Snapping of connectors led to rocket’s failure

BANGALORE/CHENNAI - The snapping of connectors carrying command signals has been found to be the primary cause of India’s rocket failure on Christmas day, the space agency said Friday.

“The inadvertent snapping of 10 connectors carrying command signals from the onboard computer to the control electronics of the four strap-on motors in the first stage is the primary cause of the rocket failure,” the state-run Indian Space Research Organsiation (ISRO) said in a statement.

The connectors are located beneath the Russian-made cryogenic engine, which was in the upper/third stage of the 418-tonne geosynchronous satellite launch vehicle (GSLV-F06), carrying the 2.3-tonne GSAT-5P communication satellite with 36 transponders.

The onboard computer resides in the equipment bay near the top of the rocket. The connectors were to separate on issue of a separation command at 292 seconds (4.87 minutes) after lift-off.

The premature snapping of the connectors stopped flow of control commands to the first stage control electronics and led to loss of control and break-up of the vehicle.

“The exact cause of snapping of the connectors, whether due to external forces like vibration, dynamic pressure is to be analysed and pin-pointed,” the space agency noted.

When the rocket began disintegrating within a minute after a smooth lift-off from the spaceport Sriharikota in Andhra Pradesh, about 80 km north-east of Chennai, a destruct command was given by the mission control centre to prevent the debris falling on the land though it was 8 km in the sky and 2.5 km away from the coastline over the Bay of Bengal.