Indigenous cryogenic stage successfully qualified

Indigenous cryogenic stage successfully qualified

Bangalore: India has successfully tested the indigenously developed cryogenic stage to be employed as the upper stage of the country’s Geosynchronous Satellite Launch Vehicle (GSLV) in a significant milestone in its space programme.

The test was conducted for its full flight duration of 720 seconds Thursday at Liquid Propulsion Test Facility at Mahendragiri in Tamil Nadu, Indian Space Research Organisation (ISRO) said.

“With this test, the indigenous Cryogenic Upper Stage has been fully qualified on the ground. The flight stage is getting ready for use in the next mission of GSLV (GSLV-D3) in 2008", the Bangalore-headquartered space agency said in a statement today.

A ground test for 480 seconds of the complete stage was conducted on August four last year, it said.

ISRO said the successful ground test of the indigenous cryogenic upper stage (CUS) for the full flight duration has validated the design robustness and performance adequacy for its use in GSLV.

The indigenous CUS is powered by a regeneratively cooled cryogenic engine, which works on staged combustion cycle developing a thrust of 69.5 kN in vacuum.

The other stage systems include insulated propellant tanks, booster pumps, inter-stage structures, fill and drain systems, pressurisation systems, gas bottles, command block, igniters, pyro valves and cold gas orientation and stabilisation system.

Liquid oxygen (LOX) and liquid hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbo-pump, which rotates at 39,000 rpm to ensure a high flow rate of 16.5 kg/sec of propellants into the combustion chamber.

The main turbine is driven by the hot gas produced in a pre-burner. Thrust control and mixer ratio control are achieved by two independent regulators. LOX and gaseous hydrogen are ignited by pyrogen type igniters in the pre-burner as well as in the main and steering engines, ISRO explained.

“Apart from the complexities in the fabrication of stage tanks, structures, engine and its sub-systems and control components, CUS employs special materials like aluminium, titanium, nickel and their alloys, bi-metallic materials and polyimides", it said.