Jul 24, 2025
15
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The launch of NISAR has been formally scheduled for July 30, 2025 at 17:40 IST from India’s Satish Dhawan Space Centre aboard the GSLV‑F16 rocket. NISAR is $1.5 billion joint Earth-observation satellite mission equips both L‑band and S‑band radar systems to scan nearly all of Earth’s land and ice surfaces every 12 days. NISAR will provide crucial data on natural hazards, ecosystem changes, ice-mass dynamics, and land deformation-strengthening Indo-US cooperation in space-based climate and disaster monitoring.
The NISAR satellite represents a groundbreaking collaboration between NASA and the Indian Space Research Organisation (ISRO) aimed at enhancing our understanding of Earth's surface changes. Utilizing cutting-edge synthetic aperture radar (SAR) technology, this radar imaging satellite is designed to monitor the planet's surface with unprecedented detail. Equipped with a sophisticated radar antenna and advanced radar imaging capabilities, NISAR can create high-resolution images that reveal subtle changes across the globe. What sets NISAR apart as the first satellite mission of its kind is its ability to operate using two different radar frequencies-L-band and S-band-allowing for comprehensive radar data collection of the Earth's surface. The mission's primary goal is to deliver critical scientific data on natural hazards, sea level rise, ice masses, and land surface changes, which are vital for climate and environmental research worldwide.
What is NISAR’s full form and What is the NISAR Mission?
NISAR Full form: NASA-ISRO Synthetic Aperture Radar.
NISAR Mission: It’s an Earth‑observation satellite jointly developed by NASA and ISRO, equipped with dual‑frequency (L‑band and S‑band) radar to monitor surface and ice changes with centimeter‑level precision, regardless of weather or daylight.
Table of content
Parameter | Details |
NISAR Mission Category | Earth‑observation satellites(Radar Imaging) |
NISAR Launch Date | July 30, 2025 at 17:40 IST |
NISAR Launch Vehicle | GSLV Mk II |
NISAR Launch Site | Satish Dhawan Space Centre |
NISAR Mission Life | 3 years (nominal) |
Repeat Cycle | 12 days (global coverage) |
NISAR Satellite Orbit | Sun‑synchronous LEO at ~734 km altitude |
L‑band Wavelength | ~25 cm |
S‑band Wavelength | ~10 cm |
NISAR Satellite Radar Instruments | L-band Synthetic Aperture Radar (L-SAR) (by NASA) & S-band Synthetic Aperture Radar (S-SAR) (by ISRO) |
This technologically advanced payload structure underpins NISAR’s ability to produce reliable, all-weather, day/night radar data-key for understanding and responding to environmental challenges. It also illustrates the fusion of synthetic aperture radar, dual-frequency radar systems, and innovative satellite design in Earth Observation missions.The NISAR satellite carries two synergistic radar instruments and a deployable antenna system, making it the world’s first dual-frequency radar imaging satellite:
Dual-Frequency Radars
L‑band Synthetic Aperture Radar(SAR) (~24–25 cm wavelength)
Developed by NASA’s Jet Propulsion Laboratory (JPL)
Long wavelength penetrates dense vegetation, surface soil, and canopy—revealing subsurface structures and enabling study of solid Earth processes and ice mass dynamics.
S‑band Synthetic Aperture Radar(SAR) (~9–10 cm wavelength)
Developed by Indian Space Research Organisation (ISRO)
Shorter wavelength excels at detecting surface changes like crop moisture, soil moisture, and fine land deformation—complementing L‑band data with higher-resolution surface detail.
This combination enables the NISAR satellite to capture both deep and surface-level phenomena, essential for monitoring ice masses, ecosystems, agriculture, sea level rise, and natural hazards.
What is Synthetic Aperture Radar(SAR)?
Synthetic Aperture Radar (SAR) is an active remote sensing technology that transmits microwave pulses from a moving satellite or aircraft, then records their echoes to create high‑resolution images. Using signal processing to combine data from multiple positions, SAR produces detailed imagery day or night, in any weather
Key advantages of Synthetic Aperture Radar(SAR):
Operates in all weather conditions.
Works day and night, regardless of sunlight.
Provides fine spatial resolution via synthetic aperture processing
NISAR Mission: Deployable Antenna Reflector
The NISAR satellite features a massive 12‑meter deployable mesh antenna, mounted on a 9-meter boom—the largest ever launched by NASA.
This large reflector delivers exceptional high resolution (~1 cm sensitivity) over wide swaths (~240 km), enabling detection of subtle ground movements like subsidence or shifting glaciers.
Continuous Coverage via SweepSAR Technique
By moving in sun-synchronous orbit (~734 km altitude, 12-day repeat cycle), NISAR’s Synthetic Aperture Radar(SAR) uses SweepSAR:
Transmits a focused beam across a wide swath (~242 km)
Sweep-enabled phased-array feed dynamically receives signals across the reflector, combining wide-area coverage with fine spatial resolution.
Capable of mapping any land surface twice in each 12-day cycle (ascending + descending), regardless of weather or lighting—ensuring consistent detection of changes.
NISAR’s mission is to measure dynamic changes on Earth’s surface with unprecedented detail. Its science goals include:
Monitoring Land Deformation:
Mapping horizontal and vertical ground movements (e.g. tectonic shifts, subsidence, volcanic uplift) to improve hazard models.
By comparing repeated radar images, NISAR satellite can reveal creep on faults or subtle ground shifts (millimeter-to-centimeter scale) over time..
Cryosphere and Sea-Level:
Tracking ice sheets, glaciers, permafrost, and polar sea ice.
NISAR will quantify ice mass changes and sea-level rise by observing ice-covered regions globally.
This will enhance understanding of climate-driven ice melt and its impact on coastal regions.
Natural Hazard Surveillance:
Providing data for disaster management. NISAR satellites imagery will help detect and monitor earthquakes, volcanic unrest, landslides, flood inundation and tsunamis.
Frequent radar maps allow for near-real-time updates on crisis zones, aiding early warning and response.
Environmental Change and Land Use:
Assessing vegetation, forests, agriculture, and water resources. By measuring changes in biomass, soil moisture, and land cover, NISAR supports ecosystem and agricultural management.
For example, it can map deforestation, monitor crop health, and track the extent of wetlands.
Global Climate Studies:
Supplying precise data on climate processes.
Continuous NISAR measurements will improve models of how climate change is reshaping Earth’s surface.
e.g. glacial retreat, shifting ecosystems
Scientists will use NISAR datasets to advance understanding of carbon and water cycles, weather patterns, and land-atmosphere interactions.
First Dual‑Frequency Radar Imaging Satellite: NISAR is the first to combine L‑band and S‑band SAR, enabling all‑weather and day‑night mapping of land surface and ice masses with ~1 cm accuracy.
Revolutionises Disaster Preparedness: NISAR’s 12‑day revisit cycles provide timely updates for natural hazards—earthquakes, landslides, floods—boosting early warning systems.
Climate and Environmental Impact: High-resolution monitoring of sea level rise, glacier melt, permafrost, and biomass supports climate models and India’s climate policies.
Strengthens India’s Global Standing: NASA-ISRO collaboration underscores India’s growing leadership in space diplomacy and data-sharing for scientific data initiatives.
As NISAR enters its science operations phase, its continuous, high‑resolution SAR datasets will underpin a wide array of applications:
Disaster Management & Resilience: Enhanced surface‑deformation maps will feed into predictive models, enabling authorities to prepare for earthquakes, landslides, and floods with greater precision.
Agricultural & Water Resource Planning: Soil‑moisture estimates and land‑use change detection will guide crop management, irrigation scheduling, and drought mitigation.
Infrastructure Monitoring: Precise ground‑movement tracking supports stability assessments of dams, bridges, and urban developments, reducing maintenance costs and failure risks.
Climate Research & Policy: Long‑term observations of ice‑mass balance and sea level rise will refine global climate models, informing international environmental agreements.
Ecosystem & Forestry Management: Biomass change detection aids in monitoring deforestation, habitat loss, and carbon‑stock assessments for conservation planning.
Technological Innovation: Open-access scientific data from NISAR will spur new algorithms in synthetic aperture radar SAR processing, machine learning applications, and digital infrastructure enhancements across Earth sciences.
Enhanced Disaster Management
Real‑time mapping of land surface changes, flood extents, and subsidence
Improved early‑warning systems for earthquakes, landslides, cyclones, and tsunamis
Data‑driven response planning to minimise loss of life and property
Agriculture & Water Security
Soil‑moisture and crop‑health monitoring for precision farming
Drought and irrigation scheduling support via regular vegetation and moisture indices
Groundwater recharge assessment in drought‑prone regions
Climate Change Research
Quantification of ice masses loss and glacier retreat in the Himalayas
Measurement of sea level rise impacts on India’s coasts
Contributions to national climate models and India’s NDC targets under the Paris Agreement
Strengthening India’s Space Capabilities
Showcases ISRO’s expertise in deploying S‑band SAR and GSLV launch vehicles
Fosters technology transfer and joint science operations with NASA
Elevates India’s profile in international space diplomacy and open‑data initiatives
Q. When is the launch date of the NISAR Mission?
A. The launch date of NISAR has been formally scheduled for July 30, 2025 at 17:40 IST from India’s Satish Dhawan Space Centre aboard the GSLV‑F16 rocket
Q.What does NISAR stand for, and what is its mission?
A.NISAR stands for NASA-ISRO Synthetic Aperture Radar. It is a joint Earth-observation satellite mission by NASA and ISRO using advanced radar instruments (L-band and S-band) to monitor the land surface for environmental changes.
Q.Why does the NISAR satellite use both L-band and S-band radars?
A.Having two radar frequencies allows complementary data. The longer L-band penetrates vegetation, soil and ice to reveal deeper structures, while the shorter S-band provides higher-resolution detail of the land surface. Together, they improve overall change detection.
Q. How often will NISAR map the globe?
A.NISAR will scan nearly all of Earth’s land and ice every 12 days]. Its polar sun-synchronous orbit and dual-SAR design enable it to cover the planet twice in each 12-day cycle, providing frequent updates on environmental conditions.
Q.What makes NISAR different from previous satellites?
A.NISAR is the first satellite to carry two different SARs on one platform. With its 12-metre antenna and dual-frequency design, it offers unprecedented all-weather, day-and-night radar imaging of Earth’s surface. Its data rate (~80 TB/day) and resolution (~1 cm) are far higher than earlier missions.
The NISAR mission represents a major advancement in Earth observation, utilizing dual-frequency synthetic aperture radar (SAR) to deliver high-resolution data on the planet’s surface. This joint effort by NASA and Indian Space Research Organisation(ISRO) enables continuous monitoring of natural disasters, climate change, and land surface changes. By combining NASA’s radar expertise with ISRO’s satellite and launch capabilities, the mission strengthens international scientific collaboration. For India, NISAR enhances access to critical environmental data and deepens technological cooperation. As it enters the science operations phase, NISAR is set to provide valuable insights for researchers, policymakers, and disaster management agencies worldwide-contributing to a more informed and resilient planet.
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