India successfully tests indigenously developed high-thrust cryogenic rocket engine

India has successfully tested the first indigenously designed and developed high thrust cryogenic rocket engine, which generated a nominal thrust of 19 tonnes.

The engine successfully passed endurance hot tested for a duration of 800 seconds on 16 July 2015 at ISRO Propulsion Complex, Mahendragiri.

This duration is approximately 25 per cent more than the engine burn duration in flight. The engine will be used for powering the cryogenic stage (C25), the upper stage of the next generation GSLV Mk-III launch vehicle of ISRO, capable of launching four tonne class satellites, an official release said.

This cryogenic engine of C25 stage operates on Gas Generator Cycle using extremely low temperature propellants – liquid hydrogen (LH2) at 20 Kelvin (-253 deg C) and liquid oxygen (LOX) at 80K (-193 deg C).

The various subsystems of the engine comprise a regeneratively cooled thrust chamber, gas generator, LOX and LH2 high speed turbopump systems, flow control components, close loop mixture ratio control system, pyrogen igniters, fluid systems, etc.

The turbopump system rotates at a speed of 36,000 rpm with a power level of 2 MW.

This high performance cryogenic engine was conceived, configured and realised by the Liquid Propulsion Systems Centre (LPSC), the lead centre of Indian Space Research Organisation responsible for developing liquid propulsion systems for Indian Space Programme, the release stated.

The engine design was totally an in-house effort with experts from different fields like fluid dynamics, combustion, thermal, structural, metallurgy, fabrication, rotor dynamics, control components, etc, working together.

The fabrication of major subsystems of the engine was carried out through Indian Industries. Assembly and integration of the engine and testing were carried out at ISRO Propulsion Complex (IPRC), a unit of ISRO.

LPSC had also developed a cryogenic upper stage of 12.5 tonne propellant loading and successfully flight tested it in GSLV Mk-II vehicle on 5 January 2014. Compared to this stage, the C25 stage has a higher propellant loading (27 tonnes versus 12.5 tonnes) and higher engine thrust (19 tonnes versus 7.5 tonnes).

The latest endurance hot test of the first high thrust cryogenic engine is the tenth test in a series of tests planned and executed as part of the development of the engine employing complex cryogenic technology. The performance of the engine closely matches with the pre-test prediction made using the in-house developed cryogenic engine mathematical modelling and simulation software.

Prior to engine realisation, a series of subsystem level tests were carried out to independently evaluate the design of major subsystems like the turbopumps, thrust chamber, gas generator, flow control components, etc. Based on the confidence gained, the integrated engine testing was initiated.

As part of the C25 stage development, further tests are planned in high altitude conditions and in stage configuration, prior to the flight stage realisation.