Why in news?
On 31 July 2025, India successfully launched the NASA–ISRO Synthetic Aperture Radar (NISAR) satellite aboard a Geosynchronous Satellite Launch Vehicle (GSLV‑F16) from Sriharikota. This is the first joint Earth‑observation mission between the Indian Space Research Organisation and NASA.
What is NISAR?
NISAR is an Earth‑imaging satellite equipped with two radar systems: an L‑band radar supplied by NASA and an S‑band radar contributed by ISRO. This dual‑frequency synthetic aperture radar can measure changes in Earth’s surface—including land deformation, ice sheet movements, vegetation and soil moisture—with centimetre‑level precision.
Key mission details
- The satellite will operate in a sun‑synchronous polar orbit about 747 kilometres above Earth. A sun‑synchronous orbit ensures consistent lighting conditions, which is essential for comparing images over time.
- Its mission life is planned for five years (2025–2030), with a revisit cycle of about 12 days. This means it will scan the same area every 12 days to detect changes.
- The satellite has a wide swath of around 240 kilometres, enabling it to cover large areas quickly while still providing high‑resolution data.
- NASA contributed the L‑band radar, a deployable 12‑metre reflector antenna, GPS receivers and data storage, while ISRO built the S‑band radar, satellite bus, launch vehicle and ground systems.
Objectives and applications
- NISAR will monitor natural hazards such as earthquakes, landslides, floods and volcanic eruptions by measuring tiny movements of Earth’s surface.
- It will track changes in forests, glaciers, wetlands and soil moisture, aiding climate studies and resource management.
- The data will support agriculture by providing information on crop growth and soil conditions, helping farmers plan irrigation and fertiliser use.
- Because the mission’s data policy encourages open access, researchers worldwide can use NISAR data for scientific and societal applications.
Significance
- NISAR is a hallmark of Indo‑US space collaboration and demonstrates how international partnerships can advance Earth science.
- The mission enhances India’s position in high‑end space technology and shifts focus from utility‑oriented to knowledge‑driven space applications.
- Accurate Earth‑observation data will contribute to early‑warning systems, climate resilience and evidence‑based policymaking.
Conclusion
The successful launch of NISAR strengthens India’s scientific capabilities and global cooperation in monitoring our changing planet. Its data will support a wide range of applications, from disaster management to climate action.