ISRO is developing a high thrust cryogenic engine to be used for the upper stage of its heavy lift launch vehicle GSLV Mk-III. This high thrust cryogenic engine produces a nominal thrust of 196.5 kN in vacuum with a specific impulse of 434 seconds. The engine works on “Gas Generator Cycle” which has flexibility for independent development of each sub-system before the integrated engine test, thus minimising uncertainty in the final developmental phase and reducing development time. This engine generates nearly 2 MW power as compared to 1 MW generated by the engine of Cryogenic Upper Stage (CUS) engine of GSLV. The high thrust cryogenic engine is one of the most powerful cryogenic engines of upper stages in the world.

ISRO has achieved a major milestone by successfully conducting the ground test of Indigenous High Thrust Cryogenic Engine at ISRO Propulsion Complex at Mahendragiri on April 28, 2015 at 1657 Hrs for a duration of 635 seconds. All the propulsion parameters during the tests were found satisfactory and closely matched with predictions. This ground test was preceded in the last few weeks, by four short duration tests of 5.5, 7.5, 20 and 30 seconds.

The high thrust cryogenic engine is designed and realised by Liquid Propulsion Systems Centre (LPSC) at Valiamala with the support of Vikram Sarabhai Space Centre (VSSC) at Thiruvananthapuram. The engine assembly, integration and testing is carried out by ISRO Propulsion Complex (IPRC) at Mahendragiri. Indian Industries have significantly contributed in the realization of the cryogenic engine.

While ground tests conducted so far validate this the design adequacy and performance of the integrated engine, further demonstration tests are planned at engine and stage level to characterise the different performance parameters under various operating conditions. After completion of the tests, the indigenous high thrust cryogenic engine and stage are planned to be flight tested in GSLV Mk- III-D1 mission.