NISAR: The joint Earth-Observing mission of NASA and ISRO

NASA and ISRO are collaborating on developing a satellite called NISAR, which will detect movements of the planet’s surface as small as 0.4 inches over areas about half the size of a tennis court.

The satellite will be launched in 2022 from the Satish Dhawan Space Center in Sriharikota, India, into a near-polar orbit and will scan the globe every 12 days over the course of its three-year mission of imaging the Earth’s land, ice sheets and sea ice to give an “unprecedented” view of the planet.

What is NISAR?

It’s an SUV-sized satellite that is being jointly developed by the space agencies of the US and India. The partnership agreement was signed between NASA and ISRO in September 2014, according to which NASA will provide one of the radars for the satellite, a high-rate communication subsystem for science data, GPS receivers and a payload data subsystem. ISRO, on the other hand, will provide the spacecraft bus, the second type of radar (called the S-band radar), the launch vehicle and associated launch services.

Significantly, NISAR will be equipped with the largest reflector antenna ever launched by NASA and its primary goals include tracking subtle changes in the Earth’s surface, spotting warning signs of imminent volcanic eruptions, helping to monitor groundwater supplies and tracking the rate at which ice sheets are melting.

The name NISAR is short for NASA-ISRO-SAR. SAR here refers to the synthetic aperture radar that NASA will use to measure changes in the surface of the Earth. Essentially, SAR refers to a technique for producing high-resolution images. Because of the precision, the radar can penetrate clouds and darkness, which means that it can collect data day and night in any weather.

During the course of three years, the images will allow scientists to track changes in croplands, hazard sites and will help them to monitor crises such as volcanic eruptions. “The images will be detailed enough to show local changes and broad enough to measure regional trends. 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 has said.

The images will be able to capture changes in the Earth caused by certain activities. For instance, drawing drinking water from an underground aquifer can leave signs on the surface. If too much of it is drawn out, the ground begins to sink, which is what scientists believe the images will be able to show them.

“NISAR is an all-weather satellite that’s going to give us an unprecedented ability to look at how Earth’s surface is changing,” Paul Rosen, NISAR project scientist at JPL was quoted as saying in a NASA statement.