Cryogenic Rocket Engine Meaning of Cryogenics In physics

Cryogenic Rocket Engine

Meaning of Cryogenics In physics, cryogenics is the study of the production of very low temperature(below − 150 °C, − 238 °F or 123 K) and the behavior of materials at those temperatures.

Cryogenic technology o Cryogenic technology involves the use of rocket propellants at extremely low temperatures. o The combination of liquid oxygen and liquid hydrogen offers the highest energy efficiency for rocket engines that need to produce large amounts of thrust. o Oxygen remains a liquid only at temperatures below minus 183 ° Celsius and hydrogen at below minus 253 ° Celsius.

History of Cryogenic Technology Ø The United States was the first country to develop cryogenic rocket engines. with RL-10 engines, registered its first successful flight in 1963 still used on and is the Atlas V rocket. Ø Then The Japanese LE-5 engine flew in 1977 , French HM-7 in 1979 , Chinese YF-73 in 1984. Ø The Soviet Union, first country to put a satellite and later a human in space, successfully launched a rocket with a cryogenic engine only in 1987.

The first operational cryogenic engine

Cont……. (Russian) - N 1 (AMERICAN) - ATLAS V

Cont…. Ø To India the U. S. , Japan and France would either not provide the technology or do so only at an exorbitant price. Ø The 11 D 56 cryogenic engine had been developed for one of the upper stages of the mammoth N 1 rocket, the Soviet equivalent of Saturn V. But after four successive launch failures, the N 1 project was scrapped and its engines were mothballed. Ø The deal violated the Missile Technology Control Regime, which was intended to prevent the spread of missile-related technology, and fell foul of the U. S. laws meant to enforce its provisions. Despite warnings from within the organization, ISRO opted to go ahead with the import. In May 1992, the U. S. imposed sanctions on ISRO and Glavkosmos. A year later, Russia, which received the contract after the break-up of the Soviet Union, backed out of the deal.

Cont…. Ø ISRO then had no option but to develop the technology on its own. Ø At the time, ISRO gave the impression that much of the technology had already been acquired and further development would be quick. Ø A GSLV with an indigenous cryogenic engine would be ready to fly in about four years, Chairman U. R. Rao told in July 1993. Instead, it has taken 16 years.

Working Ø It involves a complicated ‘staged combustion cycle' to increase the engine efficiency. Ø Hydrogen is partially burnt with a little oxygen in a gas generator. The hot gases drive a turbo-pump and are then injected at high pressure into the thrust chamber where the rest of oxygen is introduced and full combustion takes place. Ø Before going to the gas generator, the incredibly chilly liquid hydrogen is used to cool the thrust chamber where temperatures rise to over 3, 0000 ° Celsius when the engine is fired.

Production & Manufacturing Ø The Indian cryogenic engine is produced by Godrej and the Hyderabad -based MTAR Technologies working together as a consortium. Ø Instead of ISRO first mastering the technology and transferring it to industry, the two companies were involved from the start and even the early prototypes were built by them.

Why didn't the cryogenic engine of India ignite? The GSLV D 3, which lifted off well from Sriharikota on Thursday, April 15, 2010 later plunged into the sea as the indigenous cryogenic engine failed to ignite. The vehicle lifted off as planned at 4. 27 p. m. and its performance was normal up to the end of its second stage till 293 seconds from the liftoff. An authoritative former ISRO official said: “It is very clear that the cryogenic engine did not ignite when you look at the curve [of the vehicle's trajectory] the vehicle developed problems when the cryogenic upper stage should have ignited 304 seconds after the lift-off, and it fell into the sea

Advantages High Energy per unit mass: Propellants like oxygen and hydrogen in liquid form give very high amounts of energy per unit mass due to which the amount of fuel to be carried aboard the rockets decreases. Clean Fuels Hydrogen and oxygen are extremely clean fuels. When they combine, they give out only water. This water is thrown out of the nozzle in form of very hot vapour. Thus the rocket is nothing but a high burning steam engine Economical Use of oxygen and hydrogen as fuels is very economical, as liquid oxygen costs less than gasoline.

Drawbacks: Boil off Rate Highly reactive gases Leakage Hydrogen Embrittlement Zero Gravity conditions

The next generation of the Rocket Engines All rocket engines burn their fuel to generate thrust. If any other engine can generate enough thrust, that can also be used as a rocket engine There a lot of plans for new engines that the NASA scientists are still working with. One of them is the “ Xenon ion Engine”. This engine accelerate ions or atomic particles to extremely high speeds to create thrust more efficiently. NASA's Deep Space-1 spacecraft will be the first to use ion engines for propulsion. There are some alternative solutions like Nuclear thermal rocket engines, Solar thermal rockets, the electric rocket etc. We are looking forward that in the near future there will be some good technology to take us into space

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