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TNPSC Current Affairs February 2017: ISRO Successfully Tests Cryogenic Upper Stage Engine for GSLV Mark III Rocket

ISRO successfully tests its indigenously developed "Cryogenic Upper Stage engine for GSLV Mark III Rocket"

ISRO's Cryogenic Upper Stage Engine for GSLV Mark III 

Indian Space Research Organisation (ISRO) has successfully ground tested its indigenously developed Cryogenic Upper Stage engine for GSLV Mark III at its Liquid Propulsion Complex at Mahendragiri in Tirunelveli district of Tamil Nadu on 17.02.2017. ISRO Chairman AS Kiran Kumar said the full duration flight test of cryogenic upper stage for GSLV Mark III was successful. He said yesterday's test was last in the series before going for an actual rocket launch. The engine will be put into use in April. 

C25 Cryogenic Stage 

The C25 stage is the most powerful upper stage developed by ISRO and uses Liquid Oxygen and Liquid Hydrogen propellant combination. The development of C25 cryogenic stage will provide ISRO capability to launch four ton class satellites in Geosynchronous Transfer Orbit.

GSLV MARK 3

The Geosynchronous Satellite Launch Vehicle Mark III: also referred to as the Launch Vehicle Mark 3, LVM3 or GSLV-III)is a launch vehicle developed by the Indian Space Research Organisation (ISRO). It is intended to launch satellites into geostationary orbit and as a launcher for an Indian crew vehicle. The GSLV-III features an Indian cryogenic third stage and a higher payload capacity than the current GSLV.

Indigenous Cryogenic Engine and Stage

A Cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages. Specific impulse (a measure of the efficiency) achievable with cryogenic propellants (liquid Hydrogen and liquid Oxygen) is much higher compared to earth storable liquid and solid propellants, giving it a substantial payload advantage. 

However, cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to its use of propellants at extremely low temperatures and the associated thermal and structural problems. 

Oxygen liquifies at -183 deg C and Hydrogen at -253 deg C. The propellants, at these low temperatures are to be pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of cryo fluids and related safety aspects. 

ISRO's Cryogenic Upper Stage Project (CUSP) envisaged the design and development of the indigenous Cryogenic Upper Stage to replace the stage procured from Russia and used in GSLV flights. The main engine and two smaller steering engines of CUS together develop a nominal thrust of 73.55 kN in vacuum. During the flight, CUS fires for a nominal duration of 720 seconds.

Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbopump to ensure a high flow rate of propellants into the combustion chamber. Thrust control and mixture ratio control are achieved by two independent regulators. Two gimballed steering engines provide for control of the stage during its thrusting phase.

Definition of 'Cryogenic Engine'

Definition: A cryogenic engine/ cryogenic stage is the last stage of space launch vehicles which makes use of Cryogenics. Cryogenics is the study of the production and behaviour of materials at extremely low temperatures (below -150 degree Centigrade) to lift and place the heavier objects in space. 

Description: Cryogenic stage is technically a much more complexed system with respect to solid or liquid propellant (stored on earth) stages due to the usage of propellants at extremely low temperatures. A cryogenic engine provides more force with each kilogram of cryogenic propellant it uses compared to other propellants, such as solid and liquid propellant rocket engines and is more efficient. 

Cryogenic engine makes use of Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) as propellants which liquefy at -183 deg C and -253 deg C respectively. LOX and LH2 are stored in their respective tanks. From there they are pumped in to turbo pump by individual booster pumps to ensure a high flow rate of propellants inside the combustion/thrust chamber. The major components of a cryogenic rocket engine are combustion/thrust chamber, igniter, fuel injector, fuel cryo pumps, oxidizer cryo pumps, gas turbine, cryo valves, regulators, the fuel tanks and a rocket engine nozzle.

Sources: Wikipedia, The Economic Times, www.isro.gov.in

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