GSLV

India will soon launch an advanced communications satellite, put into orbit for the first time by a cryogenic engine developed by its own scientists.GSLV-D3 carrying GSAT-4 satellite is scheduled for launch on April 15, 2010 

Cryogenic engines are rocket motors designed for fuels that have to be held at very low temperatures to be liquid. They would otherwise be gas. Officials say that only five countries in the world have this technology.

GSLV-D3 is the third developmental mission of India's Geosynchronous Satellite Launch Vehicle during which ISRO's indigenously developed Cryogenic Upper Stage (CUS) will be flight tested. In this flight, GSLV is scheduled to launch 2220 kg GSAT-4, an experimental advanced technology communication satellite that carries communication and navigation payloads, into Geosynchronous Transfer Orbit (GTO). GSLV, carrying the indigenous CUS, is designated as GSLV MkII. Envisaged mainly as a technology demonstrator for advanced satellite communications, GSAT-4 will enable the testing of many future communication satellite technologies. After reaching GTO, GSAT-4 will use its own propulsion system to reach its geostationary orbital home and will be stationed at 82 deg East longitude there.

GSLV-D3 is the maiden flight of GSLV in which the indigenous Cryogenic Upper Stage (CUS) is used. In the past five flights of GSLV, Cryogenic Stages (CS) procured from Russia were used. GSLV, with the Russian CS, was designated as GSLV MkI, whereas the present GSLV carrying the indigenous CUS is designated as GSLV MkII.

Cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to the use of propellants at extremely low temperatures and the associated thermal and structural problems. Oxygen liquifies at -183 deg C and Hydrogen at -253 deg C. The propellants, at these low temperatures, are to be pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of the cryo fluids and related safety aspects.

A befitting Reply to Denial regimes

India began developing cryogenic technology after Russia reneged on a deal to supply cryogenic engines in 1993 - following pressure from the United States, which believed India was using the technology to power missiles. 
 

Asked at a press conference , if Russians were involved in the development of cryogenic technology, ISRO Chairman K Radhakrishnan said India certainly learnt a lot working with Moscow and it was a "good learning experience".

But he asserted: "The (cryogenic) engine is designed by our own engineers, our own industry fabricated it, tested...". He added: "It's Indian. You should be proud of it".
 

Dr Radhakrishnan told reporters in Banglalore that the technology was home grown because "one country stopped another country in giving this technology to India".

"The best reply is to... build your own technology," Dr Radhakrishnan said.India has been using Russian engines to launch heavier satellites into space for some time. It joins the US, Russia, Japan and China in having developed cryogenic engines.

India's Geo Satellites

GSAT-4 is the nineteenth Indian geostationary satellite built by ISRO. In the past two and a half decades, India's geostationary satellites have revolutionised the country’s telecommunications, TV broadcasting and Weather Monitoring sectors. More recently, ISRO's INSAT and GSAT series of satellites circling the Earth in the 36,000 km high geostationary orbit have brought in a revolution in India's healthcare and educational sectors. Besides, they have been instrumental in taking the benefits of space technology directly to the doorsteps of rural India through Village Resource Centres (VRCs). Today, geostationary satellites are an integral part of India's national infrastructure. The country has about 200 communication transponders in geostationary orbit that operate in S, C, Extended C and Ku bands.

The ISRO chairman said the PSLV mission, which would launch Cartosat-2B, an Algerian satellite, two Canadian nano-satellite, and Studsat developed by Indian students, is slated in the first half of May.

If it turns out to be a success, India hopes to emerge as a global player in the multi-billion dollar satellite launch market.