NISAR (NASA‑ISRO Synthetic Aperture Radar) Satellite| Mission NISAR

www.hinsoli.com August 05, 2025

Name & Partnership: NASA‑ISRO Synthetic Aperture Radar (NISAR) — a landmark joint Earth‑observation satellite mission by the Indian Space Research Organisation (ISRO) and NASA / JPL (Wikipedia, ISRO).
Launch: Successfully launched on July 30, 2025, at 17:40 IST aboard ISRO’s GSLV‑F16 rocket from Satish Dhawan Space Centre, Sriharikota (ISRO).
Orbit & Lifespan: Placed into a 743–747 km sun‑synchronous dawn–dusk polar orbit, inclined at 98.4°, revisiting all land and ice surfaces globally every 12 days, with expected mission life of 3 years (NASA); 5 years for ISRO’s S‑band operations (ISRO).

Technical Specifications

Satellite mass: ~2,392 kg (≈2.4 tonnes) (India Today).
Bus & Platform: ISRO’s modified I3K satellite bus, 3‑axis stabilized (ISRO).
Radar instruments:
- L‑band SAR (1.257 GHz / ≈24 cm wavelength) by NASA/JPL with 12 m deployable mesh reflector and 9 m boom (Wikipedia).
- S‑band SAR (3.2 GHz / ≈9–12 cm) by ISRO for higher sensitivity to surface features (Wikipedia).
Imaging mode: SweepSAR—scan‑on‑receive wide‑swath mapping enabling ~240–242 km swath coverage, with spatial resolution ~5–10 m (some modes down to 3 m), and millimetre to centimetre‑scale vertical displacement sensitivity (India Today).
Data generation: Produces 80+ TB/day, downlinks via NASA’s Near Earth Network and ISRO’s ground stations; data access free and open – within 1–2 days, hours in emergencies (ISRO, Vajiram & Ravi).
Cost & Workshare:
- Cost ~US $1.5 billion total: NASA ≈$1.2 billion, India ≈₹91 crore (~US $0.09 billion) (AP News).
- NASA supplies L‑band radar, deployable antenna, data handling, GPS, telecom.
- ISRO provides bus, S‑band radar, launch services, ground infrastructure (NASA Science, Vajiram & Ravi).

Pre‑launch timeline:
- Originally scheduled for early 2024, delayed for reflector hardware upgrades; antenna sent back to NASA/JPL in October 2024 for reflective coating modifications (Wikipedia).
- Arrived in India June 2025, launch finalized for late July (Wikipedia).
Commissioning:
- ~90‑day In‑Orbit Checkout period: deployment of boom & reflector, calibration of radar sensors and spacecraft subsystems (ISRO).
Science Operations:
- Begins after commissioning; calibration & validation (CalVal) period ~5 months, then nominal operations.
- L‑band operations for 3 years; S‑band may continue up to 5 years if propellant lasts (NASA Jet Propulsion Laboratory).

NISAR is built to tackle six broad scientific themes, with particular utility for India and global needs:

Solid Earth Processes: Detect ground deformation related to earthquakes, volcanoes, landslides, subsidence—even at cm/mm scale (Vajiram & Ravi).
Cryosphere & Ice Dynamics: Monitor polar ice sheets, glaciers in Himalayas, ice shelf collapse and melting trends critical for sea-level forecasts (India Today).
Ecosystems & Biomass: Track forest cover, woody biomass, wetlands, biodiversity and deforestation/forest degradation (Vajiram & Ravi).
Hydrology & Agriculture: Observe soil moisture, surface water, wetlands; support irrigation planning, groundwater monitoring, crop health analysis (The Hindu, India Today).
Coastal & Ocean Monitoring: Shoreline erosion, storm surges, coastal subsidence, ship detection, oil spills and sea ice classification (Vajiram & Ravi).
Disaster Response: Provide rapid damage proxy maps within ~5 hours of events like floods, storms, fires, earthquakes to aid relief planning (Vajiram & Ravi).

All‑weather, day‑night imagery: Radar penetrates clouds, darkness, vegetation—ensures consistent data during monsoons, polar nights, smoke, storms (India Today).
India’s benefits: Supports Himalayan glacier tracking, monsoon‑agriculture planning, soil‑moisture mapping, subsidence monitoring of infrastructure, disaster preparedness and ecological management (India Today, Vajiram & Ravi, ISRO).
Open‑data ethos: All users—global researchers, governments, NGOs—can access data freely: within ~1–2 days or hours in emergencies (Vajiram & Ravi).
Diplomatic & scientific value: A milestone in India‒U.S. space cooperation; demonstrates India’s growing space capability and peaceful application of science for humanity’s benefit (India Today).
Local contributors: Indian scientists like Prof. Manikandan Mathur (IIT-Madras) optimized algorithms for coastal monitoring, and ISRO engineers such as Subhradip Ghosh played key roles in propulsion and system readiness (The Economic Times).

Feature	Details
Launch Date & Time	July 30, 2025 at 17:40 IST
Launch Vehicle	GSLV‑F16 (Mk‑II)
Orbit Altitude & Inclination	~747 km, 98.4° sun‑synchronous polar
Mass	~2,392 kg
Radars	L‑band (NASA), S‑band (ISRO), dual‑frequency
Swath Width	~240–242 km
Resolution	~5–10 m (spatial); mm–cm (vertical/deformation)
Repeat Cycle	Every 12 days
Mission Duration	3 years (NASA L‑band), up to 5 (ISRO S‑band)
Data Volume	~80+ TB/day
Data Policy	Open access within hours/days

NISAR is the first radar satellite to combine dual‑frequency SAR on a single platform, enabling high‑resolution, wide‑swath Earth imaging regardless of weather or light (India Today, ISRO).
Scientific impact spans climate monitoring, geology, agriculture, ecosystem management, urban subsidence, glaciers, and rapid disaster response.
Strategic collaboration: A decade in planning, with complementary engineering from NASA and ISRO, it sets a precedent for future global Earth‑science missions (AP News).