India’s indigenous cryogenic engine
India’s indigenous cryogenic engine
India’s space agency, ISRO, crossed another milestone on Thursday afternoon, launching its first 2000-kg-plus satellite on a launch vehicle powered by an indigenous engine.
GSLV, or Geosynchronous Satellite Launch Vehicle, is an advanced launch vehicle that can be used to carry satellites heavier than 2000-kg, even those weighing up to 5000-kg, into space.
GSLV’s higher capabilities, as compared to the PSLV or Polar Satellite Launch Vehicle that has made 28 successful launches in a row, is made possible by a the cryogenic part of the three-stage engine.
In January last year that the first GSLV with an indigenous cryogenic-stage engine made a successful flight.
Cryogenics is the science of producing and studying low-temperature conditions. A low-temperature environment is termed a cryogenic environment when the temperature range is below the point at which permanent gases begin to liquefy. Permanent gases are elements that normally exist in the gaseous state and were once believed impossible to liquefy. Among others, they include oxygen, nitrogen, hydrogen, and helium.
Cryogenic conditions are produced by one of four basic techniques: heat conduction, evaporative cooling, cooling by rapid expansion (the Joule-Thomson effect), and adiabatic demagnetization.
- Electrical resistance of metals. Electrical resistance is the tendency of a substance to prevent the flow of an electrical current through it. Scientists had long known that electrical resistance tends to decrease with decreasing temperature. They assumed that resistance would completely disappear at absolute zero.
- The discovery of superconductivity led other scientists to study a variety of material properties at cryogenic temperatures. Today, physicists, chemists, material scientists, and biologists study the properties of metals, as well as the properties of insulators, semiconductors, plastics, composites, and living tissue. Over the years, this research has resulted in the identification of a number of useful properties. One such property common to most materials that are subjected to extremely low temperatures is brittleness. The recycling industry takes advantage of this by immersing recyclables in liquid nitrogen, after which they are easily pulverized and separated for reprocessing.
- Next cryogenic material property that is sometimes useful is that of thermal contraction. Materials shrink when cooled. To a point (about the temperature of liquid nitrogen), the colder a material gets the more it shrinks. An example is the use of liquid nitrogen in the assembly of some automobile engines.
- Another space application of cryogenics is the use of liquid helium to cool orbiting infrared telescopes. Infrared telescopes detect objects in space not from the light they give off but from the infrared radiation (heat) they emit. However, the operation of the telescope itself also gives off heat, to prevent the instrument from being blinded by its own heat to the infrared radiation from stars, parts of the telescope are cooled with liquid helium. At the temperature of liquid helium (1.8 K) the telescope can easily pick up infrared radiation of the stars, whose temperature is about 3 K.
A cryogenic rocket engine is a rocket engine that uses a cryogenic fuel or oxidizer, that is, its fuel or oxidizer (or both) are gases liquefied and stored at very low temperatures.
Various cryogenic fuel-oxidizer combinations have been tried, but the combination of liquid hydrogen (LH2) fuel and the liquid oxygen (LOX) oxidizer is one of the most widely used. Both components are easily and cheaply available, and when burned have one of the highest enthalpy releases by combustion, producing specific impulse up to 450 s (effective exhaust velocity 4.4 km/s).
High thrust cryogenic engine
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 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.
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.