ISRO and NASA to Launch Joint Earth Observation Satellite NISAR on July 30

28 July, 2025

The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite is scheduled for launch on July 30 from Sriharikota. The landmark joint mission, a first between the two space agencies, will use dual-frequency L-band and S-band radar to monitor Earth's surface with unprecedented detail. Weighing 2,392 kg, NISAR will track changes in ecosystems, ice sheets, and the planet's crust, providing crucial open-access data for climate change research, disaster management, and resource monitoring, with data made freely available within days of observation.

Unpacked:

What are the main scientific goals of the NISAR mission?

NISAR aims to monitor dynamic changes on Earth's surface, including land deformation (such as tectonic shifts, subsidence, and volcanic uplift), changes in ecosystems, ice sheets, and the planet's crust. Its precise radar imaging will help improve hazard models, support climate change research, disaster management, and resource monitoring by detecting subtle ground movements and surface changes.

How does NISAR's dual-frequency radar improve data quality compared to previous satellites?

NISAR uses both L-band and S-band synthetic aperture radars, allowing it to monitor the Earth's surface through clouds and vegetation. The L-band penetrates thicker vegetation and is ideal for landscape and forest monitoring, while the S-band is suited for soil moisture and polar regions. This dual-frequency approach enables more detailed, consistent, and reliable surface observations than single-frequency systems.

What roles did NASA and ISRO each play in building and launching NISAR?

NASA provided the L-band radar, the 12-meter deployable antenna, the instrument structure, data recorder, GPS, and Ka-band telecom system. ISRO contributed the spacecraft, S-band radar electronics, and the launch vehicle (GSLV-II). The mission is a collaboration, with NASA and ISRO sharing responsibility for science operations and mission management.

How frequently will NISAR collect and release data about Earth's surface changes?

NISAR will image any land surface twice in each 12-day cycle (ascending and descending passes), ensuring frequent and consistent monitoring. The processed data will be made freely available within days of observation, supporting timely research and response for climate, disaster, and resource management applications.