NISAR satellite deploys 12-metre diameter antenna, enters science phase

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NASA-ISRO Synthetic Aperture Radar (NISAR) satellite launched onboard GSLV-F16 on July 30 this year successfully deployed 12-metre diameter antenna reflector and entered science phase, ISRO said on Friday.

The antenna plays a key role for both ISRO's S-Band and NASA's L-Band Synthetic Aperture Radar (SAR) payload, it said.

"The first image of S-Band SAR acquired on August 19, 2025, captures the fertile Godavari River Delta in Andhra Pradesh, India. Various vegetation classes like mangroves, agriculture, arecanut plantations, aquaculture fields, etc. are clearly seen in the image. The image highlights NISAR's S-Band SAR ability to map river deltas and agricultural landscapes with precision," ISRO said in a statement.

On the 100th day of NISAR in orbit, the S-SAR images were released to the public by the Chairman, ISRO. With this, the commencement of the science phase has also been announced, it said.

The antenna was launched in a stowed condition on a 9-metre-long boom, which was tucked close to the satellite. The antenna and the boom were developed by NASA, the statement added.

"The unfolding of the joints of the boom commenced on August 9, 2025, and was carried out over a period of five days (Wrist, Shoulder, Elbow and Root deployments). The reflector assembly mounted on the end of the boom was deployed successfully on August 15, 2025, and the performance of the antenna systems is satisfactory," the statement said.

According to ISRO, the entire operations were carried out from the ISRO Telemetry Tracking and Command Network (ISTRAC) with the support of JPL/NASA.

The space agency said that since the first acquisition on August 19, 2025, NISAR S-Band SAR has been regularly imaging the 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 other locations in India for image calibration.

"Data acquired over Amazon rainforests were also used for calibration of spacecraft pointing and images. Based on this, payload data acquisition parameters were fine-tuned, resulting in high-quality images," it said.

ISRO said initial analysis by scientists and engineers has revealed the potential of S-Band SAR data for various targeted science and application areas, including agriculture, forestry, geosciences, hydrology, polar/Himalayan ice and snow, and oceanic studies.