Scientists at the Indian Space Research Organisation were set to launch their heaviest satellite to retire an old one sent up in 1999 and ensure continuity of telecom, TV and weather services, officials said. The satellite, officially called GSAT-5P, will blast off on the state-run space agency’s geosynchronous satellite launch vehicle, or GSLV, and scientists hope they will be three times lucky in the seventh such attempt they will make on Monday.
“Everything is normal and going as per schedule,” said S. Satish, the agency’s director for publications and public relations. “The rocket’s full system scan went off well and we are now gearing up for a launch-rehearsal Friday,” said Satish. “If the scientists are satisfied with the rocket’s condition then a final clearance for the flight will be given,” another official said, adding that the final countdown is slated for Dec 20 from Satish Dhawan Space Centre in Sriharikota. The launch vehicle is 51 metres tall, weighs 418 tonnes and costs around Rs.175 crore (Rs.1.75 billion). The satellite, with a payload of 2,310 kg, has a price tag of Rs.125 crore. ISRO has till date sent up six GSLV rockets with satellites, of which only two missions were full successes and one a partial victory. The rest could not accomplish their mission of slinging the satellite into their intended path of orbit.
The two successful launches were in 2003 and 2004, and put into space an experimental communication satellite GSAT-2 and another for educational purposes Edusat. The Dec 20 launch is to replace Insat2E that was intended to cater to Asia and Australia. The Dec 20 launch is also the first time ISRO is sending up its geosynchronous satellite launch vehicle in December. The earlier launches were in April with two flights in 2001 and 2010, September with two in 2004 and 2007 and one each in May 2003 and July 2006. According to officials, the rocket’s maiden flight in 2001 could not attain success as it was not able to sling its satellite, GSAT-1, into the intended orbit. In 2006, the agency had to destroy its rocket mid-air for the first time in the agency’s history.
The 2007 flight was considered a partial success and the April 2010 flight carrying the GSAT-4 satellite is considered historic as the rocket’s cryogenic engine, too, was made in-house by the space agency. They were using Russian-made cryogenic engines earlier. The Dec 22 launch will again be on a Russian engine.
Unfortunately, the April 2010 mission failed as the rocket fell into the Bay of Bengal due to a malfunction in the indigenous cryogenic engine. ISRO chairman K. Radhakrishnan had then said the next launch with an Indian engine will be within a year. Over the years, the carrying capacity of the geosynchronous satellite launch vehicle has also increased — from 1,530 kg in 2001 for GSAT-1 to 2,220 kg for GSAT-4 in April 2010. The latest has a payload of 2,310 kg, with 36 transponders — an automatic receiver and transmitter of communication or broadcast signals. A successful launch of the satellite will take the agency’s transponder capacity to around 235 from 200 in orbit now.