(This story originally appeared in on May 29, 2017)

NEW DELHI: The launch of indigenous rocket GSLV Mk III , which is said to be as heavy as 200 fully grown elephants, on June 5 would pave the way for India's first manned mission as it would make Isro capable of sending humans into space. Currently, only three countries--US, Russia and China-- have the capability of launching manned missions.Speaking to TOI, Isro chairman Kiran Kumar said, "GSLV Mk III could in principle be used for manned mission." GSLV Mk III, Isro's 'fat boy' as it is the country's heaviest (weighing 640 tonnes) but smallest rocket (43 metre), will have a new and advanced indigenous cryogenic engine to lift it off to the geostationary orbit. He said, "After over 200 tests have been done on different components of this heavy-lift rocket, we are targeting to launch this new vehicle on June 5."On the manned mission, which would cost the space agency billions of dollars, the Isro chairman said, "Until we get the final approval from the government, Isro won't work on the manned mission. Our key priority is to meet the national demand of providing more number of satellites into orbits in the field of communication, remote sensing and navigation. Therefore, we are focusing on increasing our launch capacities both in lower and geostationary orbits and to make our launches cost-effective."He added, "Till now, GSLV Mk II can put a 2.2-tonne satellite into the geostationary orbit. But GSLV Mk III can put a 4-tonne satellite into the geo orbit and even an 8-tonne satellite into the low earth orbit (LEO)."For the first time, the new cryogenic engine, which uses liquid oxygen and liquid hydrogen as propellants, is being tested on a fully functional rocket and it has taken Isro scientists over 15 years to master the technology of this engine. Gsat-19 satellite, which will be launched by GSLV Mk III, is a high throughput communication satellite that will help India fulfil its objective of increasing internet speed in the country.Tapan Misra of Ahmedabad-based Space Application Centre, said, "GSLV Mk III will have one of the world's heaviest sold motor engines and will have two strap-ons. This rocket is much more manoeuvrable than other rockets launched earlier and this feature will help us change its position in space."Development of the GSLV Mk III began in early 2000s, with the first launch planned for 2009-2010. Several factors had delayed the programme, including the April 15, 2010 failure of the Isro-developed cryogenic upper stage on the GSLV Mk II. A suborbital flight test of the GSLV Mk III launcher, with a passive cryogenic third stage, was successfully carried out on December 18, 2014, and was used to test a crew module on a suborbital trajectory.