The Indian space agency on 28th November 2025 declared the beginning of the science phase of the NASA ISRO Synthetic Aperture Radar (NISAR) satellite. At about $1.5 billion cost, the NISAR, a US-India joint project is the world’s costliest earth observation satellite built and orbited till date. The satellite was launched on 30th July, 2025 by the Indian rocket GSLV-F16 from the Indian rocket port in Sriharikota.
According to the Indian Space Research Organisation (ISRO), NISAR’s 12 metre antenna reflector has been successfully deployed. The antenna reflector plays a key role for both ISRO’s S-Band and NASA’s L-Band Synthetic Aperture Radar (SAR) payload. The antenna was launched in a stowed condition on a 9m long boom, which was tucked close to the satellite. The antenna and the 9m boom were developed by NASA.
ISRO said the unfolding of the joints of the boom commenced on 09th August 09 2025 and was carried out over a period of five days – with Wrist, Shoulder, Elbow and Root deployments. The reflector assembly mounted on the end of the boom was deployed successfully on 15th August 2025 and the performance of the antenna systems is satisfactory.
The entire operations were carried out from ISRO Telemetry Tracking and Command Network (ISTRAC), with the support of Jet Propulsion Laboratory (JPL), NASA.
According to ISRO, the first image from NISAR was received on August 19, 2025 and since then NISAR S-Band SAR is regularly imaging over Indian Landmass and Global Calibration-Validation sites in various payload operating configurations.
Reference targets such as with corner reflector antennas were deployed around Indian city Ahmedabad and a few more locations in India for calibration of the images. Data acquired over Amazon rainforests were also used for calibration of spacecraft pointing and images, said the Indian space agency.
Based on this, payload data acquisition parameters were fine tuned resulting in high quality images.
Good Potential for S-Band and SAR Data
Initial analysis by scientists and engineers revealed the potential of S-Band SAR data for various targeted science and application areas like agriculture, forestry, geo-sciences, hydrology, Polar/Himalayan ice/snow and oceanic studies.
The first image of S-band SAR captured the fertile Godavari River Delta in the Indian state of Andhra Pradesh. Various vegetation classes like mangroves, farms, arecanut plantations, aquaculture fields and others can be seen clearly in the image. The image highlights NISAR’s S-Band SAR ability to map river deltas and agricultural landscapes with precision.
On the 100th day of NISAR in-orbit, the S-SAR images were released to the public by Dr. V.Narayanan, Chairman, ISRO/ Secretary, Department of Space, Government of India.
The NISAR mission was divided into different phases viz.,
-launch phase (being carried in the GSLV rocket);
-deployment phase (deploying the 12m reflector in-orbit 9m away from the satellite by a complex multistage deployable boom designed and developed by JPL/NASA);
-commissioning phase (the first 90 days after launch dedicated to commissioning, or In-Orbit Checkout of the satellite systems) and
-science phase (began at the end of commissioning and extends till end of mission life –5 years-durng which time NISAR will be observing the Earth).
SweepSAR Technology To Observe The Earth
Using SweepSAR technology for the first time, NISAR will observe the Earth with a wide 242 km swath and high spatial resolution, enabling unprecedented insights into changes in ecosystems, ice sheets, land deformation, and more.
The satellite will scan the entire globe and provide all-weather, day and night data at a 12-day interval, enabling a wide range of applications. NISAR can detect even small changes in the Earth’s surface such as ground deformation, ice sheet movement and vegetation dynamics.
Additional Uses of NISAR
Further applications include sea ice classification, ship detection, shoreline monitoring, storm characterization, changes in soil moisture, mapping and monitoring of surface water resources and disaster response, the Indian space agency added.
NISAR will be the first Earth-observing satellite utilising both L-band (25 cm) and S-band (10 cm). NISAR’s two radar signals will react differently to some features on Earth’s surface. By taking advantage of that those differences, it will then produce highly detailed 3D images that should help researchers better understand and predict natural disasters, such as wildfires, volcanic eruptions, earthquakes and landslides.
On 30th September 2014, ISRO and NASA signed an equal partnership to collaborate and launch NISAR.
Reflector Deployment-Image Credit: ISRO
Image Credit: ISRO
Image Credit: NASA/ISRO
