BANGALORE, India — A turbo pump malfunction is being blamed for the April 15 launch failure of India’s Geosynchronous Satellite Launch Vehicle (GSLV).

The rocket veered from its flight path nearly five minutes after liftoff and crashed into the Bay of Bengal along with a communications satellite.

The Indian Space Research Organisation (ISRO) said July 9 that investigators traced the failure to a turbo pump malfunction that abruptly stopped the flow of liquid hydrogen fuel to the thrust chamber of the rocket’s domestically built third stage just 2.2 seconds after its ignition. ISRO said in a statement that investigators do not know for sure why the turbo pump failed but suspect that excessive pressure built up and thermal stresses produced “gripping at one of the seal locations” that caused a rotor to seize and rupture the turbine casing. A series of ground tests are planned to confirm the scenario, ISRO said.

The launch failure is a setback for India’s plans to attain self-sufficiency in cryogenic propulsion development. ISRO spent 3.3 billion rupees ($70.5 million) to develop the engine.

ISRO aims to flight test the upper-stage engine within a year “after incorporating necessary corrective measures,” the statement said. The next two GSLVs, meanwhile, will use Russian cryogenic stages.



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Based in Bangalore, Killugudi S. Jayaraman holds a doctorate in nuclear physics from the University of Maryland and a master's degree in journalism from the Medill School of Journalism at Northwestern University. He was formerly science editor of the...