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In an era where climate change, natural disasters, and ecological degradation are becoming more pressing global concerns, advanced space-based Earth observation has emerged as a vital tool. The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a landmark collaboration between the National Aeronautics and Space Administration (NASA) and the Indian Space Research Organisation (ISRO).
NISAR represents the most advanced dual-frequency radar satellite ever developed for civilian use. Once operational, NISAR will monitor Earth’s land and ice surfaces with high precision. It will capture surface movements down to fractions of an inch, aiding in studying tectonic shifts, glacier dynamics, forest health, and infrastructure stability. It can transform how we understand and respond to changes on Earth’s surface, ranging from glacial movements to forest biomass, from seismic activity to urban land subsidence.
The latest update on the NASA-ISRO Synthetic Aperture Radar (NISAR) mission indicates that the launch is scheduled for late May to June 2025, a shift from the anticipated March 2025 timeline. This delay, caused by thermal coating issues with the 12-meter radar antenna reflector, was resolved by October 2024. Despite the delay, the mission’s objectives and timeline remain intact. Final integration and testing are underway at ISRO’s facilities in Bengaluru. The satellite is expected to be transported to the Satish Dhawan Space Centre in the coming weeks to prepare for its launch aboard a GSLV Mark II rocket.
NISAR Project: Collaborative Effort
Genesis. The NISAR mission concept emerged from NASA’s 2007 Decadal Survey, which called for advanced SAR data to address gaps in Earth science. Formalised in 2014 with a partnership agreement, the project has progressed through rigorous design, testing, and integration phases. NASA’s Jet Propulsion Laboratory (JPL) and ISRO’s Space Applications Centre have worked closely to refine the mission’s science plan and hardware.
Project Details. The NISAR mission is designed to provide unprecedented global radar imagery using L-band and S-band synthetic aperture radars. NASA has provided the L-band radar system, high-rate communication subsystem, GPS receivers, and payload data systems. ISRO is contributing the S-band radar, satellite bus, and launch services via the GSLV Mk II from the Satish Dhawan Space Centre. The satellite will be placed in a sun-synchronous polar orbit at about 747 kilometres and revisit the exact location on Earth every 12 days. The SAR payload will produce radar images with a resolution of 5–10 meters and a swath of 240 kilometres, enabling wide-area monitoring of Earth’s surface with high precision. The unique dual-band system of NISAR allows it to penetrate vegetation, ice, and soil more accurately than single-frequency satellites, making it a game-changer in Earth observation. The L-band is particularly effective for tracking subsurface movement and biomass, while the S-band is more sensitive to finer surface features.
Collaboration. The NISAR partnership exemplifies international cooperation in space exploration. NASA’s investment, estimated at $1.118 billion, covers the L-band radar and critical subsystems, while ISRO’s contribution, approximately ₹788 crore ($92 million), includes the S-band radar, spacecraft bus, and launch services. This division of responsibilities optimises costs and expertise, building on NASA’s legacy of SAR missions (e.g., SEASAT in 1978) and ISRO’s advancements in satellite technology (e.g., the Chandrayaan missions). The collaboration extends beyond hardware. Joint workshops, working groups, and the NISAR Utilisation Programme announced by ISRO in July 2023 engage the global scientific community, fostering data analysis and application development. The mission’s open data policy aligns with the principles of transparency and collaboration, setting a precedent for future NASA-ISRO endeavours, including potential Mars exploration missions.
Mission Objectives and Scientific Impact
NISAR’s primary goal is to make global measurements of land surface changes, detecting movements as small as a centimeter. By mapping the globe every 12 days, the satellite will generate spatially and temporally consistent data, offering insights into complex Earth processes. Its objectives span three key domains: deformation, ecosystem structure, and ice dynamics. NISAR will monitor seismic zones, volcanic activity, and landslide-prone areas for deformation, providing early warning signs for natural disasters. In ecosystem studies, it will track forest extent, vegetation biomass, and agricultural patterns, aiding sustainable resource management. NISAR will measure glacier flow rates and ice-sheet stability for ice dynamics, contributing to our understanding of climate change and sea level rise.
All NISAR data will be freely available within one to two days of observation or hours for emergencies like natural disasters. This accessibility and NISAR’s high-resolution imagery (5-10 meters) will empower scientists, policymakers, and disaster response teams worldwide. The data can enhance infrastructure monitoring, improve agricultural management, and inform rapid disaster response, potentially saving lives and property. The open data policy also encourages collaboration and innovation, allowing for the development of new applications and tools to further leverage NISAR’s capabilities.
Applications
Natural Disaster Monitoring and Response. NISAR will be critical in mapping the aftermath and precursors of earthquakes, floods, volcanic eruptions, and landslides. The radar’s ability to detect minute ground deformations will help forecast and emergency response, reducing the human and economic cost of such events.
Climate Change Observation. The satellite will track ice sheet movement in Antarctica and Greenland, glacial retreat in the Himalayas, and coastal subsidence, all critical indicators of global climate change. NISAR data will also assist in modelling sea level rise and understanding the behaviour of the permafrost regions, which store vast amounts of greenhouse gases.
Agriculture and Forestry. NISAR’s radar can estimate biomass and crop yield, making it invaluable for food security planning and carbon stock assessment. It will monitor deforestation, forest degradation, and land-use changes, helping countries meet international commitments such as those under the Paris Agreement and REDD+ initiatives.
Urban Infrastructure Monitoring. Urban planners and disaster mitigation agencies can use NISAR to monitor growing cities’ subsidence, groundwater depletion, and infrastructure stress. Its precise deformation measurements can help predict building collapses, dam failures, and roadbed weaknesses.
Scientific and Tectonic Research. Scientists will use NISAR to understand better plate tectonics, fault line dynamics, and volcano formation. The L-band radar, in particular, is ideal for detecting ground movements as small as a few millimetres, critical for early warnings in earthquake-prone regions.
Strategic Significance
The NISAR mission is a scientific milestone and a strategic symbol of the growing India-US partnership in space technology. It reflects significant technological trust and collaborative capacity-building, especially as China expands its space and Earth observation programs.
For India, the mission provides access to advanced radar imaging technology, enhances its global space diplomacy profile, and contributes to developing disaster management and environmental monitoring capacity. For the U.S., NISAR extends Earth observation to low-latitude and tropical regions, which are difficult to monitor from NASA’s polar-focused satellites.
Conclusion
NISAR stands at the intersection of science, diplomacy, and strategic policy. As the world’s most advanced Earth-observing radar satellite, it will provide a detailed, dynamic picture of the planet’s changing surface. Whether helping farmers optimise irrigation, supporting relief efforts after natural disasters, or aiding climate scientists in tracking global warming, NISAR will become an indispensable part of humanity’s Earth-monitoring infrastructure.
By combining ISRO’s cost-effective engineering and operational expertise with NASA’s deep technological experience, NISAR heralds a new era in Earth observation and exemplifies the international collaboration required to tackle global challenges.
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References: –
- Indian Space Research Organisation. (2024). NASA-ISRO SAR (NISAR) Mission Overview. Retrieved from https://www.isro.gov.in
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