Ocean Surface Wind Vector Measurements from Space
The SED is working in conjunction with NRL's Remote Sensing Division to develop WindSat. The WindSat program is sponsored by Operational Navy (OPNAV) through the Office of Naval Research (ONR), and the National Polar-orbiting Operational Environmental Satellite System (NPOESS).
The SED is designing, building, and testing the spacecraft, integrating it with the commercial satellite bus provided by the Air Force Space and Missile Command Space Test Program (STP), and conducting combined systems testing.
WindSat is a demonstration program to evaluate the capability to exploit passive microwave polarimetry to measure the full ocean surface wind field (wind speed and wind direction) from space.
The sensor in the NRL's WindSat payload is a multi-frequency polarimetric microwave radiometer that passively measures microwave radiation emitted naturally from the ocean's surface and quantifies these measurements in terms of the brightness temperature. In microwave measurement systems, the amount of radiation detected depends on the properties of the scene and the observation frequency.
Wind roughening the surface of the ocean causes an increase in the brightness temperature of the microwave radiation emitted from the water's surface. Recent airborne experiments conducted jointly by NRL and the Jet Propulsion Laboratory indicate that by understanding the relationship between wind speed and surface roughness, an observer can determine not only the speed of winds at the ocean's surface but also their direction.
Integration and test will take place at NRL's Payload Processing Facility in Washington, DC WindSat will launch on a medium class expendable launch vehicle into a sun-synchronous orbit in December 2001.