dumb question, but at what point does the cost of fuel start to become an issue with such frequent launches? today I imagine launch cost is dominated by the price of the nonrecoverable parts, but fuel will become the floor no?
Starship is more efficient than F9 but in terms of multiple launches per day, the supply chain is indeed a factor. An hourly launch cadence is going to consume roughly as much natural gas as Houston.
All back of envelope here just to get a rough order of magnitude:
Starship needs 10kg (0.5mcf) of methane and 36kg of oxygen per kg to orbit. The oxygen takes 22kWh to liquefy or about (0.16mcf to generate that onsite). So 0.66mcf/kg to orbit and 66,000mcf from to fully fuel.
That is the daily gas usage of a midisze city, say 200k population, per launch.
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)
Propellant for a Falcon 9 launch is ~$500K.
Starship needs 10kg (0.5mcf) of methane and 36kg of oxygen per kg to orbit. The oxygen takes 22kWh to liquefy or about (0.16mcf to generate that onsite). So 0.66mcf/kg to orbit and 66,000mcf from to fully fuel.
That is the daily gas usage of a midisze city, say 200k population, per launch.
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)