CHENNAI: The reason behind the pressure in one of the strap-on booster motors of the GSLV flight on July 10 dropping to zero and the motor not developing enough thrust "is the point we have to go into in detail" during the failure analysis of the flight, said G. Madhavan Nair, chairman, Indian Space Research Organisation (ISRO).

He said he had appointed a high-power committee headed by K. Narayana to go into the failure of the GSLV-F02 (Geo-synchronous Satellite Launch Vehicle) that lifted off from Sriharikota on July 10 but plunged into the Bay of Bengal.

The committee would go into volumes of data, analyse it and submit a report within a month. The committee will comprise top ISRO engineers and members of national laboratories and academic institutions. Mr. Narayana retired as Director, Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh.

GSLV-F02 is made of three stages. Four strap-on booster motors, to augment the thrust of the rocket, are strung around the first stage of the vehicle, which is the core stage. The four strap-on engines are powered by liquid propellants, the first stage by solid fuel, the second by liquid fuel and the third topmost stage by cryogenic propellants.

Not "similar phenomenon"

Answering a question on thrust not developing in one of the strap-on motors of the first GSLV flight in 2001, the computer aborting the flight then and saving the vehicle, and why the computer did not halt the flight now, Mr. Madhavan Nair asserted that "it is not a similar phenomenon." In the GSLV's first flight, "the thrust did not build up to an adequate level (before the lift-off). Our computers detected it and stopped the flight. Here the thrust build-up was as expected. So we took a decision to go.

After the vehicle lifted off, the pressure in one of the strap-on engines dropped to zero. That is the point we have to go into in detail," the ISRO Chairman said. After the pressure in one of the strap-on engines dropped to zero, "it became impossible to save the vehicle."

Simulation

Top ISRO brass including Mr. Madhavan Nair; B.N. Suresh, Director, Vikram Sarabhai Space Centre, Thiruvananthapuram; M. Annamalai, Director, SDSC, tried to pinpoint on Tuesday how the whole sequence of events took place. "We did simulation," the ISRO Chairman said. The simulation showed how the pressure in one of the strap-on engines dropped to zero, how the thrust did not build up, the vehicle's consequent trajectory, the play of wind, how "the vehicle turned to one side" with the build-up of all these factors and crashed into the sea.

The GSLV-F02 was designed to withstand four degrees of angle of attack in its flight trajectory. With 10 degree of angle of attack, the vehicle broke up. "It withstood double the value of angle of error," Mr. Madhavan Nair said. But there was no control of the vehicle and it went down.

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