The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite, described as the most advanced Earth-imaging spacecraft sent to space, completes one year of operational service this month.
NISAR, a joint project of the Indian Space Research Organisation (ISRO) and the US National Aeronautics and Space Administration (NASA), was launched from ISRO’s Satish Dhawan Space Centre on the southeastern coast on July 30, 2025. Following the deployment of its systems, calibrations and checks, it was declared mission-ready in August.
“NASA-ISRO Mission Aces Checkouts, on Track to Start Delivering Science,” NASA posted on its website on August 28, 2025. The spacecraft had deployed its giant 39-foot-diameter radar antenna reflector on August 15, following which engineers powered on and checked its L-band and S-band synthetic aperture radar (SAR) systems, designed to track movement of Earth’s ice and land surfaces in unprecedented detail.
Launched aboard ISRO’s GSLV F16 rocket, NISAR was raised to its final operational orbit at a mean altitude of 747 km above Earth on August 26. It is the first space mission to carry two SAR systems.
The L-band radar transmits and receives signals at a 10-inch wavelength, enabling it to penetrate forest canopies and measure soil moisture, forest biomass and the movement of land and ice surfaces.
The S-band radar, which uses a 4-inch wavelength, is more sensitive to smaller vegetation and is suited to observing certain types of agriculture, grassland ecosystems and moisture in snow. Both systems can collect data through clouds and precipitation, day and night.
The satellite will monitor most of Earth’s land and ice surfaces twice every 12 days, tracking changes in forests, frozen surfaces, major infrastructure and the planet’s crust with sub-inch precision. The latter is crucial for understanding how land surfaces move before, during and after earthquakes, volcanic eruptions and landslides, NASA said.
ISRO’s Space Applications Centre provided the mission’s S-band SAR, while the UR Rao Satellite Centre provided the spacecraft bus — the satellite platform on which the sensors are mounted. After launch, key operations, including the deployment of the boom and radar antenna reflector, have been executed and monitored by ISRO’s Telemetry, Tracking and Command Network through a global network of ground stations.
NASA’s Jet Propulsion Laboratory (JPL) in Southern California was responsible for the L-band SAR, reflector, boom, high-rate communication subsystem for science data, solid-state data recorder and payload data subsystem. NISAR’s L-band data is received by NASA’s Near Space Network at the Goddard Space Flight Center in Maryland.
“NISAR continues to systematically collect precious data to understand the Earth’s dynamics to drive advancements across multiple scientific disciplines, including ecosystem, solid earth, cryosphere, hydrology, oceanography, coastal-processes, geoscience and disaster response,” ISRO said in a statement marking one year of operations.
NISAR is the first mission to systematically and globally study the solid Earth, ice masses and ecosystems, areas that are currently sparsely sampled. According to the National Remote Sensing Centre, which processes NISAR products, the addition of the S-band considerably extends measurement sensitivity alongside the L-band while reducing sensitivity to ionospheric and soil-moisture effects.
