ISRO’s satellite mission fails due to dip in motor pressure

The Indian Space Research Organisation’s (ISRO) launch of Polar Satellite Launch Vehicle, PSLV-C61, aimed at deploying the earth observation satellite, EOS-09, into a sun-synchronous polar orbit from the Satish Dhawan Space Centre (SDSC), failed on Sunday owing to a fall in the chamber pressure of the motor in the third of fourth stage.

“Today 101st launch was attempted, PSLV-C61 performance was normal till second stage. Due to an observation in the third stage, the mission could not be accomplished,” ISRO said.

An internal committee of the space agency will look into anomalies and rectify, according to ISRO officials. ISRO chairman V Narayanan confirmed that the launch could not be completed due to drop in pressure.

“Today we targeted the launch of PSLV-C61 EOS-09 mission. The PSLV is a four-stage vehicle and up to the second stage, the performance was normal. In the third stage, the motor started perfectly but during the functioning of the third stage we saw an observation. There was a fall in the chamber pressure of the motor case and the mission could not be accomplished. We are studying the entire performance. We will come back at the earliest,” he said.

The high-performance stage 3 motor or HPS3 propulsion stage is a high-performance solid motor in ISRO’s PSLV. It provides additional thrust to further propel the payload towards its target orbit.

PSLV-C61 marks the 63 flight of the Polar Satellite Launch Vehicle and 101st space programme launch.

The mission would have placed the satellite into a Sun Synchronous Polar Orbit (SSPO), a type of polar orbit where a satellite is in sync with the sun. The satellites are placed in the SSPO for reconnaissance and security, to compare images over time to investigate how weather patterns emerge and monitor emergencies like forest fires or flooding.

At 450.790 km from earth, satellites usually eject from the PSLV launch vehicle allowing it to enter the intended orbits. E0S-09 was equipped with a Synthetic Aperture Radar (SAR) payload to deliver high-definition images for earth observation applications under all-weather conditions, significantly enhancing India’s surveillance capabilities.

This is the third failure of the PSLV mission since its inception in 1993. In September 1993, the PSLV-D1 was launched from Satish Dhawan Space Centre to place the remote sensing satellite. However, due to problems in the software, the mission failed.

Recently, in 2017, the PSLV flight was supposed to launch IRNSS-1H, the eighth satellite of the Indian Regional Navigation Satellite System (IRNSS). However, the payload fairing was not separated, which left the satellite trapped inside the rocket.

Former ISRO chairman Dr S Somnath said the ISRO’s team would dissect the anomaly.

Addressing the ISRO team, Somnath said, “We encountered a setback today during the PSLVC61 mission. Yet, true to its indomitable spirit, ISRO will swiftly assemble its finest minds to dissect the anomaly and chart a meticulous course forward. I am aware of the formidable challenges we faced during the development of the third-stage solid motor — an endeavour marked by multiple failures. It is indeed unusual to witness such anomalies resurfacing at this stage. Nevertheless, I have complete confidence that the team will identify the root cause both swiftly and effectively.”

He added that setbacks refine ISRO’s resolve and deepen its scientific rigour. “Nothing shall deter our pursuit of knowledge, which we carry forward with characteristic poise and unwavering precision,” Somnath said.