Rocket engines space launch vehicles

In rocket science, helium is used to boost liquid hydrogen and liquid oxygen out of the tanks into the engines during the take off It is also applied to purge liquid hydrogen systems in space launch vehicles. 

Integrated high performance turbine engine technology Integrated high payoff rocket propulsion technology NASA reusable and expendable launch vehicles In-space propulsion... 

Spacecraft engineering is the process of designing, constructing, and testing vehicles for deployment and operation in the full expanse of space above the Earth s atmosphere, generally regarded as beginning at an altitude of fifty miles. Launch vehicles and rocket propulsion are considered part of the related but separate field of rocketry. 

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