Re: alternative to terraforming

From: Doug Jones (
Date: Tue Jun 06 2000 - 18:34:44 MDT

"Michael S. Lorrey" wrote:
> Anders Sandberg wrote:
> >
> >
> > Still, I think the hollowed out asteroid idea might be tricky to
> > implement due to the unknown quality of the rock. After all, most
> > asteroids have been subjected to meteoride bombardment, which suggests
> > that there may be cracks - definitely not something you want in your
> > walls in space.
> SImply landing and doing acoustic measurements and capacitance measurements
> should provide very good data on structural integrity. Pentrating radar should
> work well as well...

On the gripping hand, rock has lousy tensile strength. Try making a
beer keg sized 1-bar pressure vessel out of a good piece of granite-
fairly difficult, and you'll have to select your stone carefully. Now
try to make one house sized, without piling so much gravel on top that
the overburden provides more than a bar of pressure- and without
cracking the load bearing walls. You're gonna *live* in that thing?
Without a pressure suit? Scares me and I'm fearless.

Space habitats are inherently tension structures unless they are buried
beneath about 100 kPa worth of material- which on an asteroid could be
kilometers in depth.

For various gee fields, to get one bar with 2500 kg/m3 regolith

Body Gee Depth (m)
Mars .38 10
Luna .16 23
Ceres .05 73
Eros .001 3700

Bite the bullet and make steel and fiberglass out of the regolith.
Hollow rocks are merely caves.

Doug Jones
Rocket Plumber, XCOR Aerospace

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