Indian Space News and Discussion

[sai_k]

http://flonnet.com/stories/20100521271010100.htm

Cryogenic setback



K. Radhakrishnan, Chairman, ISRO: “We will put all our efforts to ensure that the next GSLV flight with an indigenous cryogenic engine takes place in a year.”



At 4-27 p.m., the vehicle rose from the launch pad and sped into the sky, riding on plumes of flame and smoke. The four liquid strap-on booster motors surrounding the core first stage ignited on time. The first stage, fired by solid propellants, then came into play even as the strap-on booster motors fell away. The first stage jettisoned 151.6 seconds after lift-off. The second stage, powered by liquid propellants, ignited at 151.7 seconds. The payload fairing, which protects the satellite and the vehicle’s electronics from intense heat during the vehicle’s ascent into the atmosphere, separated down its seams and fell into the Bay of Bengal 228.8 seconds from blast-off. The second stage shut down at 293 seconds. The cryogenic engine ought to have ignited at 304.9 seconds and burned for the next 720 seconds to provide the necessary velocity to inject GSAT-4 into the intended GTO.



It was clear that the cryogenic engine had not ignited. The rocket was losing velocity and altitude, and soon it veered off its path and plunged into the sea. As the vehicle’s trajectory fell within the safety corridor, the Range Safety Officer did not press the “destruct” button to destroy the rocket.



The cryogenic engine ignition occurred as planned, he said, but added: “This needs to be confirmed after a detailed analysis of the data.” According to Radhakrishnan, the vehicle was seen tumbling and losing control, “most probably because the two vernier engines [in the cryogenic engine] could not ignite”. (The vernier engines, also called steering engines, control the roll, pitch and yaw of the vehicle in flight.)