[extropy-chat] SPACE: Back to the Moon (?)

[Mike Lorrey]

--- JAY DUGGER <duggerj1 at charter.net> wrote:
> On Thu, 30 Oct 2003 14:28:06 -0800 (PST)
>   Mike Lorrey <mlorrey at yahoo.com> wrote:
> >
> >
> >Firstly, regolith is dirt/sand in consistency, not rock. 
> >You apply it
> >with something like a snowblower, and you get it off with 
> >the same plus
> >a broom. (Lunar Sanitation Engineers Guild Local 001 
> >Trainee Manual,
> >Care of Antique Lunar Modules for Idiots).
> >
> 
> I don't know much lunar geology. Won't regolith 
> composition vary greatly over the surface? I can see this 
> holding true some places. There it might be a little 
> sweeping to place and remove the stuff.

Regolith is the detritus of meteorite impacts over billions of years.
It is fairly pulverized stuff.

> 
> >Secondly, leaks occur in space modules due to 
> >micrometeorite impacts,
> >primarily, along with radiation induced metal fatigue, 
> >both of which
> >regolith will mitigate.
> >
> 
> Welds don't fail, I suppose? Metal never fatigues due to 
> mechanical stress, from launch or temperature variation? 
> Such failure might not happen very often, but help lies 
> far away.

Not really. A potable wire fed Mig welder is about the size of a small
beer cooler. Popped welds are a sign of structural weakness compared to
actual stresses of the application. Properly designed and built, there
should be no popped welds from one launch and a few days in transit to
the moon. Where you get fatigue is from objects in orbit/trajectory and
exposed to radiation  and heat/cold for a long while, i.e. a couple
years or more. Most space junk comes from upper stages abandoned in
orbit and they do not become hazards for years until their rotation
(i.e. alternating between heat and cold) and radiation exposure cause
failures.

If properly protected from radiation and thermal variation by regolith,
bonds between module components should become more secure with time.
Metals in a vacuum, especially when unoxidised, tend to sinter together
over time, i.e. weld themselves.

> 
> >Thirdly, since the pressure is on the inside and vacuum 
> >is on the
> >outside, the proper place to fix any leak is on the 
> >inside.
> >
> 
> I'd feel much safer with a patch on _both_ sides of a hole 
> and sealant between the two layers, but I have no 
> experience with repairing pressure chambers and so admit 
> ignorance.

A patch on the outside doesn't do anything. When you get a hole in your
cars tire, do you put a patch on the outside? No, you first put a plug
in the hole for a short term fix. For a long term fix you seal it with
a patch on the inside.

=====
Mike Lorrey
"Live Free or Die, Death is not the Worst of Evils."
                                                    - Gen. John Stark
Blog: Sado-Mikeyism: http://mikeysoft.zblogger.com
Flight sims: http://www.x-plane.org/users/greendragon/
Pro-tech freedom discussion:
http://groups.yahoo.com/group/exi-freedom

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