ISRO&rsquo;s PSLV-C61 Mission Falls Short of Orbit: EOS-09 Surveillance Satellite Not Deployed After Third Stage Anomaly
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The Indian Space Research Organisation&rsquo;s (ISRO) much-anticipated PSLV-C61 mission, aimed at placing the advanced EOS-09 Earth observation satellite into a sun-synchronous orbit, was unable to complete its objective after an anomaly occurred during the rocket's third stage of flight.
The Polar Satellite Launch Vehicle (PSLV), India's workhorse launcher, lifted off as scheduled at 05:59 hrs IST from the First Launch Pad at the Satish Dhawan Space Centre (SDSC), Sriharikota. This was ISRO&rsquo;s 101st mission from the spaceport and the 63rd flight of the PSLV platform.
Initial flight performance of the launch vehicle was nominal, with the first and second stages &mdash; comprising the core PS1 stage and strap-on boosters &mdash; igniting and performing successfully. However, during the crucial solid-fuelled third stage operation, onboard systems registered a sudden drop in chamber pressure. As confirmed by ISRO Chairman Dr V. Narayanan, the anomaly led to the mission being deemed unsuccessful.
"Today, we were targeting the successful deployment of the EOS-09 satellite in a 500 km sun-synchronous orbit as part of the PSLV-C61 mission," said Dr Narayanan, addressing media following the launch attempt. "While the ignition of the third stage motor was confirmed, a fall in chamber pressure during its burn resulted in the mission not being accomplished."
Dr Narayanan, who previously led the analysis of the Chandrayaan-2 lander anomaly, affirmed that a comprehensive failure investigation would be undertaken. &ldquo;A detailed analysis is now underway. Both ISRO&rsquo;s internal Failure Analysis Committee and an external committee appointed by the Department of Space will examine all telemetry and performance data to determine the root cause of the anomaly,&rdquo; he added. Findings from these committees are expected in the coming weeks.
The EOS-09 payload aboard PSLV-C61 was intended to significantly enhance India&rsquo;s strategic surveillance and remote sensing capabilities. Equipped with a state-of-the-art Synthetic Aperture Radar (SAR), the satellite was engineered to provide high-resolution imagery irrespective of weather conditions or time of day, serving diverse applications such as border monitoring, disaster response, agricultural forecasting, urban planning, forestry and national security.
Had the mission been successful, EOS-09 would have joined ISRO&rsquo;s growing constellation of observation assets, complementing the existing fleet of CartoSATs and radar-imaging satellites, which continue to function in orbit.
In alignment with ISRO&rsquo;s ongoing commitment to responsible space operations, the mission architecture had incorporated an end-of-life disposal plan. A portion of the satellite&rsquo;s fuel was reserved to de-orbit the spacecraft after mission completion, ensuring a controlled re-entry and minimising long-term space debris.
The EOS-09 satellite, which was in development for over four years, will now require a replacement, a process likely to take several years given the intricate SAR payload and mission-specific specifications. The setback, while significant, is not expected to impact ISRO&rsquo;s upcoming schedule substantially, as the agency remains steadfast in its broader strategic and scientific agenda.
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EOS-09 satellite not deployed as ISRO’s trusted PSLV rocket faces third stage anomaly

ISRO’s PSLV-C61 Mission Fails During Third Stage

EOS-09 satellite not deployed as ISRO’s trusted PSLV rocket faces third stage anomaly

May 18, 2025 | 09:21 IST