NISAR Mission enters science phase after antenna deployment

The Indo-US joint NISAR Mission has officially entered its science phase following the successful deployment of its 12-metre radar antenna, marking a major milestone in the world’s first dual-frequency radar imaging satellite developed by ISRO and NASA. ISRO announced that after the NISAR satellite—launched aboard GSLV-F16 on July 30 into a 747 km circular polar sun-synchronous orbit—completed its commissioning phase, the crucial 12-metre antenna reflector was fully deployed. The reflector, mounted on a 9-metre boom built by NASA, supports both ISRO’s S-Band and NASA’s L-Band Synthetic Aperture Radar (SAR) payloads. The complex deployment process began on August 9, 2025, and was carried out over five days, involving the sequential unfolding of the boom’s joints—wrist, shoulder, elbow and root. The reflector assembly itself was deployed on August 15, with all systems performing satisfactorily. These operations were executed by ISTRAC in coordination with NASA’s Jet Propulsion Laboratory. Following the Launch, Deployment and Commissioning phases, the mission has now transitioned into the Science Phase, which will continue through the satellite’s five-year lifespan. During this stage, the satellite’s science orbit will be maintained with regular manoeuvres, while extensive calibration and validation activities take place. Observation plans for both radar bands are being coordinated by ISRO and JPL. Since its first acquisition on August 19, 2025, NISAR’s S-Band SAR has been capturing high-resolution images over India and global calibration sites. Corner reflectors deployed near Ahmedabad and other locations have aided image calibration. Data captured over the Amazon rainforest has helped fine-tune spacecraft pointing and imaging parameters, resulting in improved image quality. The first S-Band SAR image—released on the satellite’s 100th day in orbit—showcases the Godavari River Delta in Andhra Pradesh, clearly detailing mangroves, agricultural fields, aquaculture zones and plantation areas. Early analysis highlights NISAR’s powerful capability to map river deltas, wetlands, forests and agricultural landscapes with precision. @@@