NISAR: US-India Satellite to Map Earth's Surface in Unprecedented Detail
- NISAR is a joint mission between NASA and ISRO, scheduled to launch in 2025.
- The satellite uses dual-frequency radar (L-band and S-band) to see through clouds and vegetation.
- It will map the entire Earth's land and ice surfaces every 12 days, tracking changes like earthquakes, landslides, and glacier movement.
A powerful new satellite jointly developed by the United States and India is set to transform how scientists observe our planet. Named NISAR (NASA-ISRO Synthetic Aperture Radar), the spacecraft will scan nearly all of Earth's land and ice surfaces every 12 days, providing data that is both more frequent and more detailed than current missions.
What Makes NISAR Different?
Unlike traditional optical satellites that rely on sunlight and clear skies, NISAR uses Synthetic Aperture Radar (SAR) technology. This allows it to take high-resolution images of the Earth's surface day and night, regardless of cloud cover. The satellite carries two radar systems: an L-band radar provided by NASA and an S-band radar built by ISRO. This dual-frequency capability is a first for a global mapping mission.
By comparing images taken over the same area at different times, scientists can detect movements as small as a few millimetres. This makes NISAR exceptionally sensitive to ground deformation caused by earthquakes, volcanic activity, and landslides.
Monitoring Climate and Natural Hazards
NISAR's primary mission is to observe changes in Earth's ecosystems, ice sheets, and solid surface. It will track the melting of glaciers and ice sheets in Greenland and Antarctica, providing critical data for sea-level rise projections. The satellite will also monitor the health of forests and agricultural lands, helping assess carbon storage and water use.
For disaster management, NISAR's rapid mapping cycles will be invaluable. In the event of an earthquake or flood, the satellite can provide before-and-after comparisons within days. Indian agencies plan to use this data for agricultural monitoring, groundwater management, and disaster response.
A Partnership Decades in the Making
The mission is a landmark collaboration between NASA and the Indian Space Research Organisation (ISRO). Work on NISAR began in 2014, with both agencies contributing key components. NASA is providing the L-band radar, the high-rate communication system, and the radar reflector antenna. ISRO is supplying the S-band radar, the spacecraft bus, and launch services.
The satellite will be launched from the Satish Dhawan Space Centre in Sriharikota, India, aboard an ISRO Geosynchronous Satellite Launch Vehicle (GSLV). The launch window is expected in late 2025, after years of testing and integration.
What Happens Next
Once in orbit at an altitude of about 750 kilometres, NISAR will begin a three-year primary mission. Scientists worldwide will have open access to the data, which is expected to produce one of the most comprehensive records of Earth's changing surface ever created. The mission is designed to answer fundamental questions about how our planet's land, ice, and ecosystems are responding to a changing climate.