By R Anil Kumar
- Weighing over 2.8 tons and costing $1.3 billion, NISAR is the most expensive Earth observation satellite ever built. Its mission: to track minute changes in Earth’s surface-down to fractions of an inch-caused by earthquakes, landslides, volcanic eruptions, glacier movements, and forest degradation. The data it collects will be vital for disaster preparedness, infrastructure monitoring, and climate resilience
Washington/ New Delhi, September 25, 2025. The NISAR (NASA-ISRO Synthetic Aperture Radar) Earth-observing radar satellite’s first images of our planet’s surface are in, and they offer a glimpse of things to come as the joint mission between NASA (National Aeronautics and Space Administration) and ISRO (Indian Space Research Organisation) approaches full science operations later this year.
“Launched under US President Donald Trump in conjunction with India’ s Prime Minister Narendra Modi, NISAR’s first images are a testament to what can be achieved when we unite around a shared vision of innovation and discovery,” said acting NASA Administrator Sean Duffy.
“This is only the beginning. NASA& ISRO will continue to build upon the incredible scientific advancements of the past and present as we pursue our goal to maintain our nation’s space dominance through Gold Standard Science.”
Images from the spacecraft, which was launched by ISRO on July 30, display the level of detail with which NISAR scans Earth to provide unique, actionable information to decision-makers in a diverse range of areas, including disaster response, infrastructure monitoring, and agricultural management.
“By understanding how our home planet works, we can produce models and analysis of how other planets in our solar system and beyond work as we prepare to send humanity on an epic journey back to the Moon and onward to Mars,” said NASA Associate Administrator Amit Kshatriya.
“The successful capture of these first images from NISAR is a remarkable example of how partnership and collaboration between two nations, on opposite sides of the world, can achieve great things together for the benefit of all.”
On Aug. 21, the satellite’s L-band synthetic aperture radar (SAR) system, which was provided by NASA’s Jet Propulsion Laboratory in Southern California, captured Mount Desert Island on the Maine coast. Dark areas represent water, while green areas are forest, and magenta areas are hard or regular surfaces, such as bare ground and buildings. The L-band radar system can resolve objects as small as 15 feet (5 meters), enabling the image to display narrow waterways cutting across the island, as well as the islets dotting the waters around it.
Then, on Aug. 23, the L-band SAR captured data of a portion of northeastern North Dakota straddling Grand Forks and Walsh counties. The image shows forests and wetlands on the banks of the Forest River passing through the centre of the frame from west to east and farmland to the north and south.
The dark agricultural plots show fallow fields, while the lighter colours represent the presence of pasture or crops, such as soybean and corn. Circular patterns indicate the use of centre-pivot irrigation.
The images demonstrate how the L-band SAR can discern what type of land cover — low-lying vegetation, trees, and human structures — is present in each area. This capability is vital both for monitoring the gain and loss of forest and wetland ecosystems, as well as for tracking the progress of crops through growing seasons around the world.
“These initial images are just a preview of the hard-hitting science that NISAR will produce — data and insights that will enable scientists to study Earth’s changing land and ice surfaces in unprecedented detail while equipping decision-makers to respond to natural disasters and other challenges,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington. “They are also a testament to the years of hard work of hundreds of scientists and engineers from both sides of the world to build an observatory with the most advanced radar system ever launched by NASA and ISRO.”
The L-band system uses a 10-inch (25-centimeter) wavelength that enables its signal to penetrate forest canopies and measure soil moisture and motion of ice surfaces and land down to fractions of an inch, which is a key measurement in understanding how the land surface moves before, during, and after earthquakes, volcanic eruptions, and landslides.
The preliminary L-band images are an example of what the mission team will be able to produce when the science phase begins in November.
The satellite was raised into its operational 464-mile (747-kilometer) orbit in mid-September.
The NISAR mission also includes an S-band radar, provided by ISRO’s Space Applications Centre, that uses a 4-inch (10-centimeter) microwave signal that is more sensitive to small vegetation, making it effective at monitoring certain types of agriculture and grassland ecosystems.
The spacecraft is the first to carry both L- and S-band radars. The satellite will monitor Earth’s land and ice surfaces twice every 12 days, collecting data using the spacecraft’s drum-shaped antenna reflector, which measures 39 feet (12 meters) wide — the largest NASA has ever sent into space.
The NISAR mission is a partnership between NASA and ISRO spanning years of technical and programmatic collaboration. The successful launch and deployment of NISAR builds on a strong heritage of cooperation between the United States and India in space.
The Space Applications Centre provided the mission’s S-band SAR. The U R Rao Satellite Centre provided the spacecraft bus. The launch vehicle was provided by Vikram Sarabhai Space Centre, and launch services were through Satish Dhawan Space Centre.
Key operations, including boom and radar antenna reflector deployment, are now being executed and monitored by the ISRO Telemetry, Tracking and Command Network’s global system of ground stations.
Managed by Caltech in Pasadena, NASA JPL leads the U.S. component of the project. In addition to the L-band SAR, reflector, and boom, JPL also provided the high-rate communication subsystem for science data, a solid-state data recorder, and payload data subsystem. NASA’s Goddard Space Flight Centre in Greenbelt, Maryland, manages the Near Space Network, which receives NISAR’s L-band data.
About NISAR
The NISAR (NASA-ISRO Synthetic Aperture Radar) mission successfully launched on July 30, 2025, and has since completed its initial post-launch assessments and antenna deployment, with engineers confirming it is on schedule to begin science operations later this year.
The satellite has successfully deployed its L-band and S-band radar payloads and is now transmitting its first radar images of Earth’s surface. The mission aims to provide unprecedented detail on Earth’s land and ice surfaces to track changes related to climate change, aiding in disaster prediction and management, agricultural planning, and infrastructure monitoring.
Key Updates Since Launch
Successful Launch & Orbit:
The satellite was successfully launched on a GSLV-F16 rocket and placed into a precise Sun Synchronous Polar Orbit.
Antenna Deployment:
A major milestone was reached on August 15, 2025, with the successful deployment of the satellite’s 12-meter (39-foot) radar antenna reflector.
Payload Power on
Engineers powered on the L-band and S-band synthetic aperture radar (SAR) payloads, which are crucial for the mission’s ability to track fine movements on the Earth’s surface.
First Images:
As of late September 2025, NISAR has transmitted its first radar images of Earth, showcasing the detailed information it can provide.
Mission Objectives and Capabilities
Dual-Frequency Radar:
NISAR is the first satellite to combine L-band and S-band radar systems, providing complementary data on Earth’s surface.
Earth Surface Monitoring:
The mission will monitor changes in land and ice surfaces, including forest cover, wetlands, ice sheets, and snowpack.
Disaster Management:
Data from NISAR will help communities with disaster response, flood risk assessment, and damage assessment after events like fires.
Agriculture and Land Management:
The satellite’s soil moisture products will support agricultural planning, crop production estimates, and drought monitoring.
