The NASA-ISRO SAR Mission: A summary

The National Aeronautics and Space Administration (NASA) in the United States and the Indian Space Research Organisation (ISRO) have developed the NASA-ISRO Synthetic Aperture Radar (NISAR) mission, planned for launch in 2025. The mission will use SAR to map Earth’s solid surfaces every 12 days, persistently on ascending and descending portions of the orbit, over all land and ice. The mission’s primary objectives will be to study Earth’s land and ice deformation and ecosystems in areas of common interest to the U.S. and Indian science communities. This single observatory solution with L-band (24-cm wavelength) and S-band (9.4-cm wavelength) imaging radars has a swath of more than 240 km at 5–10-m resolution, using full polarimetry where needed. The data will be processed into a suite of products in radar-specific and geographic coordinates tailored to the needs of each science discipline. The product suite is designed to be analysis ready and will be freely and openly available. To achieve these unprecedented capabilities, both radars use a reflector-feed system whereby the feed aperture elements are individually sampled to allow a scan-on-receive capability at both the L band and S band. The project is preparing for launch at the integration and test facilities in India. The launch will take place at the Satish Dhawan Space Center in India on ISRO’s Geosynchronous Launch Vehicle (GSLV) Mark II. NISAR will be launched into a sun-synchronous polar orbit at a 748-km altitude with an exact 12-day repeat cycle. This article summarizes the mission, the science, the measurements, and plans for commissioning and early operations.