What Is The Science Behind NISAR? Know How NASA-ISRO Project Will Monitor Earth Like Never Before

NISAR, a NASA-ISRO satellite mission launching in 2025, will use radar technology to measure Earth's surface movements, providing insights into tectonic activity, volcanic eruptions, disaster response

An image of NISAR at JPL, in Pasadena.

Source : PTI

NISAR Mission: Imagine being able to watch Earth breathe, capturing each subtle shift in the ground, tracking everything from tectonic rumbles to the slow advance of glaciers. That’s the ambitious goal of NISAR, a satellite mission developed by NASA and the Indian Space Research Organisation (ISRO). Slated to launch in early 2025 from India, the NASA-ISRO Synthetic Aperture Radar, or NISAR, is set to orbit the planet and meticulously measure even the smallest surface movements, down to fractions of an inch. This precision, project scientists explain, will reveal a world in flux, where landscapes move, deform, and sometimes rupture under the forces of nature and human activity.

From earthquake-prone regions to volcanic hotspots, NISAR’s data promises to transform our understanding of Earth's dynamic processes and improve how we prepare for natural and human-caused disasters. The mission’s data will give scientists — and potentially even city planners and disaster response teams — a detailed view of how Earth’s surface changes over time, equipping them to respond to everything from infrastructure damage to looming geological threats.

This is the first time NASA and ISRO have jointly developed satellite hardware for an Earth-observing mission. 

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The Science Behind NISAR

Much of Earth’s surface is constantly moving, yet these motions often go unnoticed by human senses. Scientists have relied on satellite data and ground-based instruments to monitor changes in the land caused by natural forces like tectonic shifts and volcanic activity. In a recent article, scientists involved with the NISAR project explained how the mission is expected to take our understanding to the next level by measuring Earth's surface motion across almost the entire planet, including horizontal and vertical displacements. 

The NISAR mission aims to measure the motion of all the land and ice-covered surfaces of Earth twice every 12 days, giving researchers a better and bigger picture of how the planet's surface changes over time. “This kind of regular observation allows us to look at how Earth’s surface moves across nearly the entire planet,” said Cathleen Jones, NISAR applications lead at the Jet Propulsion Laboratory of NASA.

This level of detail provides crucial insights into tectonic mechanics, helping scientists identify which areas are more prone to natural disasters and even how faults and volcanoes are behaving over time. By observing Earth's movement over months and years, NISAR can reveal patterns that might not be visible from a single measurement.

The NISAR project combines NASA’s expertise in L-band radar technology with ISRO’s S-band radar capabilities. The dual radar systems allow NISAR to capture images day and night, in all weather conditions, and even through dense vegetation. The L-band system, created by JPL, is designed to penetrate vegetation, making it especially useful for tracking changes around volcanoes and faults hidden under forested regions. Meanwhile, ISRO’s S-band radar system complements this with high-resolution imaging that helps to track subtle changes in surface motion, the article cited above explains.

The JPL-managed NASA components include the radar reflector antenna, communication subsystems, and solid-state recorder, all of which will work in tandem with the spacecraft bus, launch vehicle, and operational support provided by ISRO.

How NISAR Data Will Be Used

Monitoring Earthquakes And Fault Lines: NISAR won’t predict earthquakes, but it will help scientists pinpoint areas most susceptible to seismic activity. It will provide insights into how tectonic plates interact and identify fault sections that may pose a risk of sudden movement. This is particularly valuable for areas not currently monitored extensively, allowing researchers to study earthquake-prone zones across the globe. "From the ISRO perspective, we are particularly interested in the Himalayan plate boundary,” said Sreejith KM, ISRO’s solid Earth science lead for NISAR who works at the Space Applications Center in Ahmedabad. He believes the area has been the site of many significant earthquakes, and NISAR’s data will contribute critical information on seismic hazards in the region.

Volcano Monitoring: For volcanologists, surface movement is a crucial indicator of potential eruptions. Magma moving beneath Earth’s crust can cause the surface above to bulge or sink, signalling an impending eruption. With regular observations, NISAR will help scientists monitor these deformations in near real-time, providing valuable data on which volcanic areas are at risk and when an eruption might be likely.

Infrastructure Assessment And Disaster Recovery: Beyond natural disasters, NISAR’s data will be instrumental in monitoring critical infrastructure. It will provide a baseline for normal conditions, helping to identify any sudden changes. Whether it’s an airport runway, a dam, or a levee, knowing the regular state of infrastructure helps pinpoint potential weak spots before they become problematic. “Instead of going out and surveying an entire aqueduct every five years, you can target your surveys to problem areas,” said Jones. In disaster scenarios, such as an earthquake striking the levees of California’s Sacramento-San Joaquin River Delta, NISAR’s capability to assess damage from space could streamline repair efforts, saving time and resources, she said.