The NISAR satellite, a joint U.S.-India mission that launched in July 2025, has begun releasing calibrated data from its L-band and S-band radar instruments as of July 20. Teams from NASA and ISRO will continue releasing processed files on an ongoing basis to help researchers track land and ice movement, monitor ecosystem changes, and respond to natural hazards. The mission marks the first anniversary of NISAR's launch and represents the first free-flying space mission to carry two radar instruments at different wavelengths.
Since launch, NISAR has monitored nearly all the planet's land and ice surfaces twice every 12 days, capturing detailed imagery of urban areas, agricultural fields, landslides, earthquakes, and subsiding ground in Mexico City. The satellite's L-band radar can penetrate snow and ice to reveal subsurface structure, while its S-band system observes different properties depending on wavelength. An early Antarctic image shows Nunatak Zaterjavshijsja, a mountaintop in East Antarctica surrounded by fractured ice, which resembles a hummingbird in shape -- a feature that becomes visible only through radar's ability to see through snow.
The Antarctic image demonstrates the complementary strengths of NISAR's dual radar systems. The L-band radar transmits horizontally polarized waves, with returning signals indicating surface properties: horizontal polarization (shown in magenta) suggests smooth ice, while vertical polarization (green) indicates crevasses and irregular surfaces where signals scatter or refract through the ice. The same scene viewed through optical satellite imagery appears nearly featureless white, highlighting radar's advantage for ice studies.
The U.S. mission team began continuous L-band data release on July 20 for all measurements collected since June 17, with plans to release all earlier science data by year's end. India's science team has started releasing S-band data via the Bhoonidhi portal. NISAR generates dozens of terabytes of data daily and covers nearly all land and ice surfaces from the South Pole to 77.5 degrees north latitude. Users can access L-band files through the Alaska Satellite Facility Distributed Active Archive Center.