Isro's 101st mission fails as PSLV-C61 suffers third-stage anomaly

Isro was unable to complete the launch of its Earth observation satellite EOS-09 aboard PSLV-C61 on Sunday due to an anomaly in the third stage of the four-stage rocket, investigation is underway

India’s latest Earth observation satellite mission faced a setback on Sunday morning. The Indian Space Research Organisation (Isro) launched its 101st mission, carrying the Earth Observation Satellite, named as EOS-09, aboard the Polar Satellite Launch Vehicle (PSLV-C61) rocket from the Satish Dhawan Space Centre, Sriharikota, at 5:59 am. It was to be put in a Sun Synchronous Polar Orbit (SSPO). However, Isro later confirmed that the mission could not be completed successfully.

 

The PSLV-C61, weighing 1,696.24 kg and standing 44.5 metres tall, marked its 63rd flight and 27th using the XL configuration designed for heavier payloads.  

 

 

Early launch smooth, but satellite fails to reach orbit

 

Isro was unable to complete the launch due to an anomaly in the rocket’s third stage. The space agency, in a post on X, said, "Today 101st launch was attempted, PSLV-C61 performance was normal till 2nd stage. Due to an observation in 3rd stage, the mission could not be accomplished." 

#WATCH | Sriharikota, Andhra Pradesh | ISRO Chief V Narayanan says, "Today we attempted a launch of PSLV-C61 vehicle. The vehicle is a 4-stage vehicle. The first two stages performed as expected. During the 3rd stage, we are seeing observation...The mission could not be… pic.twitter.com/By7LZ8g0IZ

— ANI (@ANI) May 18, 2025

 

Isro Chairman V Narayanan said, "The PSLV is a four-stage rocket, and its first and second stages performed as expected. The third stage motor ignited successfully, but an issue arose during its operation, preventing the mission from succeeding.”

 

He added, “We will return after conducting a thorough analysis.”

 

What is the EOS-09 mission?

 

EOS-09 is an advanced Earth observation satellite equipped with C-band synthetic aperture radar technology, This high-tech Earth observation satellite isn’t bothered by clouds, darkness, or bad weather, it snaps razor-sharp images of the planet’s surface 24/7. The all-weather, all-hours capability gives a major boost to India’s surveillance, environmental monitoring, and disaster management efforts across the board.  

 

EOS-09 is a follow-up to EOS-04, launched in 2022, and was designed to provide continuous remote sensing data to support operational activities and enhance observation frequency. 

#WATCH | Indian Space Research Organisation (ISRO) launches PSLV-C61, which carries the EOS-09 (Earth Observation Satellite-09) into a SSPO orbit, from Sriharikota, Andhra Pradesh.  EOS-09 is a repeat satellite of EOS-04, designed with the mission objective to ensure remote… pic.twitter.com/4HVMZzXhP0

— ANI (@ANI) May 18, 2025

 

The satellite carries deorbiting fuel for safe disposal at the end of its operational life. 

 

Post-deployment, the launch vehicle’s PS4 stage was intended to use Orbit Change Thrusters (OCT) to lower its altitude before undergoing passivation, an industry-standard process to reduce orbital lifespan and ensure responsible space operations.

 

Part of a satellite constellation

 

Earlier on Saturday, scientist W Selvamurthy congratulated Isro scientists, engineers and partner industries ahead of the launch. He noted that EOS-09 forms part of a wider satellite constellation used for agricultural, forestry, disaster management, and strategic applications. 

 

“EOS-09 is a crucial satellite within a constellation that monitors Earth and its changes. It supports areas like agriculture, forestry, disaster management, and strategic uses, especially in monitoring border regions,” Selvamurthy told ANI.

 

(With inputs from agencies)