#95 May 1996
Section 22.214.171.124.095.of the Artemis Data Book
[Continuing to a New MMM Series]
The primitive roots of "Lunan" Culture, II
Last month we talked about the brute physical realities that will begin shaping Lunan culture from the day of our return and the establishment of the first overnighting beachhead outpost - fractional gravity, naked exposure to the cosmic elements, and the natural quarantine between outposts.
This month we continue the story with those brute physical facts that will insert themselves, if not on day one, then shortly thereafter to begin carving nascent Lunan culture even more deeply. - The Moon is a very dry world. And its mineral assets lack several of the industrially strategic elements Earth's more generous endowment has lulled us into taking for granted. MMM
by Peter Kokh
MMM #95 - May 1996
Relevant Readings from Back Issues of MMM
MMM # 23 MAR '89, pp 4-5 "Gas Scavenging" MMM # 44 APR '91, pp 5-6 "Ice Caves" MMM # 51 DEC '91, p 5 "Ice Found on Mercury!" MMM # 67 JUL '93, pp 3-8 "Water & Hydrogen: lunar industrial grease"; "Hydro Luna"; "Reservoirs"; "Settlement Water Company"; "Xeroprocessing" MMM # 78 SEP '94, p. 3 "Why hotter Mercury may have polar ice while the colder Moon may have little."
Compared to the Moon, Tatooine, of Star Wars I fame, would be a paradise oasis world. Away from the lunar poles, you can encircle the Moon, a 6,800 mile trek, without finding water. The closest thing to even the false comfort of a mirage will be Earth's blue oceans hanging tauntingly overhead in the black Nearside skies, some 238,000 miles away.
At the poles the story may be different. Volatiles such as water and carbon oxide molecules released on impact from rare cometary bombardment during local nightspan may have found their way to the safety of polar permashade coldtraps before local dawn, there to freeze out on the floors of craters whose interiors never see the rays of the Sun. The jury is still out on this, though indirect readings from Clementine over the lunar south polar region have been very teasing. Most sober estimates have been that the various loss mechanisms likely to be in effect (erosion from the solar wind, cosmic ray bombardment, micrometeorite rain) are likely to swamp the assumed rate of accumulation. That is, any ice deposits would be ephemeral and erode away or sublimate over time.
There is no one making such an estimate who would not be delighted to be proven wrong. Hopefully, we will not have long to wait. Lunar Prospector, next in line in NASA's Discovery Mission series, is due for launch next summer, equipped with precisely the right instruments to give us a definitive answer to the question. Any ice deposits Lunar Prospector might miss are probably too skimpy or thin to be of near term economic value.
The positive finding of substantial ice fields at the poles of Mercury, a world much closer to the Sun, has encour-aged many. But Mercury's accumulation mechanisms may be significantly stronger. We simply have to wait and keep our fingers crossed, determined, should the results from Lunar Prospector prove negative, to make the best of "Plan B".
"Plan B" is to scavenge the hydrogen nuclei or protons adsorbed to the fine particles of the upper meter or so of the regolith, thanks to the incessant buffeting of the lunar surface by the Solar Wind over the past 4 billion years plus. Hydrogen is present in this surface layer on the order of 1 ton of hydrogen per 10,000 of rock powder (regolith) along with lesser amounts of other volatiles: carbon, nitrogen, helium, neon and other noble gasses. 10,000 tons of regolith is the equi-valent of the material removed from an excavation 3 meters deep by 30 meters wide and 40 meters long. Equipping all our 'lith-moving equipment to heat the material handled in order to extract these gases for later separation would be a prudent and provident strategy. We have called this process "primage".
Just how much water does this hydrogen source represent? One ton of hydrogen with 8 tons of oxygen (super abundant) yields 9 tons of water. If we could extract all the Moon's hydrogen to produce water, we could in theory cover all the lunar maria to a depth of say a centimeter or 3/8ths of an inch (and guess how fast that would soak in!!) Or we could make a crater lake 60 miles across and 30 ft. deep. Gathered all together it seems like a lot, but for the whole Moon? It's really very very little. No desert on Earth is as parched as the Moon. The Gobi, the Sahara, the Kalahari, the Takla Maklan - they are all dripping wet in comparison.
Even if Lunar Prospector confirms substantial water ice reserves at either or both poles, tapping them will not be easy. The ice temperature is likely to be extremely cold, the ice very hard and resistant to harvesting machinery which will be prone to break down all too frequently.
And should engineers come up with a simple smooth running system to extract this frozen wealth, how fast can we harvest it and put the water to work? In comparison to the rate at which these conjectured ice fields were laid down, any rate of extraction will completely swamp the rate of replacement. In other words, for all practical purposes, like oil on Earth, lunar polar ice is not a renewable resource. It behaves us to use it wisely. The number one demand will be for cryogenic rocket fuel. Make that number one in obscenity as well. We'd do best to use other lunar-sourceable fuels and save the water for recyclable uses in industry, agriculture, and biosphere support.
Will reason prevail? The temptations of impatience are always the strongest. A sustainable human culture on the Moon will have to be built on alternatives. Water-ice at the poles or no, Lunan culture will be characterized with an attention to water conservation beyond anything we have experienced on Earth, even in drought-stricken regions. Water is the blood of the biosphere. It is not free.
To what extremes will water conservation be carried? We have already spoken of the need to rethink airlocks to conserve nitrogen. The same will be true of water vapor. Conduits or pipelines and tankers carrying water or hydrogen in other forms (methane or ammonia, for example) will have to be designed for instant leak detection and ready repair. Materials of any kind with a hydrogen content (carbon or nitrogen too, for that matter) will need to be religiously recycled and reserved for intensive usage purposes.
Will Lunans carry things as far as the Fremen in the great Frank Herbert science fiction epic "Dune"? The desert-living Fremen wore "stillsuits that recycled their perspiration and urine into drinking water. Lunans may try.
We are used to life on a water-rich world with oceans, lakes, rivers, underground aquifers, and dependable rainfall. On the Moon there is none of this. Think for the moment of the ratio of plant matter to human matter. There is much more total mass of the former. Then think of the ratio of water to plant biomass. Again there is much more of the former. Will we be able to reproduce such healthy ratios within mini lunar biospheres? Both ratios on the Moon are likely to much smaller, not too much above safety margins and dependent on high efficiency short-cycle turnarounds. That could be a prescription for disaster as it leaves little room for error or accident or other unplanned misadventure.
Reserves will have to be built up through frugality in usage. At the same time, every opportunity to add to those reserves from external sources must be taken within the limits of affordability.
We talk of a lunar settlement becoming self-sufficient. Ability to self-manufacture a large portion of its needs for domestic consumption is one thing. Ability to survive an interruption of lifeline supplies from Earth is something else. The umbilical cord can only be replaced with a yolk sac, that is with ample reserves of all vital supplies. Foremost among those are water, nitrogen, and carbon - scarce on the Moon, polar reserves or no.
Unlike us Earthlings, Lunans will hardly take air and water for granted. Culture and the language itself will be transfigured by a high degree of attention to the conservation and renewal of these resources. Those who in the early days may have mined lunar polar ice for rocket fuel will go down in Lunan history books as trashing plunderers, no matter what their other accomplishments. Transportation is not everything nor the only thing and there are alternatives. Other lunar-sourceable fuel combinations and the rocket engines to burn them need front burner development, not continued consign-ment to paper studies on library shelves.
Because of this high danger of misuse, and of further postponement of development of alternatives, positive findings by Lunar Prospector should be greeted with concern by the thoughtful. But amidst all the excitement, who will want to listen to words of caution? There may never be a Lunan culture if we do not. MMM
Contents of this issue of Moon Miners' Manifesto