Why didn't the cryogenic engine ignite?

The non-ignition of the cryogenic engine on board the Geo-Synchronous Satellite Launch Vehicle (GSLV-D3) led to the failure of the mission on Thursday (April 15), the Indian Space Research Organisation (ISRO) has more or less concluded. “The cryogenic engine has not ignited, that is for sure. Why it has not ignited, the reasons have to be found out,” said S. Satish, ISRO spokesman, on Friday. All the telemetry data had come in by 1 p.m. on Friday and the ISRO top-brass was studying them line by line. The GSLV-D3 is a three-stage rocket and it was flying with an indigenous cryogenic engine for the first time. A cryogenic engine uses liquid hydrogen at minus 253 degrees Celsius as fuel and liquid oxygen at minus 183 degrees as oxidiser. The vehicle lifted off as planned at 4.27 p.m. and its performance was normal up to the end of its second stage till 293 seconds from the lift-off. But the vehicle developed problems when the cryogenic upper stage should have ignited 304 seconds after the lift-off, and it fell into the sea. An authoritative former ISRO official said: “It is very clear that the cryogenic engine did not ignite when you look at the curve [of the vehicle's trajectory], everything was normal up to the GS2 [second stage] shutdown. Then you can see clearly that there is no increment in the vehicle's velocity. The velocity is the same. It started losing its altitude also.”

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