The
hype for the "perfect site" for a first moonbase at
the Moon's south pole (Mt. Malapert) and more recently for a rival north polar
site, continues to get good press, and to all appearances, just about everyone
is on the bandwagon. I have serious reservations, however, and have found that
there are others who share them, but find it difficult or unpromising to buck
the trend.
A
north polar site has the great advantage of being less than half as far away
from the nearside maria
complex as the South pole. The North pole lies just
600 miles north of the North coast of Mare Frigoris, whereas the South pole is 1300 some
miles south of the southern coasts of Mare Humorum, Nubium, and Nectaris.
Industrially,
the highland/mare coasts have much to offer with the availability of both major
suites of regolith; highland regolith
enriched in aluminum and calcium, mare regolith
enriched in iron and titanium.
The
nearside mare complex embraces all the nearside maria except Crisium in one
interlinked area of relatively easy to traverse terrain and represents 39% of
nearside. Add to that, highland areas handy to the coasts.
The
problem with the polar sites is that they are ghettos. These places of
"eternal sunlight" are surrounded by very inhospitable terrain. We
will be on very uneven, even mountainous terrain with very confining and
limited flat areas. The shadows will be extremely long and dark and the shadow
pattern will be constantly changing, making visual cues as to one's whereabouts
or heading all but meaningless.
The
whole idea of going to the poles, is not to tap ice
(that's just "frosting on the cake") but to escape two requirements of settling
in anywhere else:
- Having to
store up power during the two-week long dayspan
in order to power equipment and systems during the two-week long nightspan
- Being
able to avoid the problems inherent in incessant bimonthly cycling between
extreme hot and extreme cold.
If
we tackle those problems head on from the start, then we own the whole Moon. If
we do not, then we only own tiny turflets at one or
both poles while the rest of the Moon remains off limits.
On
point [1] - "eternal sunlight"
I
believe that the "eternal sunlight" is available not at one precise
point, but at a string or chain of spots around a high point rim or massif at either pole. If
that is the case, it may take a significantly greater mass of equipment shipped
to the Moon's pole (either) in order to set up a power system that will have
solar input most (but still not 100%) of the time, than it would be to set up a
system elsewhere that would store up excess dayspan
solar input for nightspan draw.
Further,
we will still need such a power storage system at either pole, for those
periods, however minimized, that the sun doesn't shine.
To
me, the search for the eternal light brings with it the inherent drawbacks of:
putting us in very small local areas surrounded by much more challenging polar
terrain, putting us where we have no, or greatly reduced, access to iron and
other industrially essential elements more abundant in mare regolith.
Both poles are highland areas.
putting
us in a place from which it is hard to travel overland to anywhere else still
needing to have a power storage system on top of a more massive system of solar
arrays linked by cable around the polar mountain or rim crest having to set up
shop in relatively non-flat areas. Laying out the extended solar power array
system in mountain terrain, involves high risk to personnel and equipment.
This
euphoric "eternal light bandwagon" gripping perhaps most lunar enthusiasts and
supporters seems all very much like the momentary delight and anticipation of the moth that sees a bright porch light or
street light, and is drawn instinctively, unsuspectingly, to its certain doom.
Yes, we need water. But we need more iron and other materials. So is it better
to ship X tons of water to sites away from the poles, or 10X (to grab a figure)
tons of other materials to the poles?
The answer to that question seems to me to be a "no-brainer".
But
if you are someone who doesn't put much stock in the potential for lunar
industrialization, and who is only attracted to the polar ice reserves because
in addition to a supply of drinking water, they can be turned into rocket fuel
to support exploration, not of the Moon, but of the rest of the solar system,
then the polar sites offer just what you need. That you bring the Mountain (larger
tonnage of mare/highland regolith needed) to Mohammed
(ice) or bring Mohammed to the Mountain, is not a consideration. But consider:
did we build Los Angeles next to Prudhoe Bay?
You
don't feel trapped at the poles, because the whole idea is to establish a token
presence on the Moon, maybe with a token telescope to boot, and to leverage
that for fueling other solar system endeavors - You dismiss prospects of lunar
industrialization and settlement.
Now
David Schrunk and his team have indeed developed a
very ambitious scheme to use peak of eternal light sunshine to power a lunar
railroad network which will eventually extend over much of the Moon. A lot of
work has gone into that proposal in his Book: The Moon :
Resources, Future Development and Colonization, and I deeply respect that, and
highly recommend the book(*).
The
poles will be part of the lunar future. I just think that they should play a
supporting role, not the lead.
We
need to get our feet wet on the Moon in a way that will allow us to roam free
on the Moon, virtually every-where, not writing off the 99.999% of the Moon
which is not "eternally sunlit."
It
is not that difficult to design a system that traps excess dayspan
solar inputs for nightspan draws -- there are several
workable options and all ought to be pursued (let the technology pick the
winners!) And/or (I prefer and ) we can rely on a
nuclear power plant (as backup -- who ever heard of a nuke that never went down?)
So let's pursue this harder path, because it is a path that leads to
everywhere, not just to a tiny polar cul de sac.
If
we bring earth-moving equipment to the Moon that heats the soil and extracts
the trapped solar wind gasses in the process -- whether we are building roads,
grading sites, or gathering material for lunar processing, or to be transformed
into agricultural soils for those plants that do better in geoponics than in
hydroponics -- then we will have all the hydrogen we need for drinking, agriculture
and other biosphere needs, and for industrial processes in which the hydrogen
is recycled.
If
we don't want to develop such equipment or bring it to the Moon, then why
bother going? The Moon is an uphill battle. If we don't "What is worth doing,
it is worth doing right."
Finally,
point [2] avoiding temperature swings
If
we properly shield our habitat structures, either covering them directly with regolith or regolith-filled
sacks, or placing them under regolith shielded
hangers (an option that makes both maintenance and expansion easier), then the
temperature cycles will not affect them. These modules will be at constant
temperatures (the seasonal swing on the Moon being less than 3 degrees
(Fahrenheit, I believe) a couple of meters below the surface.
The
problem, rather, will be for those exposed structures, equipment, and vehicles.
We need to build them to withstand the heat of high lunar noon (all the Apollo
missions were conducted in "mid-morning" conditions.) as well as the intense
cold of the lunar night.
Look,
if we are not going to trap ourselves forever in very tightly confined polar
sunshine ghettos, we had better learn how to handle the thermal cycles right
away. If we postpone doing so, that postponement may well last decades, if not
forever. We have what happened after the departure of Apollo 17 from the Moon
in support of that grim prospect. Let's not pull our lunar punch!
We
need to build things out of materials with a minimum of thermal expansion -
reserving high thermal expansion materials for sheltered usage only.
We
need to develop seals that can handle the temperature swings. We need to
develop lubricants that can handle this thermal cycling or finding ways of
shading lubricated areas from direct sunlight and heating them when need be.
Silicone-based lubricants (oils and greases) are much better than
hydrocarbon-based ones in this respect. Super-magnetic bearings may be part of
the solution.
Argument
Summary
We
should/will go to the poles, eventually, to tap water ice, and use permashade to site telescopes that need cryo-thermal
conditions. The North Pole is more conveniently situated to the maria than the south pole -
[Galileo photo N Polar area] http://www2.jpl.nasa.gov/galileo/images/north.html
For
water-ice access, considered separately, permashade
deposits are likely to exist up to 400 miles south of the North Pole, or north
of the South Pole, for shortened access to the nearest mare coasts. This means
perhaps 200 miles or so from the North coast of Mare Frigoris
to the nearest likely north polar ice field, and 900 miles or so from the South
coast of Mare Nubium to the nearest plausible south
polar ice field. "Go north, young man!"
The
government is likely to build only one lunar outpost. To put it in a place from which we are equipped to go nowhere else, puts us
in a self-chosen ghetto. Those to gain most from such a site selection, at
either pole, are those who have their eyes set on refining hydrogen for use as
cryogenic rocket fuel for off-lunar transportation, those who are skeptical
about, and uninterested in, the development of the Moon's resources in a way
that will lead to substantial real settlement. At best, we will end up with
something akin to a North Sea Oil Rig Platform or an Antarctic science outpost.
The "escape path" that Schrunk et al. have outlined,
while brilliant, is, I fear, unlikely to be followed. We need to tackle the
lunar problems of power storage and thermal cycling head on if we really want
the keys to the Moon at large, not just the key to a "lunar closet."
So
NASA does what it wants to do anyway
So
what if the path (and fate) of moths is pursued anyway? In the long run, the
Moon will be developed by business and industry, not by the government. They
will find a way to do it right, because nothing else makes sense. However, the
establishment of a government moonbase at the poles
will be unhelpful. The equipment and systems developed by NASA for a polar site
will be specialized for conditions that exist nowhere else (except, possibly at
the other pole!). Thus the R&D burden facing commercial and industrial
users will remain untackled. So such a misguided
polar siting of a NASA base will defer, rather than
hasten, commercial development on the Moon.
What
is easiest is not always best. The right way is usually the hardest one. If we
have the right stuff we will pick that road. If we do not, we will deserve the
dead-end future of the moth fascinated by the light.
Reference:
The Moon : Resources, Future Development and
Colonization by David Schrunk, Burton Sharpe, Bonnie Cooper, and Madhu Thangavelu..
John
Wiley & Sons; (October 22, 1999) ISBN: 0471976350 Hardcover. 432 pgs
Peter Kokh is president of the Lunar Reclamation Society (NSS-Milwaukee)
which he helped found in 1986, and since August 2004, President of the Moon
Society. But his opinions above are stated only in his capacity as editor of
Moon Miners' Manifesto (www.moonminersmanifesto.com) a newsletter now in its
19th year of continuous monthly publication.