The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite has opened public access to data from both its radar instruments as of 20 July, offering researchers an unprecedented view of Earth's surface — including a striking Antarctic landscape that resembles a hummingbird in flight. The milestone comes just days before the first anniversary of NISAR's launch from Satish Dhawan Space Centre in India on 30 July 2025.

The Antarctic Image That Caught Scientists' Attention

NASA released an early radar image on Tuesday showing Nunatak Zaterjavshijsja, a mountaintop in East Antarctica, rising through ice that flows northeast toward the ocean. The fractured glacier forms an outline that scientists and engineers say resembles a hummingbird. Deep crevasses appear as sharp green lines in the radar image, while smoother ice surfaces register as magenta.

'First, it's a beautiful image, with rich details of features that provide insights to how the glacier is moving. Then, because radar can often see through snow and deep into the ice, NISAR can observe fundamentally different properties of Antarctic ice than can be seen in optical imagery,' said Seongsu Jeong, signal analysis engineer at NASA's Jet Propulsion Laboratory in Southern California, who produced the image. 'With NISAR we're seeing what's hidden beneath the surface.'

The image was generated from L-band measurements collected in August 2025 during systems testing. Its colours reflect how polarised microwave signals interacted with the ice — horizontally polarised returns from smoother surfaces appear magenta, vertically polarised returns from crevasse walls or refracted signals appear green, and white areas indicate a strong blend of both scattering types.

What the Data Covers and How It Is Released

ISRO's Space Applications Centre in Ahmedabad has begun releasing S-band data through the Bhoonidhi portal. On the US side, calibrated L-band products collected since 17 June are now being released continuously. Earlier releases had included sample products in January and thousands of pre-calibrated products in February.

The mission generates dozens of terabytes of science data each day and scans from near the South Pole to 77.5 degrees north, above the Arctic Circle. Its 12-metre drum-shaped reflector is the largest radar antenna reflector NASA has ever sent into space.

Why NISAR Matters for Earth Science

Synthetic aperture radar can collect observations through cloud cover and in complete darkness — capabilities that conventional optical instruments lack. This makes NISAR especially valuable for detecting gradual surface movement and rapid changes triggered by earthquakes, landslides, floods, and other natural events. Since launch, mission teams have calibrated instruments, refined processing algorithms, and monitored nearly all land and ice-covered surfaces twice every 12 days.

The satellite's data can help researchers track the movement of land and ice, monitor forests and wetlands, and support hazard response. Notably, this is the first satellite mission jointly developed by NASA and ISRO, building on years of US-India civil space cooperation that includes NASA instruments flown aboard India's Chandrayaan-1 lunar mission.

What Comes Next

Teams in both the United States and India will continue releasing processed files from the L-band and S-band radars. With public data access now fully open and the first operational year nearing its close, the scientific community is expected to begin publishing findings from NISAR's observations in the months ahead — potentially reshaping understanding of ice dynamics, land subsidence, and ecosystem change at a global scale.