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Icy-Conclusion-3500 t1_j246l34 wrote

Reply to comment by Nibb31 in Lunar Gateway for Dummies? by Significant_Youth_73

To obtain moon-sourced fuel.

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Nibb31 t1_j25gqz3 wrote

SpaceX operations, including NASA HLS, rely on orbital refueling from Starship tankers.

Once that is up and running, there isn't much advantage in producing rocket fuel on the Moon.

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404_Gordon_Not_Found t1_j24qr12 wrote

Which is more expensive, risky and complex than just sourcing from Earth

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Background_Daikon992 t1_j257tzc wrote

Only if you've invented a space elevator.

It takes 8 pounds of rocket fuel to get 1 pound of payload into LEO. Cutting gravity by 5/6ths has the potential for exponentially smaller fuel costs.

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404_Gordon_Not_Found t1_j25bko4 wrote

That's entirely ignoring the cost and difficulty of setting up, running and maintaining a large industry on the moon. Even your base premise is wrong, the most expensive part of a rocket isn't the fuel, it's the rocket itself, that's why reusable rockets are the trend now.

Let's illustrate how unnecessary it is to refuel on the moon, then go to another place like for example, Mars.

It takes similar amount of fuel to go to Mars compared to the moon. What you are suggesting is that instead of launching and refueling from Earth, then head to Mars, we should:

  1. Launch all the machines and equipments needed for a mining and refinery facility on the moon.

  2. Assemble, run and maintain said facility with materials from Earth, because the moon doesn't have all resources needed to be self sustaining.

  3. Launch a rocket all the way to the moon, land, refuel and take off again towards destination, in this case Mars.

There's all disadvantages and no advantage to what you suggested, it's like taking a massive detour to build a new gas station in the middle of nowhere just so you can continue on a trip, instead of going to the gas station nearest to you. I simply cannot see the value in setting up moon as a gas station of space, not with current and near future technology.

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Background_Daikon992 t1_j25k9k9 wrote

Those "reusable rockets" have to be so large and complex because they contain ridiculous amounts of fuel.

It takes "a similar amount of fuel" getting to the moon as getting to Mars because in both cases, you burn the overwhelming majority of your fuel just getting out of Earth's gravity well.

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