From: spike66 (spike66@attbi.com)
Date: Sun Jul 14 2002 - 19:44:54 MDT
Robert J. Bradbury wrote:
>I tend to disagree with spike in that I don't think small
>people will buy you that much...
>
I hear people say this a lot, and I always disagree. We would buy
ourselves a lot by choosing small people. The reason is not that the
people themselves have a low mass, but rather that they have a low
height. If we can scale down the mission by a factor of two in every
linear dimension, we drop a factor of 8 in the mass, because the mass
of a pressure vessel scales as the cube of the linear dimension. I know
this isn't obvious, but the surface area of a sphere scales as the square
of the radius and the thickness of the walls scales linearly, all else being
equal. Engineers, figure it out.
In fact, the space program has already used this. In the early days,
they were severely limited by mass. When NASA chose Mercury
astronauts, they could have used daredevils, prisoners, scientists,
athletes or citizen volunteers, etc. But they chose military fighter
pilots.
The reason had little to do with courage or ability to fly a spacecraft,
since there was not much to do in a Merc, thus the term "spam in a can."
They chose military pilots because they were already preselected at 5 foot
9 inches or less (175 cm) by the dimensions of a fighter plane cockpit
and the necessity of fighter pilots to pull high G loads. Just having them
short allowed the Mercury capsule to be made small.
Now imagine a lunar module and a number of astronaut candidates
who are a maximum of 88 cm tall. Could you not scale *everything*
down by a factor of 2? A half-scale LEM would have one-eighth the
mass. This could be launched for 1/8 the cost. Such a deal! We
should be able to find some really tiny women who want to go into
space.
...And we certainly aren't
going to have the ability to engineer them anytime soon.
Robert
We wouldn't need to. Nature has produced them already. We just
need to find them and select them. I estimate that this planet has a
couple dozen candidates less than 88 cm, who would be willing,
able and eager to take a risky shot at becoming the mother of a new
race of exo-terrestrials. spike
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