ISRO space missions NVS-02 and PSLV-C61 face setbacks in 2025

In an unusual back-to-back setback for India's space agency, ISRO, both space missions undertaken in 2025 have encountered serious trouble. On Sunday, 18th May, barely eight minutes after liftoff, ISRO halted the live stream of the PSLV-C61/EOS-09 mission. As per initial information, the four-staged rocket encountered trouble mid-flight. "Up to the second stage, performance was normal. The third stage ignited, but we observed its functioning. The mission could not be accomplished. We are studying the data," said ISRO Chief Dr. V. Narayanan towards the end of the official live stream.

Over a dozen Indian Parliamentarians, who are part of the Parliamentary Standing Committee of Science and Technology, were at the spaceport in Sriharikota to witness ISRO's 101st rocket launch mission. Notably, the PSLV is ISRO's most-flown rocket and has a great track record of launching over two hundred satellites belonging to India and foreign customers. In its 63 launch missions to date, this is the third failure of the PSLV. Addressing journalists at the spaceport, the ISRO Chief elaborated on the observations. "The third stage of the PSLV uses a solid-fuel motor system. There was a fall in the chamber pressure in the motor case. We are studying the entire performance," Dr. Narayanan said.

EOS-09 is a radar imaging satellite(earlier known as RISAT) that is capable of day and night imaging. It can see through clouds, deliver images under all weather conditions. This 1,700kg satellite was meant to have an operational life of at least five years. Ideally, the EOS-09 satellite should have been placed in its designated orbit, almost 18 minutes after liftoff.

Radar imaging satellites are unique because they do not take pictures like a conventional camera-carrying satellite. Instead of giving an optics-based picture(like a photograph), the RISAT beams radar waves onto the Earth. The features on the Earth's surface (buildings, trees, mountains, water bodies, roads) reflect these radar waves back to the satellite. It is by collecting and processing the reflected radar waves that RISAT can provide the end product, which is round-the-clock, all-weather imagery. While conventional Optical satellite images are in colour, radar satellite images are inherently black and white.

The launch of this strategic satellite comes a week after Nuclear-armed neighbours India and Pakistan announced a ceasefire, following three days of a rapidly escalating war-like situation. However, it must be emphasised that the space launch mission taking place at this time is a mere coincidence. The PSLV rocket takes a little over a month to assemble, and it takes well over a year to build a satellite like EOS-09. At the Indian Spaceport, the preparations for this launch are said to have commenced in mid-March, more than a month before the situation between India and Pakistan deteriorated.

Following the April 22nd Pahalgam terror attack in Jammu and Kashmir, ISRO Chief Dr. V. Narayanan had cited the need for launching 100-150 satellites to keep a constant vigil over India's 7,500 km long coastline and 15,000 km long land borders.

At present, India operates multiple satellites for strategic purposes, this includes the Cartosat series of satellites, the RISAT(Radar imaging satellites) series, EMISAT etc. In addition to this, there are large communication satellites such as GSAT-7 that caters to the Indian Navy and the GSAT-7A that caters to the Indian Air Force and Strategic Forces Command.

Strategic satellite NVS-02 faced a setback in February 2025

In February 2025, ISRO announced that its NVS-02 satellite, which is meant to serve strategic purposes, remains stuck in an initial orbit, and it has not been possible to move it to its intended orbit. Satellites have to be placed in their precise orbital slots to perform their designated role. After the announcement of the setback in February, ISRO had not provided any further updates.

Satellites are moved from one orbit to another by firing their liquid-fuelled engines that burn a fuel and oxidiser combination. In this case, it had not been possible to fire the engine and raise the satellite's orbit, due to a suspected electrical issue with the valve that releases the oxidiser. The 2,250kg NVS-02 satellite was launched by a GSLV-Mk2 rocket on January 29th, in what was ISRO's 100th rocket launch mission from the country's premier Sriharikota spaceport.