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Shmav t1_ixed63y wrote

Reply to comment by Wagyuwithketchup in Realistically speaking When do you think we will land humans on Mars? by EnaGrimm

You realize the majority of fuel rockets use is just to break earth's gravity, right? Having a spaceship gas station on the moon seems like a pretty big win to me.

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wgp3 t1_ixejxvn wrote

You're exactly right which is why you're exactly wrong too. The majority of fuel is used getting into earth orbit. Once in earth orbit it takes basically the same amount of delta v to land on the moon as it does on Mars. This is due to the atmosphere of Mars being capable of slowing you down whereas no atmosphere on the moon. So a fuel stop on the moon is quite useless for going to mars.

As for a fuel stop in orbit around the moon then it becomes more likely. However, it would be easier to have one in earth orbit rather than lunar orbit. So it would be a long time before any fuel depot would be needed around the moon. Definitely not needed for any initial Mars missions.

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Shmav t1_ixesn6y wrote

Taking off from the moon would still require less fuel than taking off from Earth. That would allow the spacecraft to have a lot more fuel to get to Mars and maneuver once there.

Also, they could launch a craft from the moon to refuel the craft headed for Mars, further reducing their fuel consumption. There are a few ways to skin that cat and make the trip to Mars easier and safer. In space travel, easier and safer seems like a pretty good idea to me.

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wgp3 t1_ixf12xs wrote

Taking off from the moon to go to mars would take less fuel but ignores the fact that we have to take off from earth first. You either take off from earth and go to mars, or you take off from earth go to the moon and then mars. To skip taking off on earth requires us to build out mining, manufacturing, and ship launching stations on the moon. All monumentally more difficult than just fueling up in earth orbit.

The trip to mars is not safer or easier by building out manufacturing and mining on the moon and then doing cryogenic transfer in deep space. Much safer to use earth resources and cryo transfer in earth orbit where if something goes wrong it can more easily be rectified.

There's a few ways to skin a cat but that doesnt mean they're all equal for the current tech level.

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