Op Sindoor and ISRO’s proposed launch of radar imaging satellite RISAT-1B – Firstpost

The Indian Space Research Organisation (ISRO) is set to launch the radar imaging satellite RISAT-1B, equipped with advanced Earth observation capabilities, aboard the PSLV-C61 on May 18, 2025. This launch is particularly noteworthy in the context of Operation Sindoor. Such satellites are important towards strengthening space-based surveillance and reconnaissance capabilities.

While ISRO is yet to release complete details about the mission, available information indicates that the satellite will have a total mass of approximately 1,710 kg and will be placed into a sun-synchronous orbit at an altitude of around 529 km. It is expected that the satellite will take about three months to become fully operational post-launch.

Radar imaging satellites (RISAT) provide for all-weather surveillance. Normally, such satellites carry sensors like Synthetic Aperture Radar (SAR). Such sensors can capture very clear images of the targets on the ground during day and night. Also, the sensor functions perfectly even during the bad weather phase. Such satellites are known to offer valued military-related intelligence.

SAR technology helps armed forces in reconnaissance, surveillance, and intelligence gathering. In the Indian context, such technologies are of much use since India has unique terrain and topographic features. SAR helps in obtaining clear images along India’s geographical boundaries with neighbouring states, along seas, waterways, deserts, snowclad peaks, and forests.

India’s acquisition and subsequent development of RISAT has a long history and connects with India investing in satellite technology for its fight against terrorism. The impetus to acquire radar satellites was born after a major terror attack in November 2008 (26/11, Mumbai terror attacks). The country’s financial capital, Mumbai, witnessed 12 coordinated bombing and shooting attacks, which lasted over four days and killed more than 160 people. Because of the security challenges, an immediate need for reconnaissance satellites was felt, and India imported the technology from Israel.

India’s first radar satellite, called RISAT-2, was launched on April 20, 2009. It is important to mention that, at that point in time, ISRO was working on the development of SAR technology, and they were to launch RISAT-1 with an indigenous SAR sensor. However, owing to operational necessity, a satellite was purchased off-the-shelf from Israel.

Subsequently, on April 26, 2012, ISRO launched RISAT-1, equipped with an Indian-built Synthetic Aperture Radar (SAR). Subsequently, RISAT-2B and RISAT-2BR1 were launched in 2019. EOS-1 (also known as RISAT-2BR2) was launched on November 7, 2020, followed by EOS-4 (RISAT-1A) on February 14, 2022. Typically, such satellites remain operational for around five years, making it evident that India should be planning additional satellites in this series as replacements.

Starting with IRS-1A in 1988, ISRO has launched many operational remote sensing satellites. Currently, India has one of the largest constellations of operational remote sensing satellites. For some time now, ISRO has started placing different categories of remote sensing satellites under a single nomenclature called Earth Observation Satellite (EOS).

The RISAT-1B, which is expected to be launched on May 18, 2025, is also known as EOS-09. India’s EOS programme, managed by ISRO, involves launching satellites for various earth observation applications, including remote sensing, disaster management, and environmental monitoring. Key satellites in this series launched so far include EOS-01, EOS-06 (Oceansat-3), EOS-07 (Microsat-2B), and EOS-08, which has payloads like EOIR (Electro Optical Infrared Payload) for day and night imaging and a GNSS-R payload for remote sensing.

It is known that India’s remote-sensing satellite inventory is grossly insufficient for the country’s existing and future security needs. India shares boundaries with seven nations, stretching for more than 15,000 km on land and more than 7,500 km of coastline. Although India faces major challenges in managing its borders with Pakistan and China, keeping an eye on its other borders, particularly in the present-day context, the Bangladesh border is also important. Most of these borders are open borders, and intrusion can take place anytime.

However, despite such limitations, it is expected that India’s Defence Space Agency (DSA), which is known to control various space systems with military utility, has effectively leveraged available assets for reconnaissance and surveillance. This was evident from the various images released by the Indian Armed Forces showcasing battle damage assessments of all nine terrorism-linked targets. In addition to UAVs, satellites must have been employed to undertake these assessments.

For planning and executing such a complex operation, space-based systems must have been integral in providing real-time intelligence and situational awareness. Alongside the RISAT series, India also operates the Cartosat series of high-resolution Earth observation satellites capable of sending highly detailed imagery. These capabilities are crucial for identifying and monitoring specific targets such as terrorist camps and infrastructure.

Furthermore, satellites like GSAT-6 and GSAT-7 are known to support surveillance operations and fulfil critical communication requirements. Designed for network-centric warfare, they enable secure and reliable communication and can support joint missions by the Air Force and Navy, thus enhancing operational coordination and contributing to network-centric capabilities.

ISRO is also developing Geo Imaging Satellites (GISAT). They are imaging satellites put in geostationary orbit. The first satellite, EOS-3 (GISAT-1), was launched on August 12, 2021, but failed to reach orbit. During 2025, ISRO is expected to launch the second satellite in this series called EOS-5 (GISAT-2) for the Indian Navy.

It is unclear whether the immediate launch of RISAT-1B is a direct response to ongoing military challenges. Notably, earlier outlines of ISRO’s 2025 agenda made little to no mention of this satellite, suggesting that its launch may originally have been planned for a later date. Some years back, following the 26/11 terror attacks, ISRO had expedited the launch of RISAT-2.

Similarly, it is possible that the recent Pahalgam terror massacre and Operation Sindoor have prompted ISRO to fast-track the deployment of RISAT-1B. Regardless of the reason, RISAT-1B, equipped with a C-band Synthetic Aperture Radar payload, is expected to significantly enhance the Indian Armed Forces’ surveillance and reconnaissance capabilities.

The author is Deputy Director General, MP-IDSA, New Delhi. The views expressed in the above piece are personal and solely those of the author. They do not necessarily reflect Firstpost’s views.