Why this matters now
NISAR is tested for: announced PM Modi-Obama joint statement 30 Sept 2014; agreement Sept 2014 signed; NASA L-band SAR + ISRO S-band SAR; world’s first dual-frequency SAR satellite; 12 m deployable mesh antenna reflector (largest ever for Earth obs); mass 2800 kg; orbit 747 km SSO; 3-year nominal mission; launch 30 Jul 2025 GSLV-F16 from SHAR; observations: tectonic shifts (earthquakes, volcanoes), glacier + sea-ice melt, biomass + deforestation, soil moisture, wetland inundation; resolution 5-10 m; revisit 12 days; open data; India’s share Rs 1500 crore + ISRO built S-band SAR + bus + launch; US share NASA built L-band SAR + reflector boom assembly ~$1.2 b.
Design highlights
- L-band SAR (NASA JPL): 24 cm wavelength — penetrates vegetation + dry soil; great for biomass, soil moisture.
- S-band SAR (ISRO SAC Ahmedabad): 12 cm wavelength — finer detail; agriculture + surface change.
- 12 m deployable mesh antenna — largest reflector ever for Earth observation. Provides shared aperture for both radars.
- Operates day + night, sees through clouds.
- Polar SSO 747 km, descending dawn-dusk; 12-day repeat.
Science goals
- Cryosphere: map Antarctic + Greenland ice sheet motion; glacier flow; sea ice.
- Tectonics: sub-cm ground deformation — earthquakes, volcanoes, landslides.
- Ecosystems: biomass, deforestation, wetland change.
- Soil moisture + agriculture: root-zone moisture; crop monitoring.
- Sea-level rise + coastal change: inundation mapping.
- Disaster response: flood + earthquake rapid mapping.
Significance
- Largest civilian Earth obs collaboration — ~US$1.5 billion. NASA share dominates due to L-band + reflector.
- India-US Civil Space cooperation — centrepiece. Part of 2014 + 2023 joint commitments.
- Data is fully open within 1-2 days of acquisition — benefits global climate + disaster community.
- Demonstrates ISRO can build space-qualified S-band SAR + integrate large reflector + launch heavy joint missions.
- Sets precedent for future India-US deep space + crewed cooperation (Artemis Accord 2023).
UPSC angle
Know NISAR (NASA-ISRO Synthetic Aperture Radar) — JOINT INDIA-US Earth observation satellite world’s FIRST DUAL-FREQUENCY (L + S BAND) SAR SATELLITE; ANNOUNCED PM MODI-OBAMA joint statement 30 SEPT 2014; agreement Sept 2014; NASA L-BAND SAR (JPL 24 cm wavelength penetrates vegetation + dry soil biomass soil moisture) + ISRO S-BAND SAR (SAC AHMEDABAD 12 cm finer detail agriculture surface change); 12 M DEPLOYABLE MESH ANTENNA REFLECTOR LARGEST EVER FOR EARTH OBS; mass 2800 kg; orbit 747 km SSO descending dawn-dusk; 12-day repeat; 3-year nominal mission; LAUNCH 30 JUL 2025 GSLV-F16 from SHAR; observations TECTONIC SHIFTS earthquakes volcanoes + GLACIER + SEA-ICE MELT + BIOMASS DEFORESTATION + SOIL MOISTURE + WETLAND INUNDATION; resolution 5-10 m; OPEN DATA within 1-2 days; INDIA SHARE Rs 1500 CRORE ISRO built S-band SAR + bus + launch; US SHARE NASA built L-band SAR + reflector boom assembly ~$1.2 b; LARGEST CIVILIAN EARTH OBS COLLABORATION ~US$1.5 BILLION; India-US Civil Space cooperation centrepiece (2014 + 2023 joint commitments); demonstrates ISRO can build space-qualified S-band SAR + integrate large reflector + launch heavy joint missions; precedent for India-US deep space + crewed cooperation ARTEMIS ACCORDS 2023.
Frequently asked questions
What is NISAR?
NASA-ISRO Synthetic Aperture Radar — joint India-US Earth observation satellite. World’s first dual-frequency (L + S band) SAR satellite. Launched 30 July 2025 by GSLV-F16.
What does NISAR observe?
Earth’s solid surface, ice + ecosystem changes. Maps tectonic shifts (mm-cm precision), glacier + sea ice motion, biomass + deforestation, soil moisture, wetland inundation. Revisits the same point every 12 days.
How much did NISAR cost?
~US$1.5 billion — largest civilian Earth observation mission ever. India’s share Rs 1500 crore (ISRO built S-band SAR + bus + launch); US share ~$1.2 b (NASA L-band SAR + reflector).
Why is dual-frequency SAR important?
L-band (24 cm) penetrates vegetation + dry soil — great for biomass + root-zone moisture. S-band (12 cm) gives finer detail for agriculture + surface change. Together: complementary, world-first capability.