When India fires the high thrust cryogenic engine CE-20 to launch GSLV Mk III in its first experimental flight from Sriharikota on Monday, it will propel Isro's biggest dream albeit about 13 years later than it was originally planned. Isro would have used the CE-20 powered GSLV MkIII in 2003 if not for the US sanction and a foisted case. The launch, a culmination of a long and arduous journey spanning more than three decades, will set the ball rolling for Isro's future projects including Chandrayaan-2 and the manned mission. It will also be a first step towards setting its foot in the global heavy payload market.
Even as the Indian space agency struggled over the years to get a cryogenic engine for its heavy launch vehicles, the delay also helped it in mastering the technology. A cryogenic engine involves a tricky job of using liquid hydrogen at -253ºC and oxygen at -183ºC as fuel and oxidiser. Only the US, Russia, China, Japan and the European Space Agency have achieved this feat.
Isro began work to build indigenous cryogenic engine in the 1970s, though it gained momentum after Russia denied transfer of technology. But it was delayed as the space agency had to focus on their immediate requirements including development of Vikas engine, which now powers both PSLV and GSLV .
In the late 1980s the erstwhile Soviet Union offered three engines and a technology transfer at a reasonable price. Talks with Japan, US and Europe to borrow cryogenic technology had failed due to prohibitive costs. But after the collapse of the USSR in 1991, Russia backtracked on its pact.
Finally when Russia sent seven KVD-1 engines to India after redrafting the contract post the US sanctions, it was a mix of enthusiasm, confusion and uncertainty, as it was only a supply of hardware and not a technology transfer.
Isro launched a project to build a cryogenic engine in 1994 and the knowledge their engineers acquired through pilot projects like the development of a 12-tonne thrust engine, one-tonne and seven-tonne engines in the 1980s came in handy . According to Isro scientists, the engine CE-7.5 can be called an indigenous version, working on a staged combustion cycle, with Russian design.
While work to develop a high thrust CE-20 engine began in 2002, the technical issues of its predecessor delayed the project. On April 15, 2010, the engine failed 800 milliseconds after ignition during the launch of GSLV-D3 carrying GSAT-4 satellite. Isro used one of the last two Russian engines for their next launch, but the liquid fuel boosters failed. Another attempt at launch using an indigenous cryogenic engine on August 18, 2013 had to be aborted.
But developing CE-20 engine was equally challenging, as it was a completely new technology than CE-7.5.CE-20 engine was designed to provide double the thrust and lift double the payload weight than the previous engine.
Meanwhile, GSLV Mk--II tasted its first success in January 2004. With CE20, there were several tests that improved the design and analysis to make it flight ready