NISAR earth observation satellite enters final science operations phase

The NASA ISRO Synthetic Aperture Radar (NISAR) satellite, launched in July, has entered the science phase, the ISRO announced on Friday (November 28, 2025).

The earth observation satellite provides all-weather, day-and-night data, which have a wide range of applications. It is the first satellite jointly developed by the Indian Space Research Organisation (ISRO) and the U.S.’s National Aeronautics and Space Administration (NASA).

The NISAR mission is broadly classified into different phases – launch, deployment, commissioning and science phases. The final science operations phase begins at the end of commissioning and extends till the end of NISAR’s five-year mission life.

“During this phase, the science orbit will be maintained via regular manoeuvres, scheduled to avoid or minimise conflicts with science observations. Extensive calibration and validation activities will take place,” the ISRO had said earlier.

Following the successful launch of the satellite on July 30 from the Satish Dhawan Space Centre in Sriharikota, the 12-metre diameter antenna reflector was successfully deployed.

The 12-meter diameter 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 was developed by NASA. The unfolding of the joints of the boom commenced on August 9, and was carried out over a period of five days.

The reflector assembly mounted on the end of the boom was deployed successfully on August 15.

“Since the first acquisition on August 19, NISAR S-Band SAR has been regularly imaging Indian landmass and global calibration-validation sites in various payload operating configurations. Reference targets such as corner reflectors were deployed around Ahmedabad, Gujarat, 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,” the ISRO said.

It added that based on this, payload data acquisition parameters were fine-tuned resulting in high-quality images.

“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,” it added.