File:SWOT Satellite's Land 'First Light' (PIA25774).jpg

This visualization shows water features on New York's Long Island – shown as bright pink splotches nestled within the landscape. Purple, yellow, green, and dark blue shades represent different land elevations, while the surrounding ocean is a lighter blue. The data was collected on Jan. 21, 2023, by an instrument on the Surface Water and Ocean Topography (SWOT) satellite called the Ka-band Radar Interferometer (KaRIn).

KaRIn is the scientific heart of the SWOT mission. It's a radar instrument with one antenna at each end of a boom that’s 33 feet (10 meters) long. This enables KaRIn to look off to either side of a center line directly below the satellite as the instrument bounces microwave signals off of Earth's surface. The returning radar signals arrive at each antenna slightly out of step, or phase, from one another. When these signals are combined with other information about the antennas and the satellite's altitude, scientists will be able to map the height of water on Earth's surface with never-before-seen clarity.

This initial inland image is a tantalizing indication of how SWOT can measure details of smaller lakes, ponds, and rivers in ways that satellites could not before. Such data will be used to produce an extraordinary accounting of the freshwater on Earth's surface in ways useful to researchers, policymakers, and water resource managers.

Led by NASA and the French space agency Centre National d'Études Spatiales (CNES), SWOT will measure the height of water on over 90% of Earth's surface, providing a high-definition survey of our planet's water for the first time. The satellite's measurements of freshwater bodies and the ocean will provide insights into how the ocean influences climate change; how a warming world affects lakes, rivers, and reservoirs; and how communities can better prepare for floods and other disasters.

Launched on Dec. 16, 2022, from Vandenberg Space Force Base in central California, SWOT is now in a six-month period called commissioning, calibration and validation. This is when engineers on the mission check out the satellite's systems and science instruments to ensure data accuracy before the start of science operations in July.

SWOT was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA's Jet Propulsion Laboratory, which is managed for the agency by Caltech in Pasadena, California, leads the U.S. component of the project. For the flight system payload, NASA provided the Ka-band Radar Interferometer (KaRIn) instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. CNES provided the Doppler Orbitography and Radioposition Integrated by Satellite (DORIS) system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations. CSA provided the KaRIn high-power transmitter assembly. NASA provided the launch vehicle and the agency's Launch Services Program, based at Kennedy Space Center, managed the associated launch services.