Explainer: Can NISAR satellite aid India's military intelligence, besides serving civilian goals?

The Indian Space Research Organisation and the United States’ National Aeronautics and Space Administration have fixed July 30 for the launch of the NASA-ISRO Synthetic Aperture Radar (NISAR), a joint project to develop and launch a high-resolution Earth imaging satellite.

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ISRO’s Geo-Synchronous Launch Vehicle F16 will lift off with the satellite from the Satish Dhawan Space Centre in Sriharikota and inject it into a polar sun-synchronous orbit 743 km above the Earth. This type of orbit, in which satellites pass over any given point on Earth at the same local mean solar time, is useful for imaging, reconnaissance and weather satellites because of the illumination of the surface by the sunlight.

What makes the technology unique

NISAR will scan the entire globe twice every 12 days, providing high-resolution, all-weather, day-and-night data. It can detect even subtle changes in Earth’s surface — like ground deformation, ice sheet shifts and vegetation dynamics.

According to ISRO, the mission would support many critical applications, including sea ice monitoring, ship detection, storm tracking, soil moisture changes, surface water mapping and disaster response.

The 2,392-kg satellite will be the first space platform to observe the earth with a dual frequency Synthetic Aperture Radar (SAR) – NASA’s  L-band and ISRO’s S-band. These will detect changes in the planet’s surface down to “fractions of an inch”.

SAR was originally developed to meet military requirements, and in the words of a senior NASA scientist, “allows us to refine things very accurately”. To have the same imaging capability as SAR, the antenna of a traditional radar would have to be about 1,580 times bigger. The satellite will generate about 80 terabytes of data per day.

A civilian project, officially

“The data will be accessible to all users across a range of disciplines, with potential applicability in disaster response, infrastructure monitoring and agricultural decision support,” NASA said. All data from NISAR will be available 1-2 days after observation and within hours in case of emergencies like natural disasters.

NISAR is projected as a civilian project focused on Earth observation for scientific purposes, particularly for understanding changes in ecosystems, ice mass, vegetation and natural hazards. Official statements have denied the satellite having any military applications and have hailed it as a milestone in India-US civil space cooperation.

Suitable of monitoring border zones too

Theoretically, and speculatively, the data derived from NISAR could be used for defence purposes, even though it may not always generate real-time intelligence. NISAR’s ability to penetrate into clouds, smoke, fog and dense vegetation makes it suitable for monitoring strategic areas like borders or conflict zones and detect surface changes and infrastructure development that have cropped up within a period of a few days. This makes it useful for strategically mapping military installations, construction of fortifications or border posts, building roads and bridges or tracking large scale troop and vehicle movements.

Since terrain analysis is a vital element in planning military deployment and conducting operations, data from the satellite could potentially be used in this arena. The Defence Research and Development Organisation has a dedicated laboratory, the Defence Geoinformatics Research Establishment (DGRE) based at Chandigarh that develops geospatial information for operational planning and military intelligence.

Satellites have become critical for generating strategic as well as tactical intelligence, besides enabling network-centric operations for real time flow of information to commanders and operators across the hierarchy.

India's satellite capabilities vs China's

India, at present does not have strategic reconnaissance aircraft like the trisonic, ultra-high altitude MiG-25R that the IAF operated from 1981 to 2006. It relies on fighter aircraft equipped with externally mounted recce pods and drones for tactical recce and satellites for imagery. India has several earth observation and communication satellites, but their capabilities are limited.

Some limitations came to the fore during Operation Sindoor in May this year when India and Pakistan engaged in a brief but intense four-day military confrontation. China is said to have provided real-time intelligence on Indian military assets to Pakistan based on satellite imagery.

According to Defence sources, Chinese satellites have the capability to generate updated data at six-hour intervals, while Indian satellites take much longer. For many years, India has also been procuring high-resolution satellite images for military applications from foreign commercial vendors, but these are expensive.

Though Indian satellites have been playing a significant role in information gathering and operational planning, the armed forces are believed to have stepped up efforts to procure foreign satellite images in the aftermath of Operation Sindoor to plug existing gaps and enhance surveillance.

As of 2024, India operates nine satellites for defence purposes. Among them, two GSAT-7 and GSAT-7A are dedicated military satellites, while the rest like HySIS, CartoSat, EMISAT, RISAT and EOS are dual purpose satellites. Six more satellites have military applications planned for launch in the near future.

In India, the Defence Space Agency (DSA) — a tri-services agency under the Integrated Defence Staff headquartered at Bengaluru — is responsible for operating satellites and conducting space-warfare, including research, threat assessment, anti-satellite programmes and doctrinal aspects.

India's space surveillance journey for military intelligence

India’s foray into using space for military purposes began with the ‘Space Based Surveillance Phase-I’ project, which was approved by the Vajpeyee government in 2001. As a part of this, four satellites — Cartosat-2A, Cartosat-2B, EROS-B and RISAT-2 — were launched. Space Based Surveillance Phase – II was approved in 2013, which saw six satellites — Cartosat-2C, Cartosat-2D, Cartosat-3A, Cartosat-3B, Microsat-TD, RISAT-2A — being put in space, according to reports.

In October 2024, the Cabinet Committee on Security approved a proposal for the development, construction and launch of at least 52 satellites as a part of Space Based Surveillance Phase-III for round the clock, all weather reconnaissance and surveillance from space across land and sea domains, as well as enhancing secure communications capability.

The project, estimated to be worth Rs 26,968 crore, will be supervised by the National Security Council Secretariat along with the DSA. ISRO will construct 21 satellites while the remaining 31 will be built by the private sector.