Nellore: S-Band Synthetic Aperture Radar (SAR) payload built at the Space Applications Centre (SAC), Ahmedabad, of the Indian Space Research Organisation has been shipped to the Jet Propulsion Laboratory (JPL), Pasadena, California. It will be integrated with the L-Band SAR Payload of JPL for the Nasa-Isro Synthetic Aperture Radar (Nisar) mission which is scheduled to launch in late 2021.
The mission will have a minimum lifetime of three years. The payload was flagged off by Isro Chairman Dr K. Sivan recently in the virtual mode.
Isro said the Nisar satellite will provide a detailed view of the Earth to observe and measure some of the planet’s most complex processes, including ecosystem disturbances, ice-sheet collapse, and natural hazards. As with Nasa missions, the Nisar data will be openly available, free of charge.
The mission will also be capable of supporting disaster response through expedited event-driven downlinking, processing, and delivery of relevant data.
Nisar will utilise two synthetic aperture radars (SAR) operating at different frequencies to study the Earth. Nasa will provide the L-band SAR and Isro the S-band SAR.
The L-band equipment will provide all-weather, day and night imaging of nearly the entire land and ice masses of the Earth and the S-band instrument will provide additional coverage of India and parts of the polar regions.
Most areas will be imaged four to six times a month, with exact repeat of the orbits at 12-day intervals. Nisar’s imaging resolution will be 3-50 metres, depending upon the operating mode.
The repeat orbit images can be used to identify and track the subtle movement of the Earth’s land using interferometric synthetic aperture radar (InSAR) that can detect small-scale surface deformation before it is visible to the eye.
Nisar will be the first radar of its kind in space to systematically map the Earth using two different frequencies (L-band and S-band) to measure changes in the planet's surface of less than a centimeter across.