NISAR: Most advanced radar tech to deliver unprecedented view of Earth

NISAR, which will feature the most advanced radar system on a NASA science mission, has moved a step closer to its 2024 launch, according to a press release delivered on March 8. 

Short for NASA-ISRO Synthetic Aperture Radar, NISAR will observe almost all Earth's lands and ice surfaces twice every 12 days,  measuring movement in unprecedented fine detail both day and night. 

Significantly, the data obtained by NISAR will help scientists better manage some of Earth's most critical uncertainties, such as melting sea ice, groundwater supply, and natural hazards. It will also add to our understanding of our planet's hard outer layer, called its crust.

NISAR: A first-of-its-kind in space

NISAR's science payload will consist of two radar systems- one built by NASA and the other by the Indian Space Research Organisation (ISRO). It will also have the largest radar antenna of its kind: a drum-shaped wire mesh reflector with a diameter of about 40 feet (12 meters) extending from a 30-foot (9-meter) boom.

NISAR will also be the first such radar in space to routinely survey Earth to assess changes in our planet's surface less than a centimeter across utilizing two separate radar frequencies (L-band and S-band).

Synthetic aperture radar (SAR) creates high-resolution images from a resolution-limited radar system resolution. It needs the radar to travel in a straight line- either on an aircraft or, as with NISAR, orbiting in space.

By surpassing the physical limitations of resolution in space, SAR can produce images and scientific data of a considerably higher caliber than would be achievable with the antenna size alone.

Will NISAR detect earthquakes and volcanoes?

Humanity is now more exposed than ever to natural risks as the surface of the Earth is constantly changing due to both natural and human processes. These alterations, which range from minor crustal tremors to volcanic explosions, will be measured by NISAR.

Human populations are growing in high-risk regions susceptible to landslides, tsunamis, earthquakes, volcanoes, sea level change, and other natural disasters. Already, each year, these dangers result in tens of thousands of fatalities and billions of dollars in damage. 

Understanding these natural hazards and taking measurements at different points in the danger cycle are necessary for better forecasting and mitigation. It is hoped that observations before and after disasters will be provided in short time frames due to NISAR's rapid and global coverage.