25-05-2025
- Science
- New Indian Express
Crewed missions ahead, Isro needs zero-flaw operations
The May 18 failure of India's workhorse Polar Satellite Launch Vehicle (PSLV) rocket to deliver sophisticated earth observation satellite EOS-09 to its intended orbit in space is a hard knock for the Indian Space Research Organisation (ISRO).
The four-stage PSLV-C61 launcher lifted off with the EOS-09 satellite sharp at 5.59 am from Satish Dhawan Space Centre, Sriharikota. The first two stages performed reliably, but the problem began after the third stage fired. The PSLV-C61 lost thrust, and the remaining third and the fourth stage (latter nestling EOS-09) crashed into the sea. ISRO Chairman V Narayanan suspects it happened due to a fall in pressure in the PSLV-C61's third-stage motor chamber carrying Hydroxyl-terminated Polybutadiene as the solid propellant.
Rocket propulsion experts understand that pressure in a rocket motor's combustion chamber can fall due to changes in the burning rate and surface area of the propellant or from issues within the nozzle, whether erosion or burning surface area. This caused a loss of thrust, preventing the PSLV-C61 from reaching the intended altitude of 534 km to release EOS-09 in its orbit and crashing about five minutes after launch.