 Hi aspirants, if you want to truly understand about the history of development of cryogenic engines in India You must know a little bit about missile technology control regime, which is shortly known as MTCR See MTCR seeks to limit the proliferation of missiles and missile technologies Currently India is a member of MTCR, but this was not the case in early 1990s So in 1991 an agreement was signed between India and Russia for technology transfer to India So based on this agreement, the Russian developed cryogenic engine KVD-1 can also be built indigenously in India But in 1993 the US imposed sanctions on ISRO saying that the agreement between ISR-1 Russia violated MTCR So this forced India to develop cryogenic technology indigenously So in this short video we will learn about what is cryogenic technology Do you guys remember about the little science experiment that we used to do in our school days? When we mix sulphuric acid with a metal like zinc or iron, a gas is released And when you bring a burning match or a candle near the gas, you can hear a loud pop sound The gas that is emitted in this reaction is hydrogen and the pop sound that you hear is because hydrogen is combustible And this combustible property of hydrogen is used in the cryogenic engine See the cryogenic engine uses the liquid hydrogen as propellant and liquid oxygen as oxidizer Know that oxygen liquefies at 183 degree centigrade while hydrogen exists in liquid form below 253 degree centigrade Since these engines deal with various operations at such low temperatures, they are called cryogenic engines This is because cryogenic is the science of extremely low temperatures Although the operation of the engine is very complex, let me explain to you a highly simplified version of the working Look at this schematic diagram in the blue tank liquid hydrogen is stored and in the cyan tank liquid oxygen is stored And these two mix in the combustion chamber where combustion takes place In the combustion chamber hydrogen reacts Explosively with oxygen to produce water vapor and energy and this hydrogen oxygen reaction generates tremendous heat Causing the water vapor to expand and exit the engine nozzles at the speed of 10,000 miles per hour So this fast-moving steam creates the thrust that propels the rocket from earth according to Newton's third law One of the biggest advantages of the cryogenic engine is it is eco-friendly This is because as we saw the exhaust from the cryogenic engine is mainly water vapor So this is all about working of cryogenic engines and its associated technology Now let's see some points about C20 cryogenic engine of ISRO C20 is an indigenously developed cryogenic engine The C20 cryogenic engine is the one that powers the launch vehicle Mk3 We shortly call this as LMV3. The LMV3 has three stages There is the solid first stage, a liquid second stage and a cryogenic third stage So the C20 cryogenic engine is used in the upper stage of LMV MK3 This engine also uses liquid hydrogen as fuel and liquid oxygen as oxidizer I hope now you could understand what is cryogenic technology See these types of science and technology topics are very important for your preliminary exam To learn more topics like this, watch Hindu News analysis of Shankar IS Academy regularly Thank you for listening