GSAT-17, launched on an Ariane 5 rocket today, is the 31st communication satellite to roll off ISRO’s production lines.
The very first one was APPLE, the ‘Ariane Passenger Payload Experiment’, which the European Space Agency launched for free on their fledgling Ariane 1 rocket 36 years ago. This experimental spacecraft was, as an ISRO brochure noted at the time, “conceived as a stepping stone towards future operational national communication satellites which can provide communication, direct TV broadcast and meteorological services from a geostationary orbit.”
The first such operational communication satellite designed and built by ISRO, INSAT-2A, went into space, again on an Ariane rocket, in July 1992. (Before that, four INSAT-1 satellites were made for ISRO on contract by a U.S. company, then known as Ford Aerospace Communications Corporation.)
Of the 31 communication satellites that ISRO has turned out so far, 19 were sent on Ariane rockets, 10 on GSLV, 1 even on PSLV and, earlier this month, GSLV Mark III successfully launched its first such satellite. Three of the satellites that went on the GSLV were lost on account of launch failures and one had to be written off after becoming stranded in a lower-than-intended orbit.
As the graph above indicates, this year is likely to see ISRO launching a record five communication satellites. Three have already been sent into space in rapid succession: the GSAT-9 or South Asian satellite in May, followed by the GSAT-19 on the GSLV Mark III and now GSAT-17 this month.
The GSAT-6A, intended for the defence services, will go on a GSLV Mark-II rocket, possibly in September. GSAT-11, which will be the heaviest communication satellite built thus far by ISRO, weighing about 5.8 tonnes, is expected to be launched on an Ariane 5 rocket at the end of the year.
Author Details: Gopal Raj is a science journalist based in Thiruvananthapuram who has written extensively about the Indian space programme for over two decades and published a book, ‘Reach for the Stars: The Evolution of India’s Rocket Programme’. Follow him on Twitter @GopalRajN