MMM Classics Year 10: MMM #s 91-100 - Moon Society

cosmic rays, splashout from other impacts). To date, the only
(and it’s inconclusive) teasing evidence we have is an
anomalous reading over western Mare Crisium that on first
interpretation would seem to indicate subsurface water-ice.
This reading has been (but should not be) routinely dismissed
as spurious.
> What lavatube uses are near term, what uses are more
challenging and likely to be realized only in the far future?
Warehousing and storage; industrial parks; settlement as
opposed to outpost; archiving. All of these can benefit from the
use of lavatubes much as we find them, without wholesale
modification. The idea of pressurizing tubes for more “terraform”
settlement presents a number of enormous hurdles
(sealing methods, sealant composition, pressurization stress,
importation from Earth of astronomical volumes of nitrogen,
etc.) and while in toto vastly easier than wholesale terraforming
of a whole surface (e.g. Mars) is still something we will not
tackle for some generations perhaps.
> How much total ready to go protected volume are we
talking about? For political purposes internal to the prospace
movement, let’s express our back-of-envelope
guesstimate range of the total available volume of intact lunar
lavatubes in terms of O’Neill Island III Sunflower space
settlement units. That’s ready-to-occuppy-and-use-NOW (for
those without 1-G and 24-hour sunshine hangups - they can
wait the generations it will take to build Sunflower units from
scratch !)
The surface area of the host terrain, the lunar maria,
comprise some 17% of lunar surface = 2.5 million square miles
- compare with 3 million square miles for continental U.S.
Now if (we have to start the argument somewhere!) we assume
that available floor and wall terrace surface of intact lavatubes
compares to 1/1000th the taking 1/1000th of this aggregate
lunar maria surface area, we get 2,500 square miles. This is in
our estimate, a very conservative fraction. Counting supposed
lavatubes in lower level lava sheets, 1/100th is a fraction that
could be closer to reality. That would yield 25,000 square
miles, an area comparable to West Virginia.
Subtracting for window strips (as we have for
lavatube upper walls and ceilings), an O’Neill cylinder, if ever
realized in full ambitious scale, might have 100 square miles of
habitable inner surface. Argue about the figures, it won’t
change the overall picture. We are talking about ready to
occupy network of lunar lavatubes that compares to 25 to 250
Island III units. If you are going to hold your breath until these
free space oases are built, I can only hope your life expectancy
is much more Methuselahn than mine {P. Kokh].
> Can we expect to find other similar hidden covered
valleys elsewhere in solar system? Yes, as they seem to be a
standard concomitant of lava sheet flooding and of shield
volcano formation, we might expect to find lavatubes on Mars,
Mercury (the temperature swing refuge would make them hot
property), Venus (they would be too hot, and share Venus’
over-pressurization), Io (protection from Jupiter’s radiation
belts), and even on little Vesta..
> By what Latin class name are such features likely to be
referred? (e.g. rima = rille) Cava, tubus, and ductus are
available Latin words. The latter better indicates the mode of
formation.
Teleo-Spelunking on the Moon
[Reprint of MMM #44, April ‘91, page 6]
EARTH-BASED SEARCHES FOR LUNAR LAVATUBES
Writing in Starseed, the newsletter of Oregon L5
Society, Oregon Moonbase researcher Thomas L. Billings
discusses ways to search out lunar lavatubes. Tube openings
are hard to spot by camera unless you are right on top of them
[but see note below]. While intelligent lunar base siting will
require better orbital mapping than provided for the Apollo
landings, the best method may be to look “through” the rock.
The severe dryness of the lunar surface should make this
possible for orbiting radar. (Airborne radar has been used
successfully to find lava tubes on the big island of Hawaii.)
To provide deep radar imaging, the antenna diameter
must be four times the radar wavelength being used. To
penetrate deeply enough we’d need a wavelength of 5-20
meters, meaning an antenna 20-80 meters across! That’s a lot
of mass to put into orbit along with the ancillary equipment.
Billings suggests a way out. Readings from a number
of smaller antennas in an interferometer array can substitute,
synthesizing an image. It will be tricky to do this in orbit, and
an intercontinental Interferometric is an option Using a 7 meter
wavelength, you’d have a 250 meter resolution and a penetration
of 70 meters, good enough to detect a convincing sample,
given that many tubes are likely to be larger than this.
However, a considerable amount of power will be
needed if the signal returning to Earth is to be detectable.
Computer algorithms needed to sift signal from noise are
getting better. Nor need the search extend beyond a few
months, so maybe the expense wouldn’t be out of line with the
rewards. TB
Editor’s Questions. & Suggestions:
1. Would it be practical to intercept that signal in lunar orbit
where it would be stronger?
2. Would Earth-based searches be limited to central nearside?
3. We could use the same instrumentation package to search
for tubes on Mars, Mercury, Venus, Io, and Vesta, worlds
with shield volcanoes and lava sheets.]
Using Orbiting Infrared Cameras
to Find Collaborating Evidence
According To Bryce Walden and Cheryl Lynn York
of Oregon Moonbase, orbiting side-looking infrared detectors
may on occasion peer into the entrance of a fortuitously
oriented lavatube, detecting its characteristic subsurface
temperature, clearly distinct from ambient surface readings, in
sunshine or out. Illustration in previous article.
Moon Miners’ Manifesto Classics - Year 10 - Republished January 2006 - Page 91