The Hindu Business Line : Next GSLV will be powered by an Indian cryo

Chennai, Sept. 6 The cryogenic engine that powered the GSLV rocket launch on Sunday was the fifth of the seven that Russia had sold to India. The Indian Space Research Organisation (ISRO) has two more of the Russian-make, but since the indigenous engine is getting ready, the next GSLV may be fired by an Indian cryogenic engine.

Also, the next cryogenic engines used will pack more punch — 9 tonnes of thrust against 7.5 tonnes of the hitherto launched five Indian GSLV rockets. Scientists at ISRO will squeeze in more liquid hydrogen and oxygen — 15 tonnes instead of 12.5 tonnes. They could do this by being able to cool the liquids half a kelvin more (21.3 K), so as to compensate the inevitable rise in temperature when more fuel is packed.

The higher thrust has a direct implication on economics — the rocket will be able to carry about 200 kg-heavier satellite, which means that more of commercial material, such as transponders, could be packed in.

The step-function jump in satellite capacity will be achieved when ISRO is able to deliver the completely new GSLV Mark III, which will be able to carry a 4,000-kg satellite. The GSLV that was launched on Sunday carried a satellite that weighed 2,140 kg.

Mr Gnanagandhi, former Project Director, Indigenous Cryogenic Project, who was present at the launch event, told Business Line that the indigenously developed engines have been successfully tested for 500 seconds, long enough to put them into rockets. Mr Gnanagandhi is currently Programme Director, Directorate of Quality and Reliability, ISRO.

The cryogenic engines—which hold 11 tonnes of liquid oxygen and 2.5 tonnes of liquid hydrogen at extremely cold temperatures — are tough to make and a challenge to handle.

These liquids are held in aluminium tanks with a 36 mm polyurethane foam and another 12 protective thin layers of insulation, including a heat resistant paint.

Still some heat will get in, causing the liquid to vapourise. Until about an hour before the rocket is launched the vapours will be let out and fresh liquid fuel let in, Mr Gnanagandhi explained.