A manufacturing error in an engine component caused the sudden loss of thrust in one of the four liquid propellent strap-on stages leading to the failure of the Geo-synchronous Satellite Launch Vehicle-F02 mission on July 10, the Failure Analysis Committee of the Indian Space Research Organisation has concluded.
The propellant regulator in question was supplied by an Indian company, one of the industry-partners of ISRO, and it was an 'inadvertent human error,' ISRO Chairman G Madhavan Nair told a news conference, where the findings and recommendations of the FAC were released.
The 15-member FAC, constituted to investigate the failure of the mission from Satish Dhawan Space Centre Sriharikota, concluded that all vehicle systems, except one strap-on stage, were normal until 56.4 seconds.
"The primary cause for the failure was the sudden loss of thrust in one out of the four liquid propellant strap-on stages (S4) immediately after lift-off at 0.2 seconds," concluded the FAC, chaired by K Narayana, former Director of SDSC SHAR, which reviewed the performance of GSLV-02 from lift-off to the end of flight.
The loss because of GSLV failure was put at Rs 250 crore -- ISRO spent Rs 150 crore to build the rocket, and another Rs 100 crore to fabricate INSAT-4C, which was to have been put in orbit by the GSLV.
But Nair said the firm, which supplied the faulty propellant regulator, which cost Rs 1 lakh, would not be black-listed and that the space agency will continue to source the component from the same supplier.
The Bangalore-headquartered
"It is not ISRO's culture to go on witch-hunting. It's not the time to say 'x' is faulty and 'y' is faulty. At ISRO, we own up the responsibility (for GSLV failure)," he said.
"We have to tell them (the company) they have to be stricter in future and not commit the error of this type."
He said ISRO will build an identical GSLV and a satellite similar to INSAT-4C for a launch in June next year.
According to ISRO, with only three liquid propellant strap-on stages working -- after the sudden loss of thrust in S-4 -- there was significant reduction in the control capability. However, the vehicle could be controlled till about 50 seconds. At the same time, the vehicle reached the transonic regime of flight and the vehicle attitude errors built up large values, resulting in aerodynamic loads exceeding the design limits thus leading to break-up of the vehicle.
The FAC has concluded that the design of GSLV is robust and recommended implementation of strict control on fabrication, inspection and acceptance procedures. Among others, FAC recommended fabrication processes to be critically reviewed and updated.
It has also recommended independent inspection of all critical dimensions of components and sub-assemblies by in-house agencies.
