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Monday 18 July 2011

ISRO-developed computer helped PSLV-C17 put satellite in orbit

Polar Satellite Launch Vehicle (PSLV-C17) mission that put the communication satellite GSAT-12 in orbit on Friday was that it used an indigenous computer, Vikram, with advanced software in the rocket's navigation, guidance and control systems, said K. Radhakrishnan, Chairman, Indian Space Research Organisation (ISRO). This advanced mission computer helped the rocket put the satellite accurately in orbit.


T.K. Alex, Director, ISRO Satellite Centre, Bangalore, said the coming days would be “interesting” because commands would be given from the Master Control Facility (MCF) at Hassan, Karnataka, to the liquid apogee motor (LAM) on board the GSAT-12 to take the satellite from its present sub geo-synchronous transfer orbit (GTO) to a circular geo-synchronous orbit at an altitude of 36,000 km. Dr. Alex was confident that the ISRO would do this with the experience gained from the Chandrayaan-1 mission in 2008, “which was almost similar” to the GSAT-12 mission.



S. Ramakrishnan, Director, Liquid Propulsion Systems Centre, ISRO, called Friday's success “yet another feather in the cap of the PSLV and the ISRO.”
A GSLV with an indigenous cryogenic stage would be launched from Sriharikota by June 2012, said P.S. Veeraraghavan, Director, Vikram Sarabhai Space Centre, Thiruvananthapuram.
Asked whether the PSLV-XL version would be used more often to put the ISRO's communication satellites in orbit than India's Geo-Synchronous Satellite Launch Vehicle (GSLV) or the Ariane vehicle of Arianespace, Dr. Radhakrishnan said the GSLVs were “more efficient and powerful” than the PSLVs. The GSLVs could put a 2.2-tonne communication satellite in a GTO but the PSLV-XL version could put only a 1.4 tonne communication satellite in a sub-GTO.
The GSAT-12, with its 12 extended C-band transponders, would boost ISRO's transponder capacity from 175 to 187. The ISRO had 211 transponders from its communication satellites at the beginning of the 11th Plan but it went down to 141 by April 2011 because of a series of failures with the GSLV flights. Dr. Radhakrishnan was confident that the ISRO's transponder capacity would go up to 215 by April 2012 with a series of launches of communication satellites from India and abroad. For instance, the GSAT-10, with 30 transponders, would be launched by an Ariane vehicle from Kourou island in French Guiana in April 2012.
An arbitration process would get under way between Antrix Corporation, the commercial arm of the Department of Space, and the Devas Multimedia Private Limited if the negotiations between the senior officials of the ISRO and Devas did not fructify, the ISRO Chairman said. (The ISRO annulled the allocation of 3G spectrum to Devas after allegations were made that the spectrum was sold to Devas at a low price). If arbitration was resorted to, the ISRO and Devas would each name an arbitrator of their own and these two would name another arbitrator. During the arbitration, which would take place in New Delhi, the Indian laws apply, he added.
“Good progress” had been achieved in realising the orbiter, lander and rover of the Chandrayaan-2 mission, slated to take place in 2014, said Mr. Alex. While India would make the orbiter and the rover, Russia would contribute the lander. The rover was undergoing tests in Bangalore on how to cross the obstacles on the lunar soil. Its engineering model would soon be ready.





This is the third time it is putting a satellite in a geo-synchronous transfer orbit; Chandrayaan-1 mission experience fruitful
India's Polar Satellite Launch Vehicle proved its versatility and reliability once again when the PSLV-C17 put the communication satellite GSAT-12 in a perfect orbit on Friday. The rocket roared off the second launch pad from the spaceport here on the dot at 4.48 p.m. and effortlessly lobbed the 1,310-kg satellite in orbit after a 20-minute eventless flight.
This is the 18th successful flight of the PSLV in a row and this is the third time that it is putting a satellite in a geo-synchronous transfer orbit (GTO), which is a tricky business. And the PSLV proved its versatility because it is the more powerful XL version of the PSLV that put the GSAT-12 in orbit. There are three versions of the PSLV — the standard, the core-alone without the six strap-on booster motors, and the XL version, which carries more solid fuel in its strap-on motors than the standard version. All the three versions have proved to be unalloyed successes. An XL version had successfully put Chandrayaan-1 in a GTO in October 2008.
There were thick clouds as the PSLV-C17 lifted off majestically and disappeared into the clouds after a few seconds. It was a flawless mission with the four stages of the PSLV-C17 igniting and separating on time and the fourth stage putting the satellite accurately in orbit.

“Important mission”

K. Radhakrishnan, Chairman, Indian Space Research Organisation (ISRO), called it an “important mission, both from the technological angle and for the people of the country.” The mission was so perfect that the rocket put the satellite in a sub-GTO with an apogee of 21,020 km against the planned 21,000 km and a perigee of 284 km against a targeted 281 km. The GSAT-12 with its 12 extended C-band transponders would be used in tele-medicine, tele-education, village resource centres and supporting disaster management. Though putting the GSAT-12 in a sub-GTO was “a tricky mission,” Dr. Radhakrishnan said, the ISRO was successful in doing it with the experience gained from the Chandrayaan-1 mission.
P.S. Veeraraghavan, Director, Vikram Sarabhai Space Centre, Thiruvananthapuram, called the PSLV “a proud symbol of ISRO's self-reliance.”
T.K. Alex, Director, ISRO Satellite Centre, Bangalore, said the GSAT-12's solar panels were deployed, they started rotating and commands were given to turn the panels towards the Sun to generate power.

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