The S-band SAR arrived at JPL on March 19. The next day, technicians and engineers moved the S-SAR into the airlock to the Spacecraft Assembly Facility's High Bay 1 clean room, to be unpacked over several days in the clean room.

The NISAR mission is a collaboration between NASA and the Indian Space Research Organization (ISRO) that will use two kinds of synthetic aperture radar (SAR) to track subtle changes in Earth's surface: S-band SAR and L-band SAR. (The "S" and "L" denote the wavelength of their signal.) On March 19, 2021, the assembly, test, and launch team at NASA's Jet Propulsion Laboratory in Southern California received the S-band SAR from its partner in India.

NISAR, short for NASA-ISRO SAR, will spot warning signs of imminent volcanic eruptions, help to monitor groundwater supplies, track the melt rate of ice sheets tied to sea level rise, and observe shifts in the distribution of vegetation around the world.

JPL, which is managed for NASA by Caltech in Pasadena, California, leads the U.S. component of the NISAR mission in addition to providing the project's L-band SAR. NASA is also providing the radar reflector antenna, the deployable boom, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder, and payload data subsystem. ISRO is providing the spacecraft bus, the S-band SAR, the launch vehicle, and associated launch services and satellite mission operations.