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Dave K and I are both right although the casual reader may not see it.
He's right under the assumption that all your mass is going to come from earth
and you need a place to assemble all the bits and pieces into a ship that was
too big to launch in one place. For that use, some orbit somewhere is ideal
since you will pay less delta-V to get to a Hohman transfer orbit.
I'm right under the assumption that you should get as much as your mass from a
place that has a much lower escape velocity than Earth (and no pesky atmosphere)
but which has a lot of resources to derive that mass from.
In the best moonbase plan, all the structural members of your ship are lunar
aluminum, all the soil used in the habitat module is lunar rock, crushed, with
some microbes you brought with you added, all the oxidizer is lunar oxygen, all
the solar panels on the ship are made from lunar silicon, etc etc etc.
At least IMHO.
As to whether to use a hohman transfer or a constant boost, I prefer constant
boost if you can afford the reaction mass. It's faster except for really small
thrust values. But for chemical, you need monstrous amounts of reaction mass
since Isp is so low, which argues for ion drive for orbital operations. Only use
chemical for leaving the moon (if you didn't build a catapult, but you should!)
and the final landing operation
XFUT .debate again.
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Message is in Reply To:
 | | Re: We're here to go
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| (...) If I recall correctly, 90 percent of the fuel of any launch from the earth is used to get thru the atmosphere--that it's only 10 percent that is used for combatting gravity. That said, lifting off the earth, then landing on the moon, then (...) (20 years ago, 16-Jan-04, to lugnet.off-topic.geek)
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