danger of putting space station in the moon

(Wondering Joe) wrote in message . com...
The earth's atmosphere is our first line of defense from falling
asteroid. There is no atmosphere in the moon. If you telescope the
moon you'll see too many craters caused by asteroids falling in the
moon. Unlike the International Space Station it can evade the
asteroid. Space station in the moon they'll need to install missiles
to protect it from dropping asteroids.

The biggest risk to ISS is space junk, which sometimes it can avoid.
There is no risk of space junk on the moon.

The next risk is micro meteorites, which can puncture the ISS. A moon
base could (should - for radiation purposes) be protected by a layer
of regolith, which means it's a much harder base than the ISS.

I know a fellow who is interesting sometimes and frustrating, because
to him all risks seem same size: very, very large. I've thought of
advising him to stay indoors on sunny days, else he may get a terrible
fright from his shadow.

But the point is, if you're alive, you're at risk. As observed up
this thread, Luna's craters are an accumulation over a few millions of
years and the infall rate there seems not terribly dangerous now. And
knowing the risk means you can do something about it.

Concerning those risks, where is the most safe place on Luna?
Sub-Earth? (Earth directly overhead, remember Luna is orbitally
locked.) The leading side near the equator? The trailing side? More
near the poles? Etc etc, and don't forget, a fragment from a meteor
strike could orbit for several years and zip past at 5.5 feet just in
time to take you out if you're standing there.

I think base siting in a Lunar lava tube is an interesting idea,
however, seems to me anybody settling there is going to be doing a lot
of engineering and science on the surface.

Cheers -- Martha Adams

In article ,
Martha H Adams wrote:
Concerning [impact] risks, where is the most safe place on Luna?
Sub-Earth? (Earth directly overhead, remember Luna is orbitally
locked.) The leading side near the equator? The trailing side? More
near the poles? ...

Farside vs nearside vs leading or trailing edge really doesn't make very
much difference. Earth is too small and too far away to provide much
actual shielding, and the Moon's orbital velocity is too slow to be of
great importance.

The safest place is probably hunkered well down in a not-too-big polar
crater. A fair bit of the biggest incoming stuff has orbital velocity
*roughly* in the plane of the ecliptic, so it's coming in roughly at right
angles to the Moon's axis, and it'll be below the horizon in the bottom of
a modest-sized polar crater. (The bigger the crater, the shallower it is.)

Comet debris comes in from all angles... but as it happens, probably the
single biggest impact threat in the Earth-Moon system is comet debris from
a predictable direction: the Leonid meteor showers. When the Leonids
storm, you get roughly a year's worth of meteors in an hour or so... and
they're coming in at 72km/s instead of the usual average of around 20km/s.
(Leonid impacts on the Moon have been seen, as flashes on the night side.)

But the Leonids always come at the same time of year and from the same
direction in the sky, and if memory serves, by chance it's quite close to
the plane of the ecliptic. So in your polar crater, they too are below
the horizon.

However, the bottom of that polar crater may be a trifle chilly...
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

On Mon, 26 Jan 2004 18:08:38 GMT, (Henry Spencer)
wrote:

But the Leonids always come at the same time of year and from the same
direction in the sky, and if memory serves, by chance it's quite close to
the plane of the ecliptic. So in your polar crater, they too are below
the horizon.

Sounds like an idea, but not really needed if you are under the
regolith or in a lava tube.

However, the bottom of that polar crater may be a trifle chilly...

They could always add some Sun tracking mirrors to reflect some
sunlight.

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

(Henry Spencer) wrote in :

However, the bottom of that polar crater may be a trifle chilly...

Won't there be similar problems building in a lava tube? No sunlight there
either.

--
Coridon Henshaw - http://www3.telus.net/csbh - "I have sadly come to the
conclusion that the Bush administration will go to any lengths to deny
reality." -- Charley Reese

In article ,
Coridon Henshaw (chenshawREMOVE wrote:
However, the bottom of that polar crater may be a trifle chilly...

Won't there be similar problems building in a lava tube? No sunlight there
either.

Not nearly as bad, because it's not exposed to black sky. Underground
temperatures are reasonable -- a bit cold but not very -- and quite stable
(with the caveat that our data is on shallow depths in soil, not on
lava-tube interiors, and at only a couple of sites).
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

(Henry Spencer) wrote in message ...
In article ,
Coridon Henshaw (chenshawREMOVE wrote:
However, the bottom of that polar crater may be a trifle chilly...

Won't there be similar problems building in a lava tube? No sunlight there
either.

Not nearly as bad, because it's not exposed to black sky. Underground
temperatures are reasonable -- a bit cold but not very -- and quite stable
(with the caveat that our data is on shallow depths in soil, not on
lava-tube interiors, and at only a couple of sites).

Ambient temperature of -21 degrees seems optimum for working in a
space suit where there's limited heat loss via conduction.

Longer term, there may be a problem of getting rid of excess heat. I
think the chemical processing units and heavy industry would need to
be on the surface for this purpose.