Re: Moon landing anniversary

From: fudley (
Date: Thu Jul 22 2004 - 10:49:36 MDT

Wed, 21 Jul 2004 "Dani Eder" <> said:

> It has solar cells that are 35% efficient, and ion
> thrusters to maintain it's position that are 10x
> as efficient as chemical rockets.

But a communication satellite just needs a tiny amount of thrust for
station keeping, to get from low Earth orbit to the moon you would a
vastly larger velocity change and thus more thrust if you wanted to get
there before the Astronauts died of old age or radiation exposure.

> So, today we are talking $500M or so to return to
> the Moon, rather than the $100B it cost for Apollo.

I think that estimate is many orders of magnitude too low, and ion
engines won’t help you much in blasting off from the moon, assuming you
want to get them back.

John K Clark

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