From: Dani Eder (danielravennest@yahoo.com)
Date: Wed Jul 21 2004 - 09:31:12 MDT
--- Eliezer Yudkowsky <sentience@pobox.com> wrote:
> 35 years ago today, on July 20th 1969, humans walked
> on the Moon.
> Let's hope it wasn't our all-time high point.
Since I am a rocket scientist, I feel like commenting
on this anniversary. We went to the Moon when it was
just barely technically possible, and therefore cost
almost an infinite amount of money. As a consequence
of the Apollo program, NASA is institutionally set up
to run big, expensive programs. Thus we have the
space shuttle and space station (I work on the
latter),
which between them have eaten most of NASA's budget
over the past 30 years.
Meanwhile, technology has kept advancing. A couple
of days ago a six ton communications satellite was
launched: http://www.spacetoday.net/Summary/2469.
It has solar cells that are 35% efficient, and ion
thrusters to maintain it's position that are 10x as
efficient as chemical rockets.
Using a Delta IV rocket to Earth orbit, and ion
thrusters to travel to lunar orbit, you can get
about 2/3 the mass to that point as a Saturn V
could. With technology improvements in structural
materials and electronics, that would be enough
to get a functional equivalent to the lunar lander
to the surface of the Moon.
So, today we are talking $500M or so to return to
the Moon, rather than the $100B it cost for Apollo.
In 20 years, additional technology improvements
should bring the cost down to $20M or so, bringing
it in the range of rich folk's play money.
Daniel
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