The failure of the GSLV is the third unsuccessful mission of the total seven of this indigenously-developed space rocket.
On April 15 2010, the third developmental flight of Geosynchronous Satellite Launch Vehicle (GSLV-D3) primarily for the flight-testing of indigenously-developed Cryogenic Upper Stage (CUS) could not accomplish the mission objectives. Like the GSLV (carrying INSAT-4C on board), which failed on July 10, 2006, Saturday’s rocket was also fitted with the Russian cryogenic engine.
Unlike the April 15 mission when Isro had faced anxious moments before the launch as it was the first time that the rocket was powered by the indigenous cryogenic engine, This mission was considered “routine” and Isro never expected trouble. The failure analysis committee comprising multi-disciplinary experts constituted by Isro to look into the April 15 failure concluded that ignition of the CUS main engine and two steering engines have been confirmed as normal, as observed from the vehicle acceleration and different parametres of CUS measured during the flight.
Vehicle acceleration was comparable with that of earlier GSLV flights up to 2.2 seconds from start of the CUS. However, the thrust build-up did not progress as expected due to non-availability of liquid hydrogen (LH2) supply to the thrust chamber of the main engine. This failure is attributed to the anomalous stopping of fuel booster turbo pump (FBTP). The start-up of FBTP was normal. It reached a maximum speed of 34,800 rpm and continued to function as predicted after the start of the CUS. —PTI