Data from the NISAR mission will deepen our understanding of phenomena like earthquakes, volcanic activity, and landslides, as well as infrastructure impacts. Although Earth’s surface constantly shifts, much of this movement often goes unnoticed. Researchers have tracked ground shifts linked to volcanoes, earthquakes, landslides, and similar events through satellites and ground instruments. However, the upcoming NASA-ISRO NISAR satellite will enhance our knowledge further, potentially aiding in disaster readiness and recovery for both natural and human-caused events.

Set to monitor nearly every land and ice-covered surface on Earth twice every 12 days, NISAR (NASA-ISRO Synthetic Aperture Radar) will provide a clearer picture of Earth's surface dynamics over time. "This kind of systematic observation lets us see Earth’s surface movement globally," said Cathleen Jones, NISAR applications lead at NASA’s Jet Propulsion Laboratory (JPL) in Southern California.

In combination with other data sources, NISAR's measurements will improve understanding of how Earth's surface shifts horizontally and vertically. This information will offer valuable insights into Earth’s crust mechanics and regions prone to earthquakes and volcanic eruptions. It could even indicate if a levee section is damaged or if a hillside is beginning to slip.

Expected to launch from India in early 2025, NISAR will detect minuscule surface changes down to fractions of an inch. Besides observing shifts on Earth’s surface, it will track the movement of ice sheets, glaciers, and sea ice, along with mapping vegetation changes.

This precision is made possible by two radar systems: a long-wavelength L-band radar from JPL and an S-band radar from ISRO. NISAR is the first satellite to combine both. These radar systems operate day and night and can see through clouds, allowing data collection even in challenging weather. The L-band radar can even penetrate dense vegetation, making it especially useful for tracking movement around volcanoes or obscured fault lines.

"The NISAR satellite won't predict earthquake timing but will reveal which global regions are more susceptible to significant quakes," explained Mark Simons, the U.S. lead for solid Earth science on the mission. Its data will show which parts of a fault slip gradually without quakes and which areas are locked and could slip suddenly. In well-monitored areas like California, NISAR can help researchers focus on regions with earthquake potential. In less monitored areas, it may reveal new earthquake-prone zones. Post-quake, NISAR data will shed light on how the faults shifted.

ISRO’s Sreejith K M highlighted the mission's importance for the Himalayan plate boundary, known for past large quakes. NISAR will provide unprecedented insight into the region’s seismic hazards.

For volcano researchers, surface movement data from NISAR can signal magma shifts below the Earth, which may foreshadow eruptions. The satellite will help reveal the reasons behind volcano deformation and whether movement might indicate an upcoming eruption.

For infrastructure such as levees, aqueducts, and dams, NISAR’s continuous measurements will establish a baseline over time. This enables resource managers to identify and focus on changes, rather than routinely inspecting entire structures. “Instead of inspecting an entire aqueduct every five years, you can target problem areas,” said Jones. After events like earthquakes, NISAR data can confirm if a dam is unaffected or point out damaged areas. For instance, a major earthquake in San Francisco could destabilize levees in the Sacramento-San Joaquin River Delta, where traditional inspection would require extensive resources. "NISAR can survey them from space, flagging only the altered areas," saving time and repair costs, according to Jones.

The NISAR mission marks a collaborative milestone for NASA and ISRO as they co-develop hardware for an Earth-observing mission. Managed by Caltech, JPL leads the U.S. contribution, supplying the L-band SAR, radar reflector, deployable boom, data communication systems, GPS receivers, and payload data subsystem. ISRO’s U R Rao Satellite Centre in Bengaluru is overseeing the spacecraft bus, launch vehicle, launch services, and mission operations, while its Space Applications Centre in Ahmedabad provides the S-band SAR electronics.