ISRO has crossed yet another major milestone by successfully conducting the Flight Acceptance Hot Test of Indigenous Cryogenic Engine at Liquid Propulsion Systems Centre's (LPSC) Mahendragiri facilities on December 18, 2008. This Cryogenic Engine is identified for the first indigenously developed Cryogenic Stage to be used in the next Geosynchronous Launch Vehicle mission (GSLV -D3).

The indigenous cryogenic engine develops a thrust of 73 kilo Newtons (kN) in vacuum with a specific impulse of 454 seconds and provides a payload capability of 2200 Kg to Geosynchronous Transfer Orbit (GTO) for GSLV. The Engine works on 'Staged Combustion Cycle' with an integrated turbopump running at around 42,000 rotations per minute (rpm). It is also equipped with two steering engines developing a thrust of 2 kN each to enable three-axis control of the launch vehicle during the mission. Another unique feature of this engine is the closed loop control of both thrust and mixture ratio, which ensures optimum propellant utilisation for the mission.

The hot test was carried out for a planned duration of 200 seconds during which the engine was operated in the nominal and 13% uprated thrust regimes. All the propulsion parameters during the test were found satisfactory and closely matched with predictions.

The Cryogenic Engine will be further integrated with propellant tanks, stage structures and associated feed lines to realise the first fully integrated indigenous flight Cryogenic Stage by the middle of 2009.