spacex 168SpaceX believes a fully and rapidly reusable rocket is the pivotal breakthrough needed to substantially reduce the cost of space access. The majority of the launch cost comes from building the rocket, which historically has flown onlySpaceX, NASA, and the United States Armed Forces work closely together by means of governmental contracts. ... [168] Raptor is a new family of liquid oxygen and liquid methane-fueled full-flow staged combustion cycle engines to power