Why in the News?
- ISRO has achieved a breakthrough in developing a semi-cryogenic engine (liquid oxygen/kerosene engine) with a high thrust of 2,000 kN (kilonewtons).
- The first successful hot test of the Engine Power Head Test Article (PHTA) was conducted at the ISRO Propulsion Complex, Mahendragiri, Tamil Nadu.
- This engine will be used in the semi-cryogenic booster stage of the Launch Vehicle Mark-3 (LVM3), enhancing India's space launch capabilities.
About Geosynchronous Transfer Orbit (GTO)
What is a Transfer Orbit?
- A Transfer Orbit is used to move a satellite from one circular orbit to another in a fuel-efficient manner.
- The Hohmann Transfer Orbit is a commonly used maneuver for such transfers.
Geostationary Transfer Orbit (GTO)
- GTO is a highly elliptical orbit with:
- Perigee (closest point to Earth): 180-200 km above Earth’s surface.
- Apogee (farthest point from Earth): ~35,900 km (near geostationary orbit).
- Why is GTO Used?
- Satellites are first placed in GTO before they use their own propulsion system to move to a final geostationary orbit (GEO).
- This reduces the energy required from the launch vehicle, making it more fuel-efficient.
What is a Semi-Cryogenic Engine?
A semi-cryogenic engine is a type of liquid rocket engine that uses:
- Liquid Oxygen (LOX) as an oxidiser (cryogenic component).
- Refined kerosene (RP-1) as fuel (stored at ambient temperature).
Advantages over Cryogenic Engines:
|
Feature
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Cryogenic Engine (LOX + LH2)
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Semi-Cryogenic Engine (LOX + Kerosene)
|
|
Fuel used
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Liquid Hydrogen (LH2)
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Refined Kerosene (RP-1)
|
|
Density impulse
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Lower
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Higher (more efficient thrust)
|
|
Cost
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Expensive
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More Cost-Effective
|
|
Storage
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Requires Ultra-Cold Storage (-253°C)
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Kerosene stored at normal temperature
|
|
Handling
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Difficult
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Easier
|
Significance of ISRO’s Semi-Cryogenic Engine Development
- Engine power head test success: The hot test of the Power Head Test Article (PHTA) was conducted for 2.5 seconds to validate the ignition and boost strap mode operation.
- All engine parameters performed as expected.
- Developed by: Liquid Propulsion Systems Centre (LPSC) under ISRO.
- Upcoming plans: Further series of tests on PHTA before realizing the fully integrated engine.
- Replacement for Current LVM3 Core Stage:
- The SC120 stage (powered by SE2000 engine) will replace the existing L110 stage in LVM3.
- Payload capacity in Geosynchronous Transfer Orbit (GTO) to increase from 4 tonnes to 5 tonnes.
Key Differences: Cryogenic vs Semi-Cryogenic Engines
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Feature
|
Cryogenic Engine (LOX + LH2)
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Semi-Cryogenic Engine (LOX + Kerosene)
|
|
Oxidizer used
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Liquid Oxygen (LOX)
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Liquid Oxygen (LOX)
|
|
Fuel used
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Liquid Hydrogen (LH2)
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Refined Kerosene (RP-1)
|
|
Storage
|
Requires ultra-cold storage (-253°C)
|
Can be stored at normal temperature
|
|
Efficiency
|
Lower density impulse
|
Higher density impulse (more efficient thrust)
|
|
Cost
|
Expensive
|
More cost-effective
|
|
Handling
|
Difficult to store and handle
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Easier to store and handle
|
|
Used in
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Cryogenic Upper Stages of rockets
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Booster stages of heavy-lift launch vehicles
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