Moon Base baby steps

Air launch does have advantages, mostly for thinner air (neither the speed
nor the altitude per se is very significant), but it also limits your rocket's
mass to what your aircraft can carry, and even for a 747 that's fairly
limited.
Overall, a 25% fuel/weight advantage has been calculated for an air-launched
rocket. A quite significant advantage!


^
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~~~ near space elevator ~~~~
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On Sun, 25 Jan 2004 22:07:16 GMT, (Henry Spencer)
wrote:

Hadley Rille, which Apollo 15 landed beside, is almost certainly a
collapsed lava tube.

Any photos around of that?

(Lunar lava tubes can be *big*.) A few halfway-
intact ones have been spotted in images taken by orbiters. Some of them
show up as "dashed lines" -- the roof has fallen in on some parts but not
other parts, which might be very convenient for getting into them.

Ok, so what would you do with a cavern sized lava tube? As this
surface does not seem so strong if you pressurize one. After all you
said yourself that these have been subject to collapse, even if some
may go deeper.

There is also the problem that the walls of this cavern could suck the
moisture out of your air. So it seems to me that you will have to add
artificial walls in order to solve all these problems.

A lava tube through solid rock would be much more desirable.

Worth looking into though, where a ground penetrating radar is a must
have of any orbital mission.

Cardman
http://www.cardman.com
http://www.cardman.co.uk

Cardman wrote in message . ..
On Sun, 25 Jan 2004 22:07:16 GMT, (Henry Spencer)
wrote:

Hadley Rille, which Apollo 15 landed beside, is almost certainly a
collapsed lava tube.

Any photos around of that?

(Lunar lava tubes can be *big*.) A few halfway-
intact ones have been spotted in images taken by orbiters. Some of them
show up as "dashed lines" -- the roof has fallen in on some parts but not
other parts, which might be very convenient for getting into them.

Ok, so what would you do with a cavern sized lava tube? As this
surface does not seem so strong if you pressurize one. After all you
said yourself that these have been subject to collapse, even if some
may go deeper.

You put free standing Transhab-derived inflatable living space inside
without having to worry about piling regolith on top. Shielding for
free, and far more effective than a few feet of regolith. Room to
grow, too.



There is also the problem that the walls of this cavern could suck the
moisture out of your air. So it seems to me that you will have to add
artificial walls in order to solve all these problems.

for a moonbase far in the future, sure. Short term, it's just for
shielding.


A lava tube through solid rock would be much more desirable.

Worth looking into though, where a ground penetrating radar is a must
have of any orbital mission.
Cardman

true enough.

Tom Merkle

Joe Strout wrote in message ...
In article ,
(Ross A. Finlayson) wrote:

I guess my idea of a moonbase is a bunch of domes, using the
"regolith" as structural material.

Cylinders are more likely than domes, at least as a first step. And the
regolith is shielding material, not structural material.

Inflatable domes or tubes aren't particularly stuctural, either.
There's no water, so concrete is out of the question, but maybe melted
regolith could serve as structural elements. You could use an
inflatable dome as the armature to form a hardened surface of melted
regolith over. Is there a good way to melt a little bit of regolith at
a time? I'm thinking maybe inflate a dome or tube, have a little
rover push up 20 or 30 cm of lunar dust up against it as heat
sheilding, have another little rover with a melting chamber (lasers?)
melt a pile of lunar dust outside that. Push some more lunar dust,
melt a little more, and gradually build up a ceramic surface over the
dome, that could support a couple of meters of regolith. It would
take a year or two, but you could end up with a habitable structure
anywhere you wanted it.
Harmon

In article ,
Cardman wrote:
Hadley Rille, which Apollo 15 landed beside, is almost certainly a
collapsed lava tube.

Any photos around of that?

Lots, I'm sure, but I don't have any URLs handy.

Ok, so what would you do with a cavern sized lava tube? As this
surface does not seem so strong if you pressurize one.

At least for starters, you wouldn't pressurize the whole tube. But it
would provide a shelter, giving a stable thermal environment and screening
out radiation and micrometeorites.

After all you
said yourself that these have been subject to collapse...

A segment that's stood up for a few billion years of impacts is likely to
continue doing so (although you'd certainly want to study it first).

There is also the problem that the walls of this cavern could suck the
moisture out of your air. So it seems to me that you will have to add
artificial walls in order to solve all these problems.

If you did pressurize the whole tube, almost certainly you would first
coat the walls with a sealant of some kind.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

On 26 Jan 2004 05:45:25 -0800, (Harmon
Everett) wrote:

Joe Strout wrote in message ...
In article ,
(Ross A. Finlayson) wrote:

I guess my idea of a moonbase is a bunch of domes, using the
"regolith" as structural material.

Cylinders are more likely than domes, at least as a first step. And the
regolith is shielding material, not structural material.

Inflatable domes or tubes aren't particularly stuctural, either.

They can made to be I guess, with added supports. Not of course to
forget that the internal air pressure would make for some very solid
walls.

And if you want your easy-up moon base, then that is an idea.
Air-lock, windows and just some pipes and tubing in order to get
things in and out like electricity.

Making them expandable would also be an idea.

That would save NASA wasting billions on their ISS on the moon, where
my only concern would be the extreme cold of no sunlight, or the high
heat of direct sunlight.

There's no water, so concrete is out of the question, but maybe melted
regolith could serve as structural elements.

If you tried melting it, then I could only envision lots of impurities
making your job of making a solid wall very difficult.

You could use an inflatable dome as the armature to form a hardened
surface of melted regolith over.

If you had your inflatable dome, then I do not believe that you should
try making your own regolith sand castles out of it.

Is there a good way to melt a little bit of regolith at
a time?

Focused sunlight.

I'm thinking maybe inflate a dome or tube, have a little
rover push up 20 or 30 cm of lunar dust up against it as heat
sheilding, have another little rover with a melting chamber (lasers?)
melt a pile of lunar dust outside that. Push some more lunar dust,
melt a little more, and gradually build up a ceramic surface over the
dome, that could support a couple of meters of regolith. It would
take a year or two, but you could end up with a habitable structure
anywhere you wanted it.

And what about windows and getting things like electricity and people
in and out?

Cardman
http://www.cardman.com
http://www.cardman.co.uk

(Henry Spencer) wrote:

In article ,
Cardman wrote:
Hadley Rille, which Apollo 15 landed beside, is almost certainly a
collapsed lava tube.

Any photos around of that?

Lots, I'm sure, but I don't have any URLs handy.

Use Google's image search, such as:
http://images.google.com/images?sour...ille+Apollo+15

(Henry Spencer) wrote in message ...
If you did pressurize the whole tube, almost certainly you would first
coat the walls with a sealant of some kind.

I think you'd just use an inflatable pressure vessel which is larger
than the diameter of the lava tube. Then inflate, until the pressure
vessel is constrained by the tube walls. That's your sealant. The main
requirement where it's in contact is abrasion resistance, rather than
tensile strength. That's good, because abrasion resistant structures
can be made on the moon, whereas tensile structures are high tech
single piece products which for some time would need to be made on
Earth.

(Henry Spencer) wrote in message ...

If you did pressurize the whole tube, almost certainly you would first
coat the walls with a sealant of some kind.

A sealant and pressure vessel.

I wouldn't want to depend on brittle rock holding in 4 or 14.7psi.
While the weight of rock overhead might be enough to contain that,
you're still introducing new, large tensile and hoop stresses to
brittle material.

A purpose-built cave...sure. I think some stored power systems use
caves pressurized to 20 atmospheres. But a natural rock formation? You
first.

Mike Miller, MatE

"Ross A. Finlayson" wrote in message om...

[Lunar mass drivers]

I think one of the key advancements required is the high-termperature
superconductor.

Or you could just launch stuff at night. Any superconductors around
that work at -140°C? Who says the extreme nocturnal cold has to be
your enemy in *every* respect?


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