Re:Starship / Super Heavy
by simonh on Sunday December 27, 2020 @03:11AM
(#25549637)
More than that actually, it takes I think 3 tankers to fully top up a Starship in orbit, and the Lunar model needs to go into an elliptical orbit towards the moon and have at least one more top up again before having enough fuel for the rest of the mission.
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Re:Starship / Super Heavy
by throwaway316943 on Sunday December 27, 2020 @08:03AM
(#25550727)
I thought the full refuel was only necessary for a Mars mission?
It’s interesting. Going to the moon, propulsive my landing, and propulsively taking off and returning to Earth takes more dV than just a boost to Mars. If you think about it boosting to Luna and Mars aren’t much different in dV, but then you have lunar landing and takeoff again to do. Even with a very thin atmosphere, you can still shed the vast majority of your interplanetary velocity with aero braking at Mars.
As a result the Lunar variant actually needs a lot more fuel delivered to it than the Mars version. Even one full refuel in LEO isn’t enough, and it needs to boost part way to an intermediate elliptical orbit and get another top up.