Free and open: NISAR data now accessible worldwide
The NASA-ISRO Synthetic Aperture Radar satellite, known as NISAR, reached a milestone on July 20, 2026, when processed data from its two onboard radar instruments became publicly available. Both NASA and ISRO are releasing data files on a rolling basis, giving researchers, institutions, and independent users access to observations collected by the satellite's L-band and S-band radar systems.
This dual-frequency configuration sets NISAR apart from most Earth observation platforms currently in orbit. The L-band radar, provided by NASA, penetrates dense vegetation canopies and ice sheets to measure subsurface and structural changes. The S-band radar, developed by ISRO, delivers complementary detail on surface features. Together, the two instruments can track glacier movement, ground deformation, agricultural conditions, and natural hazard zones across the globe, all from a single satellite.
A rocky peak, a fractured flow, and an unexpected silhouette
One of the first images released under the open-data initiative captures Nunatak Zaterjavshijsja, a bare rock summit protruding through the East Antarctic Ice Sheet. The term nunatak — borrowed from Greenlandic — describes any mountain peak or ridge that rises above an otherwise continuous ice surface without being buried by it.
In this part of Antarctica, the surrounding ice sheet moves steadily toward the northeast, eventually draining into the Southern Ocean. The nunatak acts as a rigid obstacle in the middle of that flow, forcing the ice to split and fracture as it moves around the rocky obstruction. When rendered from NISAR's L-band radar data, the resulting network of crevasses and flow lines forms a shape that closely resembles a hummingbird in flight — a detail that quickly caught the attention of the teams processing the imagery.
The visual effect is striking, but the scientific content underneath it is equally significant. The fracture patterns visible in the image carry direct information about ice stress, flow velocity gradients, and the mechanical behavior of the ice sheet — all critical inputs for climate models tracking polar ice loss.
A long-term monitoring tool built on international cooperation
NISAR is designed to revisit nearly the entire land surface of Earth approximately every twelve days. That cadence, combined with the sensitivity of its two radar bands, positions the satellite as a long-duration monitoring platform capable of detecting even subtle changes in terrain over time. The ongoing data releases from both NASA and ISRO will allow the scientific community to build continuous records stretching across years.
The mission also stands as a template for large-scale bilateral space cooperation. NASA contributed the L-band radar, communication systems, and part of the data processing infrastructure. ISRO designed and built the spacecraft, developed the S-band radar, and managed the launch. The division of responsibilities between the two agencies reflects a model that other international partners may look to when structuring future Earth observation collaborations.
Opening the archive to the public transforms NISAR from an operational satellite into a shared scientific resource — one whose full potential is only beginning to be explored.
