BANGALORE, India — An Indian Geostationary Satellite Launch Vehicle (GSLV) carrying a telecommunications satellite was destroyed about a minute after liftoff Dec. 25 after veering off course in the second straight failure involving that rocket.
The rocket, built by the Indian Space Research Organisation (ISRO), was engulfed in a ball of fire after an afternoon liftoff from Satish Dhawan Space Centre in Sriharikota on India’s southeastern coast. The accident cost an estimated 3 billion ($65 million) rupees — 1.25 billion rupees for the satellite payload and 1.75 billion rupees for the rocker.
On April 15 a GSLV failed to place a communications satellite into orbit. That mishap was attributed to a failure of India’s domestically developed cryogenic upper-stage engine, which was making its debut.
The latest failure occurred while the vehicle was still being powered by its solid-fueled first-stage, ISRO Chairman K. Radhakrishnan told a televised press conference soon after the accident. Radhakrishnan, who took the reins at ISRO in October 2009, said the vehicle lost control 47 seconds after liftoff and started deviating from the flight path. He said the rocket was destroyed on command at about 63 seconds into the flight when it was at a height of about 8 kilometers and 2 kilometers down range.
Radhakrishnan said controlling commands from the vehicle’s on-board computer did not reach the actuators in the first stage, perhaps because the connector failed. “Why it happened, we have to find out,” he said.
One source, who has been associated with ISRO’s launch vehicle program for two decades, was skeptical. “If you had seen the connectors you will realize it can’t snap just like that,” he told Space News Dec. 27. “The connectors are so well locked they cannot snap unless the vehicle itself breaks.”
This source speculated that the weight of the payload — the 2,310-kilogram GSAT-5P satellite was the heaviest to launch aboard a GSLV — was a factor in the mishap.
“My analysis is the vehicle broke as it was not capable of taking the higher structural load brought about by tilting beyond the limit (plus or minus 4 degrees) of controllability due to excessive payload weight,” the source said. “It is possible the analysis by our scientists to look at vehicle stability after increasing the payload weight had gone wrong somewhere.”
The source pointed out that failures had never occurred before with the GSLV’s first two stages, which have been tested and proven. “It is the first time failure has occurred in the first stage and in this case the only difference is in higher payload,” the source said.
The GSLV launch — seventh of the vehicle since 2001 — originally was scheduled for Dec. 20 but was postponed after a leak was detected in one of the valves of its Russian-built cryogenic upper-stage engine. ISRO gave the go-ahead for a Christmas-day launch after concluding the leak was not serious.
Of the six previous launches of GSLV only two were totally successful, with two partial successes.
The GSLV rocket is 51 meters tall, weighs 418 tons and has three stages. The first stage is powered by a solid-fuel motor with four strap-on boosters providing additional thrust during lift-off and the initial phase of flight. The second stage is powered by a liquid-fueled engine while the third stage uses liquid hydrogen as fuel and liquid oxygen as oxidizer.
ISRO spokesman S. Satish told Space News that telecommunications services in India will not be affected by the launch failure as there are eight Insat communication satellites in operation. Another satellite, GSAT-8 with 24 transponders, is to be launched by the European Ariane 5 rocket in March or April 2011, he said.
Satish also played down concern that ISRO’s second Moon mission, Chandrayaan-2 would be affected by the failure. He said the problems with the GSLV would be resolved by 2013 when that mission is slated for liftoff.
ISRO has just one Russian cryogenic upper-stage engine for the GSLV remaining, part of a multi-engine deal that dates back to the 1990s. India’s indigenous cryogenic upper-stage engine is not operational yet.
