Setback for ISRO: PSLV mission fails again, deviates from path

The reason for Monday’s failure was not immediately known. But the previous failure, in PSLV-C61 in May last year, was attributed to an unexpected drop in pressure in the combustion chamber of the third-stage engine.

PSLV is ISRO’s mainstay rocket, having powered 65 of the 105 launches that India’s space agency has carried out till date. Only four of these, including the first one way back in 1993, have failed. But two successive failures within a span of six months does blemish an otherwise fine record. It could be embarrassing for ISRO if the reasons for Monday’s failure turned out to be similar to what happened with the previous mission.

It is the PSLV that is used for most of ISRO’s commercial launches, which bring in a lot of revenue as well as credibility. Five of the payloads on Monday’s mission were from Brazil, while one was from Nepal, the result of an India-Nepal collaboration. Another payload was from the United Kingdom. ISRO has launched more than 430 satellites from 34 countries until now, and is seen as one of the most cost-effective and reliable agencies for commercial launches. This is why Monday’s failure is a cause of major concern for ISRO.

It was nine minutes after the lift-off on Monday, after the successful completion of the first two stages, that the rocket began to deviate from its intended trajectory. The rocket had completed its vertical ascent and was beginning to get into an orbit around the Earth, a phase in which a big acceleration in velocity is expected.

“Close to the end of the third stage, we were seeing a little more disturbance in the vehicle roll rates, and subsequently a deviation was observed in the flight path. We are analysing the data and we shall come back at the earliest,” ISRO chairman V Narayanan said.

It is the second time in a row that ISRO has had a bad start to a year. Last year’s first launch, involving the navigation satellite NVS-02, had also run into trouble. At that time the problem was not with the rocket. The GSLV-F15 rocket had completed its job and placed the satellite in the geosynchronous transfer orbit. But the satellite’s own thrusters developed a problem after that because of which it could not be placed in the designated orbital slot.

ISRO carried out only five launches last year, including the hugely important and keenly awaited NISAR mission, the first of its kind collaboration with NASA.

This year, it was targeting at least six launches in the first quarter itself, including the first unmanned mission of the Gaganyaan human spaceflight programme. Monday’s setback can force a revision of this schedule.