Faulty connectors and cables were the cause of the 25 December failure of the Geostationary Satellite Launch Vehicle (GSLV), the second of 2010 for the Indian Space Research Organisation, a space agency panel has determined.
The "untimely and inadvertent snapping" of a group of 10 connectors at the bottom of the rocket's Russian-supplied upper stage caused the on-board computer near the top of the GSLV to lose communications with the control systems for the four L40 strap-on boosters that augment the rocket's first stage.
The connectors are built to snap apart on command, 292s after lift-off, but, for reasons still being investigated, they broke early. The GSLV flight was normal until 47.5s after lift-off, but from there the rocket lost orientation and began to break up under stress at 54s. A self destruct command was sent from the ground station 64s after lift-off.
An additional seven-member panel, led by former ISRO chairman K Kasturirangan, has been set up to examine the future of India's GSLV programme, including forecasting the vehicle's reliability for the Chandrayaan-2 mission to the Moon, scheduled for 2013.
Results from both the launch and programme reviews are expected at the end of February, says the ISRO.
During April's failed launch attempt, the performance of the GSLV-D3 vehicle was normal through the second stage. After a 293s burn of the first two stages, the cryogenic stage was supposed to ignite and burn for about 720s, sending the GSAT-4 satellite into the intended geosynchronous transfer orbit. The third stage never lit and the vehicle tumbled, lost altitude and eventually splashed down in the sea.
In the past decade, the GSLV has failed in four out of seven launch attempts.