How the GSAT-12 and GSAT-8 satellite bring a major revolution in India’s communi­cations sector?

India on July 15, 2011 successfully launched its latest communication satellite GSAT- 12 onboard a powerful variant of homegrown Polar Satellite Launch Vehicle, PSLV-C17, from the spaceport.

In a textbook launch, Indian Space Research Organisation’s workhorse PSLV lifted off from the second launch pad of the Satish Dhawan Space Centre at Sriharikota at the end of the 53-hour countdown and placed the 1,410 kg GSAT-12 into orbit about 20 minutes later.

The launch vehicle injected the satellite very precisely into the intended orbit. On its 18th successful mission in a row, the PSLV zoomed into cloudy skies and successfully placed the satellite in the predetermined orbit. GSAT-12 was injected into an elliptical Transfer Orbit of 284 km perigee (closest point to Earth) and 21,000 km apogee (farthest point to Earth). Subsequently, the onboard Liquid Apogee Motor would be used to place the satellite in a circular orbit.

Advantage of GSAT-12

GSAT-12, the latest communication satellite built by ISRO, weighs about 1410 kg at lift-off. GSAT-12 is configured to carry 12 Extended C- band transponders to meet the country’s growing demand for transponders in a short turn-around- time.

The 12 Extended C-band transponders of GSAT-12 will augment the capacity in the INSAT system for various communication services like Tele-education, Telemedicine and for Village Resource Centers (VRC). GSAT-12 would also provide support for disaster management.

GSAT- 12 would be co-located with INSAT-2E and INSAT- 4A satellites. Launch of GSAT-12 is expected to partly meet the country’s growing demand for transponders in a short turnaround time. The mission life of the GSAT-12 satellite is about eight years.

The GSAT-12 satellite was built at a cost of Rs 90 crore. GSAT-12 will replace INSAT-3B, which was the first third-generation INSAT spacecraft to be launched. INSAT-3B was launched by an Ariane 5G rocket on 21 March 2000, and has already exceeded its ten year design life.

This was the second time in its 19 flights that the PSLV has been used for launching a communication satellite after Kalpana-1 in 2002. ISRO used the most powerful XL configuration with six extended solid strap-on motors carrying 12 tonnes of solid propellant as against nine tonnes for the standard PSLV for this flight. A similar configuration was used for launching India’s maiden Chandrayaan-1 lunar mission in 2008.

It is currently the most powerful PSLV variant in service. ISRO chose its reliable launch vehicle PSLV in the face of failures of two previous GSLV flights in April and December 2010 that dealt a blow to the missions to place GSAT-5 and GSAT-5P into orbit causing transponder shortage.

The uniqueness of the mission was the fact that a communication satellite was injected into the Geo Stationary Orbit using a polar satellite launching vehicle. Since the GSO is at a distance of 36,000 km from the earth, communication satellites are usually launched using high power Geo Synchronous Satellite Launching Vehicles. Since India is yet to perfect the cryogenic engine for powering the GSLV, ISRO opted for the PSLV. The PSLV C-17 mission saw the emergence of a woman scientist as the future face of India’s space programmes. Anuradha, a scientist from ISRO

Bangalore becomes the country’s first woman satellite fabricator. It was Anuradha and her colleagues which designed and built the GSAT- 12 satellite. The next PSLV-mission would launch MeghaTropiqe, a spacecraft jointly built by scientists of India and France.

Launch of GSAT-8

India’s communication satellite GSAT-8 was successfully launched on May 21, 2011 by Arianespace from Kourou in French Guiana to give a boost to direct-to-home services in the country. GSAT-8 was injected into space by European launcher Arianespace’s Ariane 5 rocket which lifted-off with Japan’s ST-2 spacecraft as co-passenger. Weighing 3,100 kg at lift-off, GSAT- 8 is one of the heaviest and high-powered satellites built by the ISRO.

ISRO’s Master Control Facility at Hassan near Bangalore has confirmed the reception of signals from GSAT-8 and taken charge of the command and control of GSAT-8 immediately after its injection into the geo-stationary transfer orbit. User community in India was looking forward for the operationalisation of the 24high-power Ku band transponders into the Indian National Satellite system.

ISRO said the launch was doubly gratifying as the space agency had lost two satellites last year in two unsuccessful GSLV missions launched from the home soil. ISRO was desperately looking to augment transponder capacity, which is in great demand. GSAT-8 carried 24 transponders to augment India’s Ku-band relay capabilities – primarily for direct-to-home TV broadcast services – with a coverage zone including the entire Indian subcontinent. Additionally, GSAT-8 carried the two-channel GAGAN system for aircraft navigation assistance over Indian airspace and adjoining areas.

French Guiana is a region of France on the North-East coast of South America. The successful launch has once again demonstrated the versatility and reliability of Indian space programme. This launch will argument communication networks in the country and help us meet the challenge of providing affordable radio and television connectivity and world class GPS services to millions of the countrymen.