The NISAR Antarctica hummingbird image, a false-colour synthetic aperture radar map of a mountaintop in East Antarctica’s Prince Charles Mountains, has given glaciologists their clearest view yet of ice-flow dynamics beneath one of the most inaccessible terrains on Earth. Released by NASA on 21 July, the image was captured by NISAR’s L-band Synthetic Aperture Radar in August 2025 and depicts the Nunatak Zaterjavshijsja, a subglacial peak that disrupts the flow of an ice stream moving northeast towards the ocean.
What the NISAR Antarctica Hummingbird Image Actually Shows
The striking combination of magenta, green, and white in the image is artificial: it is not a photograph but a radar map constructed from polarised microwave signals. NASA explained in its press release that NISAR transmits radar waves with a horizontal polarisation and that the orientation of the returning signals (horizontal, vertical, or both) provides information about the surface that reflected them. Magenta areas indicate smooth ground; green indicates rough, cracked terrain.
As the moving glacier pushes against the Nunatak Zaterjavshijsja, the pressure fractures ice into deep crevasses, rendered as vibrant green lines across the map. These cracks are not new damage, and the obstruction itself is not a cause for alarm. What is new is the precision with which NISAR can chart them. Seongsu Jeong, the signal analysis engineer who produced the image at NASA’s Jet Propulsion Laboratory in Southern California, said: ‘First, it’s a beautiful image, with rich details of features that provide insights into 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. With NISAR we’re seeing what’s hidden beneath the surface.’
That capability matters for sea-level projections. NISAR’s ability to map glacier movement at this resolution allows glaciologists to track how fast Antarctic glaciers are advancing and to model how they could affect future global sea-level rise.
A Joint Mission Built on Shared Hardware and Open Data
NISAR is a collaboration between NASA and ISRO, the Indian Space Research Organisation. According to Eos, each agency provided one of the radar systems, as well as other components of the satellite, the launch system, and the data management infrastructure. NASA contributed the L-band radar; ISRO contributed the S-band radar, and the Indian side has already begun releasing S-band data. The US team’s L-band data from earlier operations is expected to be fully released by the end of the year, with files available for download at the Alaska Satellite Facility Distributed Active Archive Center in Fairbanks.
According to eoPortal, the satellite launched on 30 July 2025 at 12:10 UTC from India’s Satish Dhawan Space Centre aboard ISRO’s GSLV-F16 rocket. The 21 July image release came as the mission approached that first operational anniversary. eoPortal also confirms that all NISAR science data, covering both L- and S-band, will be freely and openly available to the public, consistent with NASA’s long-standing Earth Science open data policy.
Overcoming the Imaging Challenges of Polar Terrain
Antarctica has historically been one of the hardest places on Earth to image from space. Severe lighting constraints, extreme environmental conditions, and orbital limitations have all hampered traditional optical satellites, which require sunlight to operate. NISAR sidesteps those constraints through several design choices.
The spacecraft carries a 12-metre drum-shaped deployable wire-mesh radar antenna reflector, the largest NASA has ever launched. Rather than waiting for sunlight, NISAR actively transmits its own L-band and S-band microwave radar signals, allowing it to image through winter darkness and thick cloud cover alike. A 12-day repeat-pass interferometric orbit means that even East Antarctica (described in the report as the most remote and isolated region on Earth) receives a fresh, detailed map every 12 days, year-round.
That cadence is central to the mission’s broader objectives: tracking natural disasters, monitoring ecosystems and crops, and analysing the movement of melting glaciers and ice sheets to understand changes in the Earth’s surface. The hummingbird-shaped NISAR map is an early demonstration of what that 12-day rhythm can produce in one of the world’s least-understood environments.
With the full L-band archive set for public release before the end of the year, researchers and agencies worldwide will gain unrestricted access to the kind of sub-surface polar data that was simply unavailable before NISAR became operational.
