Successful GSLV launch on Sunday important for ISRO

BANGALORE: Engineers at the Indian Space Research Organisation (ISRO) are never short of confidence. ISRO chairman K Radhakrishnan was oozing confidence before the Mars launch in November.

He is similarly upbeat now, two days before the launch of the Geostationary Launch Vehicle (GSLV) D5 — a rocket that launches a satellite at an altitude of 36,000 km — on Sunday. “We were confident in 2010 as well,” says Radhakrishnan, immediately putting things in perspective.

ISRO had two GSLV launches in 2010, and both were unsuccessful. The first one failed in April, milliseconds after the final cryogenic stage ignited. The second flight, in December, had to be destroyed just under a minute after lift-off as the flight path had deviated from predictions.

In August 2013, the flight had to be aborted an hour before lift-off, as the fuel tank developed a leak. This Sunday’s vehicle, named GSLV-D5, will put a satellite, called GSAT-14, into a geostationary orbit.

The rocket costs Rs 173 crore and the satellite Rs 45 crore. The GSLV will use an indigenous cryogenic engine in the third stage. India’s cryogenic engine, under development from early 1990s, has not had a full successful flight so far.

There were two successful GSLV flights earlier, but both had Russian engines. So GSLV-D5 is a high-stake flight for ISRO, much more valuable in commercial terms than the Mars Orbiter launch.

ISRO has spent considerable time in the last few years analysing the GSLV rocket and its failures. In 2010, an external committee headed by former chairman Madhavan Nair had looked into the matter first, and then an internal committee headed by SC Gupta, a former member of the Space Commission. Last year, another expert committee had cleared the GSLV for launch. It consisted of ISRO directors and aerospace professors from the Indian Institute of Science (IISc) and the IITs. Since then, the GSLV has gone through several modifications.

The booster turbo pump — which failed once — had different materials that contracted differently at low temperatures; they are made from one material now. The propellant acquisition device, imported from Russia, was found to be contaminated; it is now made in India. The casing has been modified as well. The vehicle has also undergone thorough testing.

In April 2013, ISRO modified its test facilities in Mahendragiri, in Tamil Nadu, for high altitude testing, and thus could do these tests on the GSLV. The fuel turbo pump has been tested in cryogenic conditions for the first time. The vehicle has also gone through about 850 wind tunnel tests to find out how it performs in different conditions.

So the GSLV-D5 is arguably the most tested vehicle of ISRO to fly so far. The success of the GSLV is critical for ISRO for many reasons. First, it has an aggressive internal satellite launching programme. As many as nine satellites are ready for launch. This includes the GSAT-6, 6A and 7A, the two remote sensing satellites GISATs, and the GSAT 9. Of course, there is Chandrayaan-2 getting underway soon.

A tested indigenous launcher is necessary for all of them. Secondly, ISRO is now keen to grab the rapidly-expanding international satellite launching market. Two years ago, market research firm Frost and Sullivan estimated that 927 satellites would be launched by 2020, including 405 communication satellites and 151 earth observation satellites.

All countries have been allotted orbital slots already, and most of them do not have launchers of their own. ISRO has a very mature rocket in the Polar Satellite Launch Vehicle (PSLV), but it can launch satellites only weighing just over a tonne (1,000 kg).

The weight of satellites has been increasing over time, and now satellites weighing over five tonnes are common. The GSLV, if it succeeds and develops well, can get a lucrative market of mediumsized satellites. “There is a market good between 3.5 and 5 tonnes,” says Radhakrishnan. It will have intense competition from other countries, especially China, which also has a heavy-lifter rocket. As usual, ISRO’s trump card will be the low cost of launch.