The origin, evolution and legacy of SEASAT

On the morning of June 26, 1978 a satellite was launched into Earth orbit from Vandenburg Air Force Base near Lompoc, California. The satellite, "SEASAT" opened a new age of space remote sensing using active radar to image and probe planetary processes. SEASAT began as a rough theme to use an array of active and passive microwave technologies, largely untried in space, to remotely sense synoptic ocean properties. This challenging prospect was the dream of scientists, aligned as the NASA sanctioned SEASAT Users Working Group", that had worked for more than five years to develop the appropriate sensor technologies and experiments for SEASAT. This group had staunchly championed the program throughout the approval and development process. This paper describes the epic SEASAT mission from its origin as an idea in 1972 until it became a reality collecting global ocean data in 1978. The path of the program is traced step-by-step through: definition studies performed by NASA Centers and the Navy Applied Physics Laboratory; establishment of the NASA SEASAT program Office in 1974 to develop the plan to secure mission level status and funding; identity as an approved new program in 1975; the selection of an industry team to implement SEASAT under the guidance of the Jet propulsion Laboratory; international expansion of the program with scientific participation and mission contributions (data collection stations, tracking sites, experiments) from Canada, Europe and Australia; the successful launch of SEASAT in June 1978, initiating a host of scientific demonstration and validation experiments; and the unexpected demise of SEASAT after 110 days in space. The paper concludes with a view of SEASAT\´s heritage expressed in terms of the derivative missions that have followed.