For liquid oxygen, Spacex is building an air separation plant at its facility in Texas to grab it from the air.
For methane, didn't know this but looked it up, methane is one of the cheapest propellants, but rocket grade methane needs to be purer (starship is estimated to cost $300k to $1 million to refuel)
For methane, didn't know this but looked it up, methane is one of the cheapest propellants, but rocket grade methane needs to be purer (starship is estimated to cost $300k to $1 million to refuel)