Chennai: The decision to destroy the geo synchronous launch vehicle F 02 (GSLV F02) was taken independently by a small group of three safety officials in the Satish Dawan Space Centre (SDSC).
Located away from the mission control room, the group monitors the flight path diligently plotting the Instantaneous Impact Point (IIP)-the point where the vehicle or its debris would fall. According to an official of Indian Space Research Organisation (ISRO), the group is totally independent and does not need to get prior sanction to destruct the vehicle if required.
On July 10, 2006, when the group saw the GSLV F02 going awry, the leader of the group pressed the "destroy" button. Forty-five seconds after GSLV F02 lifted-off, it was destroyed when it went out of control. "The vehicle at that time was 15km over the sea and the debris would not have fallen on land even if the vehicle was not destroyed," said an official.
The GSLV F02 is a three-stage vehicle. The first stage (GS1) comprises a core motor with 138 tonnes of solid propellant and four strap-on motors each with 42 tonne of hypergolic liquid propellants (UH25 and N2O4).
The second stage (GS2) has 39 tonnes of the same hypergolic liquid propellants. The third stage (GS3) is a cryogenic stage with 12.6 tonnes of liquid oxygen and liquid hydrogen.
As per the original flight plan, the GS1 - the first stage - should burn out in 149.7 seconds at an altitude of 70.4km when the vehicle is moving at a velocity of 2.8km per second. The heat-shield separation is at 228.9 seconds (altitude 115 km, vehicle speed 3.9km per second), the GS2 burnout at 290.6 seconds (131.9km, speed 5.4km per second), GS3 burnout at 1,002.5km (220.2km, speed 10.2km per second) and the satellite separates 13 seconds after that.
But within 45 seconds of the take off the vehicle went off its path and also did not develop the required speed. So at the time of destruction, the second- and third-stage fuel and also the fuel in the satellite must have exploded resulting in a huge flame ball. Had it not been for the overcast sky, the spectacle would have been visible from the earth.
also see : ISRO forced to destroy
GSLV in mid air