iirc helium is used in spacex starship raptor engines
“iirc helium is used in spacex starship raptor engines”
Helium is an inert gas. It is used in the space industry (where I work) as a purging agent. Different cryogenic fuels are used in the space industry, so when a system needs purging, you use a gas that will not freeze nor provide flammable fuel to the system. The only thing helium would be used for on a rocket engine is to purge the system of dangerous gases (Liquid Hydrogen, Liquid Oxygen, Liquid Methane, etc...)
We use helium in testing and calibration.