Surface Water and Ocean Topography (SWOT)

The Surface Water and Ocean Topography (SWOT) satellite is a joint mission of NASA, CNES, the Canadian Space Agency, and the UK Space Agency, launched on 16 December 2022 on a SpaceX Falcon 9 from Vandenberg Space Force Base.^[1] SWOT operates in a 891 km non-sun-synchronous orbit at 78-degree inclination with a 21-day exact-repeat cycle, achieving global coverage of water bodies and oceans between high-latitude limits with approximately 11-day mid-latitude revisits.^[2] The primary instrument, KaRIn (Ka-band Radar Interferometer), illuminates a 120 km dual-swath footprint and derives water surface elevation and extent at sub-kilometre resolution - the first spaceborne wide-swath radar interferometer in orbit.^[3] A nadir Poseidon-3C altimeter provides conventional along-track sea surface height continuity, and an Advanced Microwave Radiometer corrects for tropospheric path delay.^[3] SWOT addresses inland hydrology (lake and river water levels, floodplain inundation) and ocean mesoscale and sub-mesoscale circulation at resolutions previously unresolvable from space.^[4]