Facebook Twitter Google RSS

GAGAN GPS India: Satellite Launch to boost GPS in India

Bangalore: India will launch an advanced geostationary communication satellite April 15, using for the first time an indigenously built cryogenic engine in a heavier rocket and thus join the elite club of six countries, a top space scientist said Wednesday.

This will be followed by three more which will be part of Geo Augmented Navigational system (GAGAN) aimed at enhancing satellite signals to the levels needed for a GPS programme.

When the US prevented Russia from transferring its cryogenic technology to India in 1992, ISRO embarked on a mission to design and develop the cryo engine for achieving self-reliance in such complex technology..

"Technology denial has made us take up the challenge to develop our own cryogenic engine for launching heavier satellites in the higher orbits, about 36,000 km from the earth," Radhakrishnan recalled.

The efficient cryogenic rocket stage provides more thrust for every kg of propellant (fuel) it burns compared to solid and earth-storable liquid propellant stages. In the cooling engine, oxygen liquefies at -183 degrees centigrade and hydrogen at -253 degrees centigrade.

India, however, imported seven cryogenic engines from Russia but only used five of them to launch heavy satellites (above two-tonne class) in GSLV-Mark I and Mark-II rockets during the last decade.

The Indian-built cryogenic engine will be flight tested in the upper stage of the sixth geosynchronous satellite launch vehicle (GSLV-D3), carrying the geostationary experimental satellite (GSAT-4) from the ISRO spaceport at Sriharikota in Andhra Pradesh, 80 km northeast of Chennai.

"The lift-off is scheduled April 15 at 16.27 IST. The 416-tonne rocket with the GSAT-4 satellite has been moved to the second launch pad earlier in the day. The formal countdown for the launch will begin 29 hours before April 14," Radhakrishnan said.

The 2.2-tonne GSAT-4 will have one Ka-band regenerative transponder and a navigation payload that will operate in C-band and L1 and L5 bands for global positioning system (GPS)-aided geo-augmented navigation (Gagan).

For the state-run space agency, the cost of the launch will be Rs.175 crore (Rs.1.75 billion) and that of the satellite Rs.150 crore (Rs.1.5 billion).

Being an experimental mission and wholly funded by the Indian government, there is no insurance cover for the launch as well as the satellite.

As the third development flight mission, GSLV-D3 will deploy the experimental advanced technology communication satellite (GSAT-4) into the geosynchronous transfer orbit (GTO) 17 minutes after lift-off at 36,000km above the earth.

"As a technology demonstrator, GSAT-4 will enable the testing of many future communication satellite technologies. After reaching GTO, the satellite will use its own propulsion system to reach its geostationary orbital home and will be stationed at 82 degrees east longitude there," Radhakrishnan said.

Besides the cryogenic engine, the GSAT-4 has advanced telemetry system and advanced mission computers and larger composite payload faring.

The 50-metre tall four-tonne GSLV is a three-stage rocket with solid, liquid and cryogenic stages. The solid core motor of the first stage is one of the largest rocket motors in the world and uses 138 tonnes of propellant (fuel-oxidiser).

The second stage carries 38.5 tonnes of propellant and four strap-on motors of the first stage, with each carrying 42 tones of liquid propellant. The third or cryogenic upper stage carries 12.5 tones of liquid hydrogen and liquid oxygen as oxidiser.

"The satellite is jettisoned from the rocket at an altitude of 115km from the earth. The satellite and its electronics are protected by the composite carbon fibre-reinforced plastic payload fairing during its ascent through the atmosphere," the rocket scientist explained.

Featured Update

Nokia launches Nokia X, Nokia X+ and Nokia XL Android Smartphones

25 February 2014: Nokia has announced the launch of Android smartphones in the Mobile World Congress held at Barcelona, Spain. The company ...