- Cryogenic technology involves the production and use of materials at very low temperatures, particularly used in rocket engines with propellants like liquid hydrogen and liquid oxygen. - USA (NASA/ ULA), European Space Agency (ESA - Arianespace), and Japan (JAXA) are major space powers that have successfully developed and utilized cryogenic rocket engines in their launch vehicles for decades. - India has indigenously developed its own cryogenic engine technology for its GSLV program, a significant achievement.