Eyes In the Sky: How India's Satellite Fleet Is Leading The Charge In National Defence

News18

20-05-2025

Last Updated:
India has built one of the largest remote-sensing satellite networks ramping up with the launch of its first radar imaging satellite RISAT-1 in 2009 post the 2008 Mumbai attacks.
With the Army on the ground, the Navy at sea, and pilots in the air, India boasts of one of the largest and formidable defence forces in the world. Now it's the country's rapidly-advancing satellite coverage that bolsters its border surveillance, day and night, under all weather conditions, becoming a backbone for strategic defence.
'At least 10 satellites are continuously working round-the-clock for the strategic purpose to ensure the safety and security of the citizens of the country. We have to monitor our 7,000 km seashore areas and the entire Northern part continuously. Without satellite and drone technology, we can't achieve that," said Dr V Narayanan, ISRO chairman last week in Imphal.
With the IRS series, Cartosat, Oceansat, Resourcesat, and RISAT (Radar Imaging Satellites), India has built one of the largest constellations of remote sensing satellites in operation providing images with different spatial, spectral, and temporal resolutions to meet different users. The recent tensions with neighbouring Pakistan highlighted significant capabilities of this network.
'Our existing capabilities are very good, and have become more robust with the launch of radar imaging satellites (RISAT series). If we look at the pictures from Operation Sindoor, the pictures showing clear damage to air fields – whether taken by satellites or UAVs – were very clear. We need to keep strengthening our constellation further to ensure continuous, 24X7 surveillance round the clock," said Ajay Lele, Deputy Director General, MP-IDSA, New Delhi.
ADVANCED RADAR IMAGING SATELLITES
ISRO's launch of the first radar imaging satellite in 2009 post the 2008 Mumbai attacks provided a shot in the arm, delivering 24-hour imagery under all-weather data, day and night enhancing border surveillance for 13 years, until its re-entry in 2022. Since then, it has launched RISAT-1A in 2012, and RISAT-2BR1 in 2019 each carrying a mission life of five years.
The latest launch of EOS-09, which could not be accomplished, would have further strengthened these capabilities, injecting one more Radar Imaging Satellite (RISAT-1B) into space. Since most of these satellites are in polar, sun-synchronous orbits, they provide consistent coverage by revisiting the same location, at the same local time each day.
EYE ON THE BORDERS, DAY AND NIGHT SURVEILLANCE
The Synthetic Aperture Radar on these satellites plays a crucial role in strategic defence as it provides high-resolution data, day and night under all-weather conditions. In spotlight mode, the radar signal can be focussed on a specific area to capture high-resolution images especially critical for military installations and infrastructure. The longer the time that radar spends over a target, the better the resolution. Multiple radar pulses create a more detailed image.
Since most of these satellites have dual purpose, they serve critical strategic needs, and at the same time, provide useful data for various other sectors. While the high-resolution imagery is only shared with government and military users, the images for mapping agriculture, urban planning, water resources, landslides, glaciers, ground water potential, disaster management, forest biomass estimation continue to be used for multiple other applications.
India's capabilities will get a major boost with the much-anticipated launch of NISAR-NASA-ISRO Synthetic Aperture Radar in June-July this year – which will offer unprecedented view of the Earth, mapping the entire globe with precision every 12 days, and capture places that have otherwise been obscured. The satellite will be able to detect changes as small as 10 m, piercing through dense cloud dover, day and night.
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