Captured on August 21, this image from NISAR’s L-band radar shows Maine’s Mount Desert Island. Green indicates forest, while magenta represents hard or regular surfaces, such as bare ground and buildings. The magenta area on the island’s northeast end is the town of Bar Harbor. Photo: Special Arrangement

ISRO’s launch vehicle GSLV-F16 carrying the NISAR earth observation satellite lifts off from the launch pad at the Satish Dhawan Space Centre, in Sriharikota, Andhra Pradesh, on July 30, 2025.
| Photo Credit: PTI

New Delhi:

The US-India NASA-ISRO Synthetic Aperture Radar or NISAR mission will observe the Earth down to the centimetre, monitoring its land and ice surfaces, NASA’s Jet Propulsion Laboratory Scientist Paul Rosen said.

The agreement was inked on 2014 to track changes in wetlands to ice sheets to infrastructure damaged by natural disasters through the dual band radar satellite, which will launch from ISRO’s Satish Dhawan Space Centre in Sriharikota in March.

How NISAR Will Work

The drum-shaped radar antenna reflector, measuring about 39 feet (12 meters) across, is among NASA’s contributions to the joint mission. It has been specially designed to help focus the transmitted and received microwave signals to and from the surface of the Earth.

NISAR will feature an L-band system with a 10-inch (25-centimeter) wavelength and an S-band system with a 4-inch (10-centimeter) wavelength. Microwaves can reflect or penetrate an object depending on their wavelength. Shorter wavelengths are more sensitive to smaller objects such as leaves and rough surfaces, whereas longer wavelengths are more reactive with larger structures like boulders and tree trunks.

This will enable NISAR to scan roughly all of the Earth’s land and ice surfaces twice every 12 days to collect scientific data.

A NASA-ISRO Collaboraton

Space Applications Centre Ahmedabad, ISRO’s lead center for payload development, is providing the mission’s S-band SAR instrument and is responsible for its calibration, data processing, and development of science algorithms to address the scientific goals of the mission. U R Rao Satellite Centre in Bengaluru, which leads the ISRO components of the mission, is providing the spacecraft bus. The launch vehicle is from ISRO’s Vikram Sarabhai Space Centre, launch services are through ISRO’s Satish Dhawan Space Centre, and satellite mission operations are by ISRO Telemetry Tracking and Command Network. National Remote Sensing Centre in Hyderabad is primarily responsible for S-band data reception, operational products generation, and dissemination.

NASA is providing the mission’s L-band Synthetic Aperture Radar (SAR), radar reflector antenna, the deployable boom, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem.

What Will Be The Outcome?

Key observations from NISAR will help researchers worldwide get unprecedented insights into the changes in the Earth’s surface, including the ice sheets, sea ice and glaciers. It will also monitor changes in the forest and wetland ecosystems, besides tracking the movement and deformation of the crust like landslides, earthquakes as well as volcanic activities.

“With NISAR, we’ll measure that change roughly every week, with each pixel capturing an area about half the size of a tennis court. Taking imagery of nearly all Earth’s land and ice surfaces this frequently and at such a small scale – down to the centimeter – will help us put the pieces together into one coherent picture to create a story about the planet as a living system,” Mr Rosen said.

The coverage from NISAR will help shape disaster response, producing data to assist in mitigating and assessing damage, with observations before and after catastrophic events available in short time frames.

How Will The Data Be Made Accessible?

Mr Rosen said that NASA decided the data would be processed and stored in the cloud, where it’ll be free to access.

ISRO chief S. Somnath on April 21 said that the Aditya L1 solar mission of the premier space research agency is continuously sending data about the Sun.
| Photo Credit: ANI

ISRO chief S. Somnath on April 21 said that the Aditya L1 solar mission of the premier space research agency is continuously sending data about the Sun.

Mr. Somnath, who was speaking to reporters here after being conferred a special award by jewellery major P.C. Chandra Group, said several instruments of the spacecraft are working continuously to feed data on many aspects.

“We are looking into the sun in a continuous manner – UV magnetic charges observation, corona graph observation, X-ray observation and other things,” he said.

India’s first solar mission craft, Aditya-L1 spacecraft was launched on September 2, 2023.

“As we are keeping this satellite for five years, the observation will be analysed as a long-term measure. It is not like your instant news that something has been reported about the sun today, something else will happen tomorrow, things will happen every day,” he explained.

All observations will happen now but the results will be known later, he said.

“Eclipse happens as the sun is blocked by the moon. It is not like that anything happens within the sun during an eclipse. But obviously, our mission is also collecting data about the sun before, during and after an eclipse, Mr. Somnath said, while answering a question on whether the mission will throw light on the solar eclipse.

Speaking about collaborations with other space agencies, he said ISRO is building a joint satellite NISAR (NASA-ISRO Synthetic Aperture Radar).

Representational image of a launch from Satish Dhawan Space Centre, in Sriharikota
| Photo Credit: PTI

A mission to study the Sun, and launching a climate observation satellite, a test vehicle as part of Gaganyaan human space flight programme and an Indo-US synthetic aperture radar — ISRO has a packed schedule following the highly anticipated landing of Chandrayaan-3 Lander.

In addition, XPoSat (X-ray Polarimeter Satellite), the country’s first dedicated polarimetry mission to study various dynamics of bright astronomical X-ray sources in extreme conditions, is also ready for launch, an ISRO official said on Tuesday.

Aditya-L1, the first space-based Indian observatory to study the Sun, is getting ready for the launch, most likely in September first week.

According to ISRO Chairman, Somanath S, the space agency has also lined up the launch of a climate observation satellite INSAT-3DS.

The launch of a test vehicle mission, for the validation of the crew escape system for Gaganyaan, the country’s maiden human space flight mission, is also expected soon.

NISAR

“(Then) we have to launch NISAR, the India-U.S. built Synthetic Aperture Radar,” Mr. Somanath said in his independence day address at ISRO headquarters here on August 15. “So, our hands are full.”

“We are going to build a large number of satellites for our security purpose as well in the coming days,” Mr. Somanath had said.

According to ISRO officials, NASA-ISRO SAR (NISAR) is a Low Earth Orbit (LEO) observatory being jointly developed by U.S. space agency NASA and ISRO.

NISAR will map the entire globe in 12 days and provide spatially and temporally consistent data for understanding changes in Earth’s ecosystems, ice mass, vegetation biomass, sea level rise, ground water and natural hazards including earthquakes, tsunamis, volcanoes and landslides, they said.

“It carries L and S dual band Synthetic Aperture Radar (SAR), which operates with Sweep SAR technique to achieve large swath with high resolution data. The SAR payloads mounted on Integrated Radar Instrument Structure (IRIS) and the spacecraft bus are together called an observatory”, an ISRO official noted.

Unmanned missions ahead of Gaganyaan

Before undertaking the Gaganyaan human space (manned) flight mission, ISRO has planned two unmanned missions.

“We are getting ready for the (first of the two) unmanned crew module mission by the beginning of next year”, an ISRO official said.

The objective of the Gaganyaan mission is to demonstrate the capability of conducting human space flight mission to LEO on-board Indian Launch vehicle. The Orbital module consists of a Crew module and a Service module.

Crew module, which is a pressurised module, acts as living quarters for the crew. The orbital module will be positioned in approximately 400 km circular orbit around earth for one to 3 days and the crew module will return at the designated location at sea.