Eye on Earth

The NASA-ISRO Synthetic Aperture Radar, set for an early 2024 launch, will help predict natural disasters like the Joshimath sinking

- ABHINAV SINGH

THEY WERE ON each other’s radar, their wavelengths matched and it was a coming together like no other. No, romance was not in the air, but a rocket soon would be.

The rocket—the Indian Space Research Organisation’s Geosynchronous Satellite Launch Vehicle Mark II (GSLV-Mk II)—will carry the NASA-ISRO Synthetic Aperture Radar (NISAR). The launch date is set for early next year. The GSLVMk II will unload NISAR at an orbit 747km above Earth.

NISAR, to put it simply, will perhaps be the fanciest, high-tech version of a camera out there. Only, it will produce fine-resolution images of the Earth’s land and ice surfaces, helping measure the changing ecosystem and provide data about natural hazards, sea level rise and groundwater level. NISAR will be on a three-year mission, observing the planet every 12 days, morning and evening, come rain or shine. This is the first-ever collaboration between NASA and ISRO on an Earth-observing mission. And, NISAR is likely to be the most expensive satellite—$1.5 billion. That is probably because its payload will be the most advanced radar system ever launched.

A rocket’s payload can be a satellite, a space probe or a spacecraft carrying humans. NISAR’s payload is a satellite, consisting of two radar systems—the 24cm-wavelength L-band built by NASA’s Jet Propulsion Laboratory (JPL) in South California, and the 10cm-wavelength S-band built by ISRO. The S-band was shipped to JPL in March 2021. The two bands were integrated and tests were done to check if they work well together. And, on March 6 this year, the payload was flown in to ISRO’s U.R. Rao Satellite Centre in Bengaluru.