The Moon as a Puzzle

Behind Door #1


The Moon Seems to be a barren, useless “rubble pile” with which it is difficult to imagine that we could do anything useful.

But let’s take a second looK!

Behind door #1 The “location” and “outline” of the first “door” to the hidden potential of the Moon was hinted at in the Apollo moondust and moon rock samplings and their analysis. An abundance of oxygen, silicon, and calcium, plus an abundance of the three major “engineering metals”: iron, aluminum, magnesium, titanium. We’ve but to look through the door’s peephole.

The key to open this door lies in homework we can do on Earth. We need to know how to isolate or “produce” these elements out of the mineral complexes in which they are combined, more inconveniently than we’d like. Except for iron, a considerable amount of which is available unoxidized, in pure metal fines, in the “pre-mined” upper regolith, a “blanket of dust” pre-pulverized by eons of micrometeorite bombardment. We need only a magnet to harvest this resource. But otherwise, largely because the Moon did not undergo tectonic processing of its crust in the presence of water (hydrotectonic processing), it has no ore veins of concentrated metals in simple mineral combinations.

The Moon’s mineral wealth is not to be gotten so easily. But it is there.

We need to do processing experiments, using simulant soils superior to those we have toyed with to date. They must resemble moondust not just in the percentages of the elements represented, but in the chemical mineral combinations to be found on the Moon, as well. We have no, or little, experience extracting elements from such minerals.

Yes, we have done some work on figuring out how to extract oxygen. But to paraphrase a well known proverb, “settlers do not live by oxygen alone.”

Nor is it enough to do “lab” experiments. Techniques suitable on so small a scale are often unsuitable for scaling up to “production-batches”. “Chemical Engineers” need to be involved — the guys who can design factory-scale chemical processing.

Nor are the raw engineering metals enough. We need to develop ways to extract and isolate many elements present in lesser abundances as alloy ingredients, color pigments, as ingredients for glass, glass composites, ceramics, cement and manufacturing stuffs and building products in general. The dance card of the chemical engineers is quite full.

How can we do this homework without federal funds? We brainstorm profitable terrestrial applications of the techniques and processes we are developing for the lunar frontier. That way we make money now and at the same time put “on the shelf” the technologies we need once we get there, paid for out of the profits of terrestrial applications, not taxes. This is the “spin-up” route.

Many still look to the rocket scientists to deliver the Promised Land. But as much as we need them to figure out how to realize “cheap access to space”, it is the chemical engineers who will be able to tell us how to access space resources. (And without the agricultural and biosphere engineers and the human factors engineers, there won’t be any “we” out there to do any thing with these resources.

If you in search of a career that will put you at the forefront of opening the space frontier, one of the options just listed may be for you. Space is a place. Transportation just gets us there. After we arrive, we need to have opened these “doors” if we aren’t just going to sit there “stranded”.

Behind Door #2

Behind Door #2: The location of this “door” lay in two clues: the Moon’s axis is nearly perpendicular to the plane of the Earth-Moon system’s orbit around the Sun. So the Moon has no seasons. As the Moon is not a perfectly smooth sphere, there must be places near both poles, in craters at least (crevasses are not a lunar feature), in which “the Sun never shines.” These “permashade areas” are stable “cold traps”, very frigid places where volatile elements (relatively high boiling points, with the vapor or gas easily dispersed by the incessant solar wind) might have accumulated over millions and billions of years.

NASA planned a Moon Observer, equipped to answer the question of whether or not any cometary volatiles, dispersed in nighttime impacts with the Moon, might have reached the polar cold traps before the Sun arose over the horizon to disperse them. But this probe was a “phantom mission”. The craft was to be the “backup Mars Observer”. Congress, as superficial as most everyone else, convinced that there was nothing useful to learn from further Moon missions, and in an effort to rein in Mars Observer program costs, canceled the backup craft. Almost end of story!

Scientists and space activists knew the “ice question” was important, deserving an answer. To our collective credit, Lunar Prospector was born and designed outside NASA. LP was available as a Discovery Mission project when the opportunity finally arose. The rest is history. Lunar Prospector’s instruments found several times as much hydrogen at the poles in permashade polar cold traps as exists elsewhere (per unit area). Unlike the hydrogen to be found globally, embedded in surface soils by Solar Wind buffeting over billions of years, the polar hydrogen signal data are best explained as coming from water ice, rather than excess concentrations of Solar Wind protons. The Moon, it seems, “behind Door #2”, has major reserves of water ice at both poles.

As an elegant afterthought, as the “Little probe that Could” wound down its extended mission at low altitude, it was aimed “blind” towards a crash landing into a polar crater expected to contain layers of water ice. The hope was that the impact would throw clouds of dust and telltale water vapor, high up enough above the rim of the Moon to be detected by Earth-based instruments as well as by Hubble.

It didn’t happen. But to look at the media headlines, “Lunar Prospector fails to find water”, some of these headlines echoed in pro-space publications (for shame!), you would think that all the data LP had gathered in the past eighteen months was somehow now suspect!

Balderdash. Even if the selected crater does have a bottom-filling ice layer, several things could have prevented a splashout:

1) the craft, impacting at low angle, did not penetrate all the way through a surface layer of dust expected to cover the ice layer.

2) the craft may have haplessly impacted the side of a large boulder or rock outcrop that was ice-free (seems reasonable enough!)

3) the water vapor may have reacted with the soil as it accumulated, producing cement cakes rather than ice.

We need to have a ground truth probe to find out. But perhaps the Powers That Be are happy not to have a “positive finding” lest they be derailed from their preoccupation with Mars. (We need to explore and settle both worlds!)

Those who want to access what lies “Behind Door # 2” need to put together a segue discovery mission, this time to land at one of the poles and do a ground truth search and a quantitative and qualitative assay of whatever reserves it finds. Lunar Polar Lander, like the “lunar polar probe” later renamed Lunar Prospector, will almost certainly be up to us. The most we can expect is that NASA will pay the costs as a Discovery Mission opportunity if we can keep those costs down to a bare minimum, and if the craft is as capably instrumented as it needs to be to get the job done.

Water is essential for life support, agriculture and the biosphere in general as well as closed-loop industrial uses. It is NOT essential for rocket fuel. Liquid hydrogen IS invaluable for getting us out of the deep throat of Earth’s gravity well. We can do well enough with less potent substitutes once we are in orbit and beyond. To burn up an unreplaceable resource to get our rockets off – all in a one-time non-recyclable impatient exercise makes no sense. If this polar hydrogen resource is in the form of cement hydrates instead of free water ice, it will be harder to access. That may prove a blessing as it will work to discourage the pillagers more than the settlements.

Behind Door #3

Behind Door #3: Lunar Prospector mapped the lunar globe by tracking a number of elements. One of these was the radioactive element thorium. There are apparently appreciable reserves of this element in various areas of the Moon. Thorium is transmuted into fissionable Uranium 233 in a fast breeder reactor. Thus the Moon apparently has the wherewithal for a major nuclear fuels industry.

Thorium and Uranium 233 are nuclear fission fuels. They produce energy by the splitting of heavy atoms. The atomic bomb and all current nuclear plants operate on the fission principle. But the hydrogen bomb and nuclear plants built to operate on the same principle, produce energy by combining lightweight atoms (hydrogen, deuterium, tritium, helium-3). Now it turns out that the same solar wind which has put a considerable amount of hydrogen protons into the lunar topsoil or regolith, has also endowed that layer with a wealth of Helium-3, the ideal fuel for fusion reactors, if we can overcome the engineering hurdles in making such plants a reality. Helium-3 could be the long term cure for Earth’s stubborn energy and environmental problems.

As to the fissionable Th232 => U233 resource, this too may be an invaluable export. Fringe environmentalists could conceivably succeed in banning the transport of all nuclear fuels through Earth’s atmospheric. While chemical rockets can support Mars exploratory expeditions of trained and dedicated crews, that real settlement, migration to Mars is most unlikely unless we have fleets of nuclear ships able to make the trip in much less time and over extended launch windows. Two plus two = .. . You guessed it! In that not improbable scenario, Lunar Thorium could fuel the opening of the Mars Frontier.

Behind Door #4

Behind Door #4: It would seem that the entire surface of the Moon is exposed to the wind and waves of cosmic weather. Micrometeorites rain down incessantly everywhere. The intense raw solar ultraviolet washes everything. There is no shelter anywhere from the fury of Solar Flares and cosmic rays. The Moon’s surface is an unending, unbroken desolation that is as deadly as it is magnificent.

The first hint that this was not the whole story came with the Apollo 15 landing mission alongside Hadley Rille, a winding “sinuous” valley. Upon examination, the valley did not seem to be “carved out” by either water or lava. Instead it is the relic of a subsurface lavatube, what is left of it after the roof collapsed on top of its floor, creating the trench above. From orbit, we’ve looked at similar “sinuous rilles” elsewhere on the Moon. They are a feature to be found only in the congealed lava flow “seas” called maria, usually near the “coasts” where the highlands begin or end. And lava sheets, formed by runny lava (like the kind that forms shield volcanoes) are just the sort of environment in which lavatubes form. Indeed, lavatubes are the principal means by which these sheets advance over the terrain they end up burying.

It would seem that to protect ourselves, we must build outposts on this storm-washed surface, then pile up a healthy layer of moondust on top, to serve as a solid protective blanket in the same way as Earth’s atmosphere provides a gaseous blanket to offer us the same protections.

Have all lunar lavatubes collapsed? Do they only exist as relics? as natural ruins? Apparently not. Some such rille valleys are discontinuous. They consist of a number of sections separated by “interruptions” of apparently normal looking flat surface continuous with the surrounding host terrain. These natural bridges can only be interpreted as surfaces hiding intact lavatube sections. And where we have partially intact lavatubes it is reasonable to expect we will find some that are both wholly intact and not flood-filled by subsequent flows. Other evidence comes from rows of “collapse pits”, rimless craters that are a sure sign of caverns below.

The maria may be ridden with these tubes, and not just in the surface layer. As the mare [MAH ray] sheets built up layer by layer, tubes would have formed in each, some to be later flooded, some not. And wherever the surface-ceiling cover exceeded 40 meters or so, cave ins and overall collapses will have been unlikely except in case of a direct hit by a sizable asteroid tidbit.

These lavatubes, of immensely larger scale than those we find on Earth, thanks to appreciably lower lunar gravity, and, immensely more ancient (billions rather than thousands of years old), provide hidden but real anchorage, safe harbors not only from the cosmic elements and solar weather, but also from the extremes of surface dayspan heat and nightspan cold — and from the mischievous moondust that is otherwise everywhere.

We need to map these subsurface features, something that has yet to be attempted. Tom Billings of the Oregon L5 Society has brainstormed a two-part sleeve/core “radar flashbulb” probe design. Aimed at promising sites, the probe would be aimed to impact the surface, forcing the outer sleeve to telescope over the inner core and thus generate an electromagnetic signal at just the right frequency to illuminate any “voids” within say 8 kilometers of the impact area. The signals reflecting off the hidden voids will be readable by either a wide-array of radar telescopes on Earth, or a dedicated space radar array in near-Moon space.

Designing the probe and proving the concept is one thing. Picking the right targets is another. The plan is to use special computer software to pour over the voluminous Clementine high sun angle photographic data, looking for telltale shadows of “skylight” and “terminal” entrances to tubes. This search will take both time (possibly 18 months of run time) and money.

A successful mission or series of missions, possibly flown as Discovery opportunities, will forever change how people look at the Moon. It will be suddenly more than a monotonous rock pile. It will become, in the public awareness, a real world with real safe harbors and protected hidden valleys.

There are other hidden doorways to the Moon of “unsuspected world-potential”, and it has been MMM’s guiding mission to uncover the possibilities one by one. Next time you hear someone say “The Moon? Been there, done that!” you will know that you at least are able now to see behind the rock pile face to the “real Moon inside” — a rock that can become a world, if we only open all the right doors.

Time is ticking

Meanwhile, the Moon Society is endeavoring to encourage those national space agencies planning future lunar orbiter, lander, impactor missions to include the instruments needed to close this knowledge gap in our tentative map of the Moon’s Economic Geography. This map includes the concentrations of several key elements, but at low resolution: iron, thorium, potassium/phosphorus (KREEP), and now, thanks to SMART-1, calcium. We need better concentration maps at higher resolution of all major elements present in economically recoverable percentages in the lunar regolith.

We need higher horizontal and vertical resolution topographic data, form which to plan logical transportation corridors.

We need penetrating radar to map the subsurface voids like lavatubes and gas pockets.

Encouraging these prospecting and exploration priorities is an ongoing long-term effort.

Peter Kokh