A Preliminary Failure Analysis Team constituted to study the flight data of GSLV-F06, which crashed seconds after its launch on December 25, said that the primary cause of the failure was “the untimely and inadvertent” snapping of a group of 10 connectors located at the base of the Russian Cryogenic stage.
The premature snapping of these connectors stopped the flow of control commands to the core First Stage control electronics, leading to the loss of control and breakup of the vehicle, said a press statement from the Indian Space Research Organisation (ISRO) on Friday. The precise cause of the snapping of this set of connectors — whether due to external forces such as vibration or dynamic pressure — is to be analysed further, the statement added.
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Some of these connectors carried command signals from the onboard computer located in the Equipment Bay (near the top of the vehicle) to the control electronics of the four L40 strap-ons of the First Stage. These connectors were intended to be separated only during a separation command at 292 seconds after lift-off.
The performance of the GSLV-F06 flight (with GSAT-5P Satellite onboard) was normal up to 47.5 seconds from lift-off. The events leading to the failure began at 47.8 seconds after lift-off. Soon, the vehicle started developing “larger errors” in its orientation “leading to build-up of higher angle of attack and higher structural loads,” according to ISRO. The vehicle broke up at 53.8 seconds from lift-off. A “destruct” command was issued from the ground at 64 seconds after lift-off as per the Range safety norms.
The Preliminary Failure Analysis Team was chaired by the former ISRO Chairman, G. Madhavan Nair, and analysed the flight data along with members of the Launch Authorisation Board, the Mission Readiness Review Committee as well as senior functionaries of the GSLV Project and experts.
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The ISRO has now constituted a Failure Analysis Committee to carry out an in-depth analysis of the flight data of GSLV-F06 and data from the previous six flights of GSLV. The committee will establish reasons for the failure of GSLV-F06 and recommend corrective actions on the GSLV vehicle, including the remaining solitary Russian Cryogenic engine. The Failure Analysis Committee has 11 experts drawn from within ISRO and outside.
The ISRO has also constituted a Programme Review and Strategy Committee to look into the future of the GSLV Programme and the launches of the INSAT/GSAT Series, INSAT-3D and Chandrayaan-2. It will work towards the operationalisation of the indigenous Cryogenic Stage and come up with a strategy for meeting the demands of communication transponders in the immediate future, the statement said. This seven-member committee will be headed by K. Kasturirangan, former ISRO chairman.
These two Committees have been requested to submit their reports by the end of January 2011. The reports will be presented to eminent scientists and engineers, including A.P.J. Abdul Kalam, M.G.K. Menon, Yash Pal, U.R. Rao, K. Kasturirangan, Mr. Madhavan Nair, R. Chidambaram, and R. Narasimha.
“Internal exercise”
A panel chaired by S.C. Gupta, former member of Space Commission, will guide and facilitate an “internal exercise” by the ISRO chairman, and elicit “views from the ISRO community at all levels to gear up for the complex and challenging space missions ahead.”
The ISRO plans to complete these reviews and internal exercises by end of February 2011.