THE NASA-ISRO SAR Mission

The National Aeronautics and Space Administration(NASA) in the United States and the Indian Space ResearchOrganisation (ISRO) have developed the NASA-ISRO SyntheticAperture Radar (NISAR) mission, planned for launch in 2025.The mission will use synthetic aperture radar to map Earth solidsurfaces every 12 days, persistently on ascending and descendingportions of the orbit, over all land and ice. The mission’s primaryobjectives will be to study Earth land and ice deformation,and ecosystems, in areas of common interest to the US andIndian science communities. This single observatory solution withL-band (24 cm wavelength) and S-band (9.4 cm wavelength)imaging radars has a swath of over 240 km at 5-10 m resolution,using full polarimetry where needed. The data will be processedto a suite of products in radar-specific and geographic coordinatestailored to the needs of each science discipline. The productsuite is designed to be analysis-ready and will be freely andopenly available. To achieve these unprecedented capabilities,both radars use a reflector-feed system, whereby the feed apertureelements are individually sampled to allow a scan-on-receivecapability at both L-band and S-band. The project is preparingfor launch at integration and test facilities in India. The launchwill take place at the Satish Dhawan Space Centre in Indiaon ISRO’s Geosynchronous Launch Vehicle (GSLV) Mark II.NISAR will be launched into a sun-synchronous polar orbit at748 km altitude with an exact twelve-day repeat cycle. This articlesummarizes the mission, the science, the measurements, and plansfor commissioning and early operations.