ISRO has successfully tested its indigenously developed cryogenic engine in a major step forward for its landmark ‘GSLV Mk III’ rocket, scheduled for launch within the first quarter this year.ISRO has successfully tested its indigenously developed cryogenic engine in a major step forward for its landmark ‘GSLV Mk III’ rocket, scheduled for launch within the first quarter this year. Cryogenic engines are used in the upper stage of a rocket launch as they provide the maximum thrust to a launcher vehicle.The cryogenic upper stage, designated as C25, was tested on January 25 for 50 seconds at ISRO Propulsion Complex (IPRC) at Mahendragiri in Tamil Nadu, demonstrating all the stage operations, the space agency said.The performance of the stage during the test was as predicted, it said, adding that this was the first test in a series of two tests. The next one was planned for a flight duration of 640 seconds. The 50 second test is a significant milestone in the development of indigenous cryogenic propulsion technology, ISRO said, adding that the successful hot test of the stage in the first attempt itself demonstrates the agency’s ability to work in new areas like cryogenic technology.The development of C25 cryogenic stage began with the approval of GSLV MkIII, the next generation launch vehicle of ISRO, capable of launching 4 ton class spacecraft in Geosynchronous Transfer Orbit (GTO). The vehicle consists of two solid strap-on motors, one earth storable liquid core stage and the cryogenic upper stage. The C25 stage is the most powerful upper stage developed by ISRO and uses Liquid Oxygen and Liquid Hydrogen propellant combination.The stage carries 27.8 tons of propellants loaded in two independent tanks. The first flight stage for ‘GSLV MkIII-D1’ mission is in an advanced stage of realisation. It is scheduled to launch GSAT-19 during first quarter of 2017. The flight engine has been successfully tested in the High Altitude Test facility and integrated with the flight stage, ISRO said. ISRO said the C25 stage was conceptualised, designed and realised by Liquid Propulsion Systems Centre (LPSC), ISRO’s lead Centre for Propulsion, with support from various System Development Agencies from other three Centres of ISRO – Vikram Sarabhai Space Centre (VSSC), ISRO Propulsion Complex (IPRC) and Sathish Dhawan Space Centre (SDSC).