New Delhi: In some days, a new satellite that can detect changes on earth’s surface down to the centimetre, in almost real-time and not after the time of day or weather conditions, is set to launch from India’s Satish Dhawan Space Centre near Chennai. Weighing nearly 3 tonnes and boasting a 12-metre radar antenna, the US$ 1.5 billion NISAR satellite will track the ground beneath our feet and the water that flows over and through it in unprecedented detail, providing valuable information for farmers, climate scientists, and natural disaster response teams.
The NISAR satellite, a collaboration between the national space agencies of the United States and India, overcomes these challenges by using synthetic aperture radar technology to capture images of the Earth’s Surface. This technology also gives a satellite its name. NISAR stands for NASA-ISRO SAR.
This SAR technology was invented in 1951 for military use. Rather than using reflected sunlight to passively image the Earth’s surface, SAR satellites work by actively beaming a radar signal toward the surface and detecting the reflected signal. Think of this as using the flash to take a photo in a dark room.
NISAR, scheduled to launch on June 18, will significantly build upon this earlier work. The NISAR satellite has been in development for over a decade and is one of the most expensive Earth-imaging satellites ever built. Data from the satellite will be supplied freely and openly worldwide. It will provide high-resolution images of nearly all land and ice surfaces around the globe, capturing them twice every 12 days.
The NISAR satellite will also be helpful for agricultural applications, with a unique capability to estimate soil moisture levels with high resolution in all weather conditions. This is valuable for farming applications because such data can be used to determine when to irrigate, ensuring healthy vegetation and potentially improving water use efficiency and crop yields. Furthermore, the applications of the NISAR mission will include tracking the flow of the Earth’s ice sheets and glaciers, monitoring coastal erosion, and detecting oil spills. People can expect to see numerous benefits for science and society arising from this highly ambitious satellite mission.
