NISAR, the NASA-ISRO Radar Satellite Launched on 30 July 2025, Has Now Mapped a Sinking Mexico City, the Ground Shift After a Venezuelan Earthquake and an Erupting Kamchatka Volcano

On 30 July 2025, an Indian GSLV Mk II rocket lifted a 12-metre radar dish folded inside a satellite off the pad at Sriharikota. The satellite is NISAR, short for NASA-ISRO Synthetic Aperture Radar, and it is the first free-flying mission to carry two radars of different wavelengths. Since 20 July 2026 the public can download data from both.

NASA’s mission page gives its goal as measuring “changes in Earth’s land, ice, water, and vegetation.” Synthetic aperture radar (SAR) is the method: the satellite sends microwave pulses down, records the echoes as it moves, and combines them into an image. Radar supplies its own signal, so it works at night and through cloud, including the cloud of the monsoon.

Who built what

The split is written out on ISRO’s mission page. NASA supplied the L-band radar, the 12-metre reflector, the 9-metre boom that holds it away from the spacecraft, a solid-state data recorder, a GPS receiver and a high-speed downlink. ISRO supplied the spacecraft bus (the main body that carries power, computers and thrusters), the S-band radar, data handling, the downlink and the launch system.

JPL’s launch-era release adds the credits by centre: ISRO’s U R Rao Satellite Centre built the bus, its Space Applications Centre in Ahmedabad built the S-band radar, and its Vikram Sarabhai Space Centre provided the launch vehicle. ISRO handles commanding and operations. NASA provides the orbit-manoeuvre plan and the radar operations plan.

ISRO says the payloads and mainframe took 8 to 10 years to develop. The radar structure was assembled and tested at JPL, then shipped to ISRO. For the agency’s wider record on a small budget, see ISRO the frugal space power; its other orbital milestone of 2025 was SpaDeX docking.

A 12-metre mesh dish and a 242 km swath

Astro Aerospace, a Northrop Grumman company, built the reflector from gold-plated wire mesh, according to NASA. At 12 metres it is the largest radar antenna reflector the agency has sent into space, and it launched folded.

Per ISRO’s statement, as reported by the Press Trust of India on 28 November 2025, the boom joints began unfolding on 9 August 2025 and took five days. The reflector opened on 15 August, and ISRO called the antenna performance satisfactory.

The dish is there to widen the picture, since a radar normally trades coverage for detail. A technique called SweepSAR, developed by JPL with the German space agency DLR, gets around that. In it the feed transmits a narrow strip of energy at the reflector, which spreads it across the ground. On the return, the feed sweeps its beam across the reflector and picks up echoes from the whole strip at once. The swath on the ground is 242 km, NASA’s SweepSAR page says.

L-band resolution is 7 metres along the track and 2 to 8 metres across it, depending on mode, per NASA. Overall, the mission overview gives 3 to 10 metres. Width has a price: the radar cannot listen while it transmits, which leaves gaps. Varying the pulse rate moves the gaps around, and the data are filled in afterwards.

Two wavelengths, one field

On NASA’s satellite page the L-band wavelength is 24 cm and the S-band is 9.4 cm. Longer waves go deeper. L-band can, NASA says, pass through tree canopies and measure soil moisture and ground motion down to fractions of an inch. The shorter S-band, JPL says, is more sensitive to small vegetation, which suits some crops and grassland.

Together, the two bands see different layers of the same scene. Under some conditions L-band also penetrates snow and ice, the Earthdata release adds.

Orbit height is about 747 km, in a Sun-synchronous orbit (one that crosses each latitude at the same local time) inclined 98.4 degrees. The exact ground track repeats every 12 days. Coverage runs from a few degrees off the South Pole to 77.5 degrees north, and nearly all land and ice is imaged twice in each 12-day cycle, on north-bound and south-bound passes, JPL says. The mission produces dozens of terabytes of data a day.

What it is meant to measure

The objectives on ISRO’s mission page are specific. They name woody biomass and its change, crop extent, wetland extent, the Greenland and Antarctic ice sheets, sea ice and mountain glaciers. They also name ground deformation from earthquakes, volcanoes and landslides, and sinking or rising land over aquifers and oil and gas reservoirs.

The deformation work uses interferometry (InSAR), which compares two radar passes over the same place. A change in the distance between satellite and ground shows up as a shift in the radar phase, which is how NASA describes the Venezuela map below.

From launch to the first pictures

Liftoff was scheduled for 17:40 IST on 30 July 2025. By mid-September 2025 the satellite had reached its operational orbit, JPL says.

The first images came within weeks of launch. ISRO’s first S-band image, taken on 19 August 2025, covers the Godavari delta in Andhra Pradesh. On 25 September 2025, JPL released two L-band images: Maine’s Mount Desert Island on 21 August and farmland and wetlands near North Dakota’s Forest River on 23 August.

On 28 November 2025 ISRO announced that the mission had entered its science phase and released a set of S-band first-look images, among them the Chilika lagoon, the Vembanad wetland, the Koshi barrage and Rennick Glacier in Antarctica. On 29 January 2026, JPL published an L-band image of the Mississippi River Delta from 29 November 2025, a day on which cloud blocked optical satellites over the region.

What it has found so far

In Antarctica, Seongsu Jeong, a JPL signal analysis engineer, produced an L-band image, from August 2025 test data, of Nunatak Zaterjavshijsja, a mountaintop in East Antarctica, where crevasses show as sharp green lines in the flowing ice. “With NISAR we’re seeing what’s hidden beneath the surface,” he said. A Landsat 9 optical image of the same site, taken on 2 November 2025, looks nearly all white.

JPL’s Mexico City map covers 25 October 2025 to 17 January 2026 and shows parts of the city sinking by up to a few centimetres a month. Those measurements are preliminary. Parts of the metro area sank about 35 cm a year in the 1990s and 2000s, NASA notes.

In Venezuela, a magnitude 7.2 earthquake struck the north on 24 June 2026, followed less than a minute later by a magnitude 7.5 mainshock, NASA Earth Observatory says. NISAR images from 25 and 30 June, compared with passes on 13 and 18 June, showed ground just south of one fault section moved west by as much as 60 cm. NASA says USGS used the data to refine its model of how the fault slipped, and that this was the first use of NISAR’s Urgent Response system, which can deliver data within 12 to 24 hours, on a large earthquake.

On Kamchatka, a magnitude 8.8 earthquake struck offshore on 30 July 2025, the day NISAR launched. A few days later the Krasheninnikov volcano began erupting for the first time in nearly five centuries, per NASA. The satellite’s first image of it came on 25 December 2025, and a 17-frame time-lapse released on 24 September 2026 runs to mid-August 2026, showing lava filling the inner caldera and spreading in a fan. Matthew Pritchard, a Cornell geophysicist on the science team, said the team is seeing volcanoes “that we’ve never really had eyes on like this before.”

How to get the data

The policy is free and open. L-band products sit in the Alaska Satellite Facility Distributed Active Archive Center in Fairbanks and reach users through NASA Earthdata. About 25 sample products came out in January 2026 and thousands of pre-calibrated L-band products in February, JPL says. Calibrated data followed on 20 July 2026, covering observations from 17 June 2026 on. Earlier science data are being added, with the full record expected by the end of 2026, and the Earthdata page labels all of it provisional.

S-band data go through ISRO’s Bhoonidhi portal, where registered users can search and download. A release page dated 24 July 2026 says products from cycle 25, which began on 8 July 2026, come from the operational production system, and that earlier data will be reprocessed in phases. The page lists known limits: residual banding in low-signal areas such as oceans and deserts, and possible leftover radio interference. Sample images include the Brahmaputra in Assam, Nagapattinam in Tamil Nadu and Mount Rinjani in Indonesia, all from July 2026.

Where the published figures differ

The two agencies do not give identical numbers. A pre-launch notice from ISRO targeted a 743 km orbit, while its mission page and NASA both give 747 km for the operating orbit. Swath is 242 km on NASA’s SweepSAR page and in ISRO’s launch notice, and “about 240 km” elsewhere on ISRO’s pages.

Mission life differs more. NASA’s overview lists a baseline of 3 years, ISRO’s mission page says 5 years, and NASA adds that extended operations may be led by ISRO. No cost figure appears on any NASA or ISRO page we opened.