On July 30, the Indian Space Research Organisation (ISRO), in partnership with NASA, will launch the highly anticipated NISAR satellite from Sriharikota using a GSLV Mk-II rocket. Officially named the NASA-ISRO Synthetic Aperture Radar (NISAR), this Earth observation satellite is set to monitor and map everything from earthquakes and landslides to crop patterns and urban subsidence.

The anticipated Rs 12,500-crore mission is more than just another satellite, it’s a collaboration between the two leading space agencies and a technological leap in radar-based Earth imaging. But what makes NISAR so unique, and how will it help India and the world? Here’s a complete guide.

What is the NISAR satellite?

NISAR is the world’s first Earth observation satellite with dual-frequency radar — combining NASA’s L-band SAR (1.257 GHz) and ISRO’s S-band SAR (3.2 GHz) systems. That means it can penetrate clouds, vegetation, and even soil to detect changes on Earth’s surface—whether it’s an underground water shift, deforestation, crop growth, glacier movement, or tectonic shifts.

At nearly 3 tonnes and costing over $1.5 billion, NISAR is also one of the most expensive Earth-monitoring satellites ever built.

Why do we need NISAR?

The Earth is constantly changing due to climate change, natural disasters, and human activity. Satellites like NISAR provide real-time, detailed information to track these changes. But unlike optical satellites, which are limited by weather and lighting conditions, NISAR’s radar can scan the planet day and night, through clouds, smoke, and rain.

Its precise imaging will be crucial for:

• Disaster management (earthquakes, floods, landslides)

• Crop monitoring and food security

• Infrastructure health (bridges, roads, dams)

• Ice sheet tracking and ecosystem studies

• Groundwater and soil health mapping

For India, it’s especially valuable for monitoring farmland, forests, and high-risk seismic zones.

How will NISAR work?

After launch, NISAR will orbit the Earth at an altitude of 747 km in a sun-synchronous polar orbit, covering the entire planet every 12 days. But it’s not your average camera-in-space—NISAR uses Synthetic Aperture Radar (SAR), a technique that simulates a massive radar antenna by combining radar pulses captured over time.

Key technical specs:

• Swath width: 240 km (wide enough to cover large land areas quickly)

• Spatial resolution: 3 to 10 meters (can detect centimetre-scale ground movement)

• Radar combo: L-band (deep penetration, used globally) + S-band (high detail, focused on India)

• Scan frequency: Each ground point revisited every 12 days

ISRO will use the S-band radar primarily over India to assess crop yields, forest biomass, and land deformation, while NASA’s L-band scans will offer global data.

What’s in it for India?

While it’s a joint mission, India has a big stake in the project. ISRO has developed the spacecraft bus, S-band radar, launch integration, and end-to-end mission operations for Indian users. Key benefits for India include:

• Dedicated data streams for agriculture, forestry, and disaster relief

• Faster response times: Damage proxy maps can be delivered within 5 hours during disasters

• Support for state-level water management, land subsidence, and flood preparedness

• Boost to India’s global satellite capability and research collaborations

NISAR will also generate high-resolution crop maps quarterly, and biomass estimates annually, key to India’s rural economy and food policy.

 How was NISAR built?

NISAR’s construction was an engineering feat spread across continents:

• NASA built the L-band radar system, 12-m mesh antenna, and radar structure via its Jet Propulsion Laboratory (JPL).

• ISRO contributed the I-3K satellite bus, S-band radar, power systems, and data handling subsystems, developed at the Space Applications Centre, Ahmedabad.

• The final radar assembly happened at JPL, but integration and testing were done in Bengaluru.

• ISRO will launch the satellite from Sriharikota and handle daily flight operations via its Telemetry and Tracking Centre.

This kind of co-development between ISRO and NASA is rare and underscores India’s growing capability in deep space collaboration.

Where will the data go?

Once in orbit, NISAR will generate up to 3 TB of data per day, beamed down to NASA ground stations in Alaska, Chile, and Norway, and to ISRO’s stations in Shadnagar and Antarctica.

In India, the National Remote Sensing Centre (NRSC) will process and distribute the data to government departments, scientists, and public platforms.

Also, NISAR’s data will be free and open, a major boost for universities, startups, and policy planners.

What’s next?

The launch window opens on July 30, with NISAR scheduled to lift off on a GSLV Mk-II rocket from ISRO’s Satish Dhawan Space Centre. The mission has a planned life of 3 years, extendable up to 5, and is already drawing global attention.

As the world’s eyes turn to India’s coastline for this historic liftoff, NISAR represents more than a science mission, it’s a statement of India’s rising space power and its commitment to climate and disaster resilience through science.