NASA's NISAR Project Manager Phil Barela (with hands raised) speaks with Indian Space Research Organisation Chairman S. Somanath about the NASA-ISRO Synthetic Aperture Radar (NISAR) science instrument payload in a clean room at NASA's Jet Propulsion Laboratory in Southern California on Feb. 3, 2023. Somanath was among a group of visitors to the facility that included officials from NASA, ISRO, and the Indian Embassy.

The NISAR mission – a joint effort between NASA and ISRO – will measure changes to Earth's land ice surfaces down to fractions of an inch. Data collected by this satellite will help researchers monitor a wide range of changes critical to life on Earth in unprecedented detail. This includes spotting warning signs of imminent volcanic eruptions, helping to monitor groundwater supplies, tracking the melt rate of ice sheets tied to sea level rise, and observing shifts in the distribution of vegetation around the world. The data will inform humanity's responses to urgent challenges posed by natural disasters and climate change, and help communities prepare for and manage hazards.

There are two instruments on the satellite that will send and receive radar signals to and from Earth's surface to make the mission's measurements. An L-band synthetic aperture radar (SAR), which uses a signal wavelength of around 9 inches (24 centimeters), and an S-band SAR with a signal wavelength of nearly 5 inches (12 centimeters). Both will bounce their microwave signal off of the planet's surface and record how long it takes the signal to make one roundtrip, as well as the strength of that return signal. This enables the researchers to calculate the distance from the spacecraft to Earth's surface and thereby determine how the land or ice is changing. An antenna reflector nearly 40 feet (12 meters) in diameter, supported by a deployable boom, will focus the microwave signals sent and received by the SARs.

JPL, which is managed for NASA by Caltech in Pasadena, leads the U.S. component of NISAR and is providing the mission's L-band SAR instrument. 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.