Imaging Spectrometer (MODIS) oceans team, and projects sponsored by other agencies, e.g., the United States Navy and the National Science Foundation (NSF). Other elements of the plan include the routine quality control of input ancillary data (e.g., surface wind, surface pressure, ozone concentration, etc., used in the processing and the verification of the level-0 (raw) data to level-1 (calibrated radiances), level-2 (derived products) and level-3 (gridded and averaged derived data) products.
