THE CONTEXT: India’s 2012‑13 Himalayan floods revealed critical gaps in centimetre‑level land‑motion data. Parallelly, NASA’s “DESDynI” radar mission was shelved for budget reasons. Converging interests birthed the NASA‑ISRO Synthetic Aperture Radar (NISAR) pact in 2014, formalised by an MoU in 2016 and an inter‑governmental agreement in 2019. The mission now readies for a 30 July 2025 launch on GSLV‑F16 from Sriharikota, carrying the costliest earth‑observation payload ever: US $1.5 billion.
MISSION OBJECTIVES:
NISAR will revisit every land pixel in 12 days, capturing millimetric deformations. Its open‑data policy (delivery within hours) directly advances Sustainable Development Goals 2, 11, 13 & 15 by:
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- measuring crop biomass for precision agriculture,
- mapping groundwater‑induced subsidence in megacities,
- providing five‑hour “damage proxy maps” after disasters.
TECHNICAL ARCHITECTURE & SPECIFICATIONS:
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- Orbit: Sun‑synchronous, 747 km, 98.4°.
- Radars: Co‑located L‑band (24 cm, NASA) and S‑band (9.4 cm, ISRO) SweepSARs with 240 km swath and 3‑10 m ground resolution.
- Antenna: 12 m deployable AstroMesh on a 9‑m carbon‑composite boom.
- Throughput: 3 TB/day down‑linked via NASA Near‑Earth Network; mirrored by ISRO’s NRSC at Shadnagar.
GEOSPATIAL GOVERNANCE & SPACE DIPLOMACY:
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- India gains assured radar data while the U.S. shares costs and orbits otherwise inaccessible due to ITAR regimes. Such “co‑development satellites” are labelled functional spill‑overs that deepen strategic trust.
STRATEGIC SIGNIFICANCE FOR INDIA:
| DOMAIN | ILLUSTRATIVE NISAR PAY OFFS |
|---|---|
| Solid Earth | Continuous slip rate mapping of the Main Himalayan Thrust; input for National Seismic Risk Index. |
| Ecosystems & Agriculture | 1 ha woody biomass maps aid Green Credit Scheme; S band moisture retrieval refines Pradhan Mantri Fasal Bima Yojana premiums. |
| Cryosphere | Weekly mass balance of Hindu Kush glaciers; calibrates National Mission on Sustaining Himalayan Ecosystem. |
| Coastal & Ocean | Detects mangrove loss and shoreline erosion feeding Sagarmala port planning. |
| Disaster Response | 5 hour damage proxies integrate with C DSS (Common Alerting Protocol) under NDMA. |
| ‘Plus’ Uses | Monitoring tilt in dams, metro tunnels; methane leak detection to meet Panchamrit targets. |
INDIAN POLICY ECOSYSTEM:
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- National Geospatial Policy 2022 mandates open public‑funded geodata, easing downstream start‑ups.
- PM Gati‑Shakti 240 km swath provides uniform base layers for the NMP portal.
- Indian Space Policy 2023 & IN‑SPACe rules enable non‑government entities to commercialise value‑added SAR analytics.
GLOBAL PERSPECTIVE:
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- EU Sentinel‑1 (C‑band) offers 20 × 250 km coverage but lower biomass sensitivity.
- NASA‑CNES SWOT maps surface water height yet lacks solid‑earth focus.
- Japan’s ALOS‑4 provides 1 m L‑band imagery but with 14‑day revisit.
- NISAR’s dual‑band SweepSAR is a first‑mover, positioning India in the high‑end SAR value chain.
THE ISSUES:
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- Calibration complexity: Dual‑band cross‑talk demands dense global corner‑reflector networks; India currently has only 18.
- Petabyte‑scale data deluge: NRSC’s present 1 Pb annually must triple; cloud‑agnostic pipeline still under procurement.
- SAR literacy gap: Only five Indian universities run advanced InSAR courses, limiting skilled analysts.
- Data sovereignty & dual‑use: High‑resolution deformation maps could aid hostile intelligence; policy needs tiered latency for sensitive zones.
- Launch risk: GSLV‑Mk‑II has 86 % success; any anomaly jeopardises Indo‑US goodwill.
- S‑band rain attenuation: Monsoon downpours can degrade S‑band returns, complicating agricultural time‑series.
- Inter‑agency coordination: Ministries still operate siloed GIS stacks; lack of a unified SAR tasking dashboard delays response.
- Financing downstream apps: Venture capital wary of long RoI; Digital Public Goods funding model yet to evolve.
The Way Forward:
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- Nation‑wide Corner Reflector Grid: Deploy 200 low‑cost trihedral reflectors via IIT‑ISRO MoUs to auto‑calibrate phase data within six months.
- Cloud‑native Data Lake: Fast‑track NRSC‑AWS hybrid under Digital India e‑Governance to permit Jupyter‑based analytics pipelines for start‑ups.
- SAR Skilling Mission: Introduce a two‑semester “Applied InSAR” elective in AICTE curricula; leverage SWAYAM for remote learners.
- Tiered‑Latency Policy: Release civilian tiles in near‑real‑time while delaying sensitive border strips by 72 hours, balancing openness with security.
- GSLV Reliability Upgrade: Adopt FMECA‑led redesign of cryogenic stage valves; simulate 1,000 duty cycles before the next Mk‑II flight.
- Monsoon Noise Modelling: Co‑fund IISc to build AI filters using co‑located disdrometers, enhancing S‑band crop retrieval accuracy by 30 %.
- Unified SAR Tasking Cell: Integrate NISAR queue into NDMA’s Decision Support System; pre‑define “hurricane macros” for auto‑imaging.
THE CONCLUSION:
NISAR is more than a satellite; it is India’s leap from cartographic dependence to geospatial leadership, aligning “Viksit Bharat 2047” with global climate stewardship. If governance converts petabytes into policy insights, NISAR could become the Aadhaar of Earth‑system data.
UPSC PAST YEAR QUESTION:
Q. Discuss India’s achievements in the field of Space Science and Technology. How the application of this technology has helped India in its socio-economic development? 2016
MAINS PRACTICE QUESTION:
Q. NISAR exemplifies the transition from data scarcity to data deluge in India’s geospatial regime. Analyse the technological novelties of NISAR.
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