GSLV launch went off the mark as 10 connectors snapped

The December 25 failure of geosynchronous satellite launch vehicle (GSLV)-F06 carrying an advanced communication satellite GSAT-5P occurred because of premature snapping of a group of 10 connectors located at the bottom of the Russian cryogenic stage.

These connectors carry command signals from the on board computer in the equipment bay, located near the top of the rocket, to the control electronics of the four L40 strap-on first stage boosters of the rocket.

These connectors are intended to be separated only on issue of a separation command at 292 seconds after lift-off. But the premature snapping of these connectors 47.8 seconds after the lift-off led to a stoppage of continuous flow of control commands to the control electronics, leading to loss of control and break-up of the vehicle.

This is the finding of the preliminary failure analysis team constituted by Indian Space Research Organisation (Isro) chairman K Radhakrishnan, and headed by former Isro chairman G Madhavan Nair.

The exact cause of snapping of the set of connectors is to be analysed.

Once the connectors snapped, the GSLV-F06 started developing errors in its trajectory and broke up 53.8 seconds after lift-off.

As per the norms, the range safety officer then issued a destruct command 64 seconds after lift-off to explode the rocket, and the mission was terminated when the rocket was still in its first stage of flight.