4 ms·
Methane is about 900-1500$ / ton. About 1000 tons is used for the launch in addition to 3600 tons of lox. That should be a bit cheaper than methane per ton. Ba
by jillesvangurp 2y ago
Methane is about 900-1500$ / ton. About 1000 tons is used for the launch in addition to 3600 tons of lox. That should be a bit cheaper than methane per ton. Ballpark, the propellant might cost around 2M$.
A modern airliner on a long flight might burn around 80 tons of kerosene. It's slightly cheaper than methane. Call it 75-80K$.
- bombcar 2y agoThat's $7 of fuel per pound of payload, that is not bad at all.
- pfdietz 2y agoIndeed. You sometime see an argument that launch to space is expensive because of the propellant and therefore energy required. And as you note this argument is utterly wrong.
- throwaway4aday 2y agonot sure how anyone can miss the "throwing away the airplane" part as being the cost driver.
- pfdietz 2y agoIt's the same cognitive error as thinking nuclear energy must be cheap because the fuel is cheap.
- TMWNN 2y ago>And as you note this argument is utterly wrong. Am I mistaken, or are there distance/payload combinations for which Starship is cheaper per pound on a point-to-point basis than air transport, even setting aside 30 minutes versus 12 hours? Isn't that the non-intuitive outcome of ballistic trajectories?
- adastra22 2y agoNo. But it gets within an order of magnitude, which is remarkable. Economy class on starship could be priced similar to first class tickets on transoceanic flights.
- zaroth 2y agoIs the $1000/ton a law a physics, or could that ever possibly scale up and come down an order of magnitude?
- pfdietz 2y agoThere are no dollars in the laws of physics. It's connected ultimately to productivity of all the activities involved, and there's no obvious upper bound to productivity.
- WalterBright 2y agoThere's the rocket equation. https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
- pfdietz 2y agoWhich doesn't have dollars anywhere in it.
- WalterBright 2y agoThe point of the rocket equation is there are hard physical limits on what rockets can do, and dollars won't change it.
- pfdietz 2y agoThat's nice. It doesn't imply a lower bound for costs, just of ratios of costs.
- jillesvangurp 2y agoJust the current market price for fossil methane, which of course goes up and down. But I'm assuming SpaceX gets their methane on the open market. It's quite possible that SpaceX has access to some cheaper methane source. Texas produces a lot of it. And SpaceX has speculated about eventually switching to some renewable source by e.g. synthesizing methane. In which case that would boil down to cost of electricity and carbon. I don't see that becoming cheaper short term but that could happen long term.
- deleted 2y ago[deleted]