NISAR: NASA-ISRO Satellite to Map Earth's Surface in Unprecedented Detail

A New Eye in the Sky

The NASA-ISRO Synthetic Aperture Radar, or NISAR, is set to become one of the most powerful Earth-observation satellites ever built. Developed jointly by the American and Indian space agencies, it will scan nearly the entire planet's land and ice surfaces twice every 12 days.

NISAR carries two radar systems — an L-band radar from NASA and an S-band radar from ISRO. Together, they can see through clouds and darkness, capturing images day and night. This capability is critical for monitoring regions that are frequently cloud-covered, such as tropical forests and the Himalayas.

What It Will Track

The mission's primary goals are to measure changes in Earth's ecosystems, ice sheets, and land surfaces. Scientists expect to track deforestation, wetland loss, and the health of agricultural crops. The radar can detect movements as small as a few centimetres, making it ideal for monitoring earthquakes, landslides, and volcanic activity.

NISAR will also monitor the melting of glaciers and ice sheets in Greenland and Antarctica. Data from the mission could help improve models of sea-level rise. Officials have said the satellite will produce an unprecedented volume of data — about 85 terabytes per day.

India's Role

ISRO is providing the spacecraft bus and the S-band radar. The satellite will be launched from the Satish Dhawan Space Centre in Sriharikota, India, aboard a Geosynchronous Satellite Launch Vehicle (GSLV). The mission is expected to launch in 2024, after several delays.

For India, NISAR offers a chance to study the Himalayan region more closely. The satellite will track ground deformation and glacier movement in the mountain range, which is prone to earthquakes and glacial lake outburst floods. Indian scientists will have direct access to the data for research and disaster management.

Collaboration and Data Sharing

NISAR is a rare example of a large-scale, equal partnership between NASA and ISRO. Both agencies share the cost, the technology, and the data. The data will be made freely available to the public and scientific community worldwide, a policy that sets it apart from many other Earth-observation missions.

Experts have pointed out that the mission's success depends on managing the enormous data flow and ensuring the radar systems work in tandem. Engineers have spent years testing the instruments to avoid interference between the two radars.

The satellite is designed for a three-year mission, but its orbit and fuel could allow it to operate longer. What happens after that will depend on the health of its systems and the priorities of the two space agencies.