Radar-based NASA-ISRO satellite to measure changes in Earth

Ritu Jha-

“It’s not just for the U.S. and India, but for the entire globe.”

That was S Somanath, chairman of the Indian Space Research Organization (ISRO), speaking at the flagging off of the NASA-ISRO Synthetic Aperture Radar (NISAR) at the Jet Propulsion Laboratory (JPL) in Pasadena, California, Feb. 3.

The joint effort at building a satellite aims to understand the causes and consequences of land surface changes. NISAR is to be launched early next year.

Somanath, JPL Director Laurie Leshin, other officials and dignitaries from NASA headquarters and India, and members of the media learned about NISAR’s advanced radar instruments, which are in a clean room at NASA’s (JPL) facility, before it is sent to India at the end of the month.

Somanath told indica that the idea for the satellite came out of ISRO’s experience with imaging.

“We [at ISRO] already have certain imaging satellites up there, all working in single band,” he said, adding that using two of them – the S-band radar built by India, and the L-band built in the U.S – there could be a lot more data generated, and greater detail of physical formations seen.

He said the antenna used was large, being 12 meters in diameter, and provided high-resolution images. and because of its orbital placement it has a very high repetition of observation and whole global coverage will give a huge amount of data.

“Data is going to the ground station on both the Indian side and U.S. side, and we will make sure this data is going to be at the disposal of both sides,” Somanath said. “This is not a commercial mission for the time being. It’s a mission for science to understand the world better.

During the press conference, he said that while ISRO has done well in the space sector, that was not to the scale seen in the U.S.

Thanking JPL for its consistent support, Somanath said, “The Chandrayaan 1 and 2 and Mission to Mass would not have been possible without you. “I tell you, we wouldn’t have been successful.”

Asked if NISAR would also address issues involving climate change, JPL Director Leshin told indica this mission indeed addressed the matter. These included changes in flora, in ice sheet thickness, and how forests react to climate change.

“Yes, that [climate change] is an important part of NISAR,” she said. “But also, natural hazards like earthquakes and volcanoes. We are trying to understand the movement of the Earth. Certainly, after such events take place, we will be able to see changes. The question is, can we track changes even before such natural disasters happen. So this is a huge opportunity.”

Later, Somanath told indica that NISAR could help India understand the nuances of water management at a time when more glaciers are melting. India relies a lot on glaciers for its supply of water.

NISAR is expected to ensure unprecedented, continual, high-resolution monitoring of geological faults all over the world.

Leshin said it would also gauge soil moisture and water trapped in the top layer of the Earth. The dryness of the ground could show what are the most vulnerable areas to fires.

Prior to attending the event, Somanath joined Deputy Chief of Mission at the Indian Embassy Sripriya Ranganathan and NASA officials to tour the High Bay 2 clean room, where engineers and technicians did the final electrical testing of the science instrument payload.

Outside the facility, in front of a scale model of the NISAR satellite, NASA’s NISAR Project Manager Phil Barela and ISRO’s NISAR Project Director CV Shrikant ceremonially broke fresh coconuts. The Indian tradition marks auspicious occasions and the hope of an untroubled future. Leshin presented the ISRO delegation with a jar of JPL’s lucky peanuts.

NISAR is to observe Earth’s land and ice-covered surfaces globally with 12-day regularity on ascending and descending passes, sampling Earth on average every six days for a baseline three-year mission.

James E Graf, director for earth science and technology at JPL, told indica though the agreement to work jointly was signed in 2014, the teams were already collaborating on the issue earlier.

The deal was signed in Toronto by NASA Administrator Charles Bolden and K. Radhakrishnan, the chairman of the Indian Space Research Organisation.

According to NASA, NISAR’s Synthetic Aperture Radar mission could determine Earth changes in three disciplines: ecosystems (vegetation and the carbon cycle), deformation (solid Earth studies), and cryospheric sciences (related to things that affect the climate and their effects on sea level). Based on earlier studies, they teamed up with ISRO in 2012, leading ultimately to the joint space mission that brought together the L-band and S-band SAR systems.

Describing NISAR as a demanding and technically challenging program, Graf said, “You have to be sure it’s done right.”


[Photo courtesy:indica]


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