Filling fuel for cryogenic engine to start

SRIHARIKOTA - Scientists were Thursday getting ready to launch an Indian-designed and built cryogenic engine to inject an advanced communication satellite into space. The filling of liquid fuel that will power the third stage of the 50-metre tall, 416-tonne Indian rocket to inject the satellite in geo-synchronous orbit is expected to start around 11.30 a.m.

The filling super cooled liquid hydrogen as fuel and liquid oxygen (oxidiser) for the cryogenic engine (12.5 tonnes) will continue minutes before the rocket blasts off from the second launch pad at the spaceport, around 80 km from here.

The rocket, Geosynchronous Satellite Launch Vehicle (GSLV-D3), is slated to inject GSAT-4, an advanced communication satellite into geo transfer orbit (GTO) Thursday evening.

“Preparations for fuelling the cryo engine is going on. Filling of liquid propellants in the second stage (40 tonnes) and the four strap-on motors (42 tonnes each) that will be hugging the rocket are over,” Indian Space Research Organisation (ISRO) director S. Satish told IANS from Sriharikota.

ISRO officials are confident of a smooth and successful launch, he said.

The countdown for the blast off for the Rs.330 crore mission (rocket Rs.180 crore, GSAT-4 satellite Rs.150 crore) started Wednesday at 11.27 a.m.

The first stage with 138 tonnes solid fuel is all ready to be fired up.

The rocket is expected to blast off at 4.27 p.m. Thursday to deliver the 2.2-tonne GSAT-4 satellite into GTO.

Queried about the Rs.20 crore cost increase for the rocket, the earlier one cost around Rs.160 crore in 2007, Satish said: “Compared to the previous GSLV rockets this is taller by one metre and weighs two tonnes more. The rocket has a bigger heat shield. One also has to factor the cost escalation aspects over the years.”

The notable aspect of this launch is that the rocket will be powered by ISRO-designed and built cryogenic engine (development cost around Rs.350 crore).

If the cryogenic engine performs as expected, India will become the sixth country in the world to design and develop the cryogenic technology.

The two other unique features of the rocket are its larger composite payload fairing or heat shield and the advanced telemetry systems and mission computers.

After a gap of several decades, the Indian space agency has reverted to fibre reinforced plastic (FRP) heat shield for its rocket.

The GSLV-D3 rocket has a bigger heat shield - four metre diameter - as compared to the earlier rocket versions whose heat shield were of 3.4 metre diameter and were made of aluminium alloy metal.