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.
The EOS-09 carried a much-improved Synthetic Aperture Radar payload to provide images for various earth observation applications through thick clouds and at night. The SAR employs radar signals to create high-resolution images of terrestrial features, immensely benefiting environmental monitoring, emergency response, national security and military reconnaissance applications.
The mission failure came at a crucial juncture, that too with its much-trusted PSLV launcher, a go-to launch vehicle with a high success rate throughout its history since 1993. The Indian space programme is looking ahead at ambitious, high-stakes and costly missions—the main ones being the crewed space mission, Gaganyaan, in 2027; the launch of an indigenous space station, BharatiyaAntriksh Station, by 2035; and sending the first Indian astronauts to the Moon by 2040. These missions are more complex than the crewless PSLV-C61/EOS-09 mission, which involved parking the satellite in its sun-synchronous polar orbit and letting it serve its data users.
ISRO and the Union government may be aware that many of the future missions are high-stakes ones involving human astronauts, mandating zero-error operations. Going ahead, ISRO, India’s premier space agency, must ensure that its future mission paths have absolutely no room for errors or failures.