NEW DELHI: Seven years after India and the US signed an agreement in 2014 to jointly develop the world’s first earth observation satellite with two different radars that can produce very high-resolution images, Indian Space Research Organisation (Isro) has achieved a key milestone by making the S-band Synthetic Aperture Radar (SAR) and shipping it to Nasa for integration with the L-band payload being developed by the US agency.
Once the integration of the two radars is done, Nasa will send them to India where other parts of the Nasa-Isro SAR (NISAR) satellite will be built. Isro will then use its GSLV Mk-II rocket to launch NISAR from the Sriharikota launchpad.
The satellite will be the world’s first-of-its-kind that will operate on two radio frequencies with capability to collect data day and night and in all weather, including during cloudy days. “Its data can help people worldwide better manage natural resources and hazards like earthquakes, tsunamis, volcanoes and landslides, as well as provide information to better understand the effects and pace of climate change. It will also add to our understanding of the planet’s hard outer layer (crust),” according to Nasa. Besides supporting a host of applications, NISAR, which will be able to “measure changes in the Earth’s surface less than a centimeter across”, will also help measure and study dynamic surfaces, ice masses like Himalayan glaciers, sea level rise and groundwater level.
On March 4, the Isro chairman flagged off the S-band SAR from the agency’s Ahmedabad-based Space Applications Centre through virtual mode to Nasa’s Jet Propulsion Laboratory in California’s Pasadena. Isro chairman K Sivan told TOI: “Nasa will integrate our S-band and their L-band radars and sent the integrated module back to India in the first quarter of next year and the complete satellite will be ready by 2022-end. We will then target to launch NISAR in early 2023.”
NISAR will have an imaging swath — the width of the strip of data collected along the length of the orbit track — greater than 240 km and will therefore observe Earth’s land and ice-covered surfaces globally with 12-day regularity.
Over the course of multiple orbits, the radar images will allow users to track changes in crop-lands and hazard sites, as well as monitor ongoing crises such as volcanic eruptions. “As the mission continues for years, the data will allow for better understanding of the causes and consequences of land surface changes, increasing our ability to manage resources and prepare for and cope with global change,” Nasa said.
NISAR, which will weigh 2,800 kg, is estimated to be the world’s most expensive imaging satellite. The total cost of the project includes Isro’s work share cost of about Rs 788 crore and about $808 million (nearly Rs 5,890 cr) of Nasa. As per the partnership, Nasa has to provided the satellite mission’s L-band SAR, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem while Isro will make arrangement for the spacecraft bus, S-band radar, the launch vehicle (GSLV) and associated launch services for the mission.
Nasa administrator Charles Bolden and the then Isro chairman K Radhakrishnan had signed the NISAR partnership agreement in Toronto on September 30, 2014. Since then, both space agencies have been working hard on this sophisticated satellite mission.