Spring is in full bloom here in the metroplex, so I had to dig the rollerblades out of the closet. This will be my fifteenth year rollerblading, and I think the main reason that I continue to do so is that it is absolute joy. There’s a small park here in Addison Circle with a nice loop over by the airport that I like to blade around, in part because it reminds me of the ‘roller rink’ in Central Park, NYC.
Back in the 90s, there was one area of the park, over by the angel fountain, IIRC, where a DJ would set up on the weekend with some amps, and rollerskaters and rollerbladers would circle around a paved oval jamming out to the music. Such a liberated, free-wheeling, unorthodox use of public areas was clearly contrary to the best corporate wishes of a Giuliani-led NYC, and the DJs were ordered out of the park. Undeterred, they set up a small broadcast antenna and took over one of the unused lower bands on the FM dial, and everyone would tune in and continue to groove in sychronicity around the rink. Well this really upset the authorities, who may have even gotten their FCC buddies involved, and the broadcasts stopped. So then people were left to their own individual walkmans, the rhythm was lost, and a beautiful thing died.
So I memorialize it in a way with my MP3 player and the Addison Loop, swooping around like an airplane taking off or landing from the adjacent Addison Airport, sometimes with the waxing gibbous Moon rising in the east to the tune of ELO’s “Ticket to the Moon”. Once you get some speed up it is almost like flying.
Screen capture from
‘Planetes’ Ep.7: “Extraterrestrial Girl”
Which brings us to the Moon, where we should be able to fly in reality, with a large enough space and the right equipment. It will probably take a while to get to that point, but there have been many other forms of exercise proposed for the Moon in the interim. In his classic work “Where the Winds Sleep”, Neil Ruzic imagines a future history that describes the establishment of a Moonbase from 1975 to 2045. In 2025 we get the astrodomes. He opens the chapter:
“On the Moon you can make ten miles an hour on foot, a hundred fifty on a bicycle.”
Now that would be some wipeout, even in the low gravity of the Moon! Tricycles might be a bit more useful for stable transport and having more tire on the ground for traction. I can easily see maintenance workers using them to reach outlying areas of a base, such as a nuclear reactor.
Considering other sports, the author explores baseball and how the rules would be changed (and why), football, and soccer. We find out that just because the gravity on the Moon is only 1/6th that of Earth, that doesn’t mean that everything gets multiplied by six as a result. Especially things like long jumps that need a running start.
Because running on the Moon is hard to get started. Even walking on the Moon is hard, and is more akin to loping or kangaroo-hopping than regular striding. Anyone who has been to Space Camp gets to go for a Moon walk in the 1/6th Gravity Chair, which is something akin to a bicycle saddle that goes between your legs, and then they hoist it up by tightening springs until you only weigh 1/6th of your Earth weight. Then you get to try to walk, which can be a hysterically funny exercise, and jump,which is a lot of fun. A Zero-G flight can also provide several Lunar gravity parabolas to get a brief taste of the delight of 1/6th gee.
Once you do get up to speed, changing direction is really hard, since you’re not getting the traction you would get here on Earth. Rollerbladers will probably have a relatively easier time of it, but this will certainly add new complexities to many of the games we play for exercise. Just imagine tennis! Formal running tracks are likely to be inclined to assist in the turns around the course, cycling tracks even more so.
In the book “A la Decouverte de la Lune”, a very nicely done Moon travel guide that has not yet been translated into English, the authors note that on Earth if you jump straight up with both of your legs together the best you’ll usually do here is 45 cm, while on the Moon that would be over 3 m! Timewise you would spend about 0.7 seconds in the air here on Earth, 3.5 seconds airborne on the Moon. The rules for gymnastics are going to have to be entirely re-written for the Moon!
Getting into extreme gymnastics, the book “Growing up Weightless” by John Ford features a “Spider Room” where the kids create challenges for each other involving extremely dextrous moves in mazes and trellises and other fiendish constructs. Sort of a less-lethal variant of the well-known ‘Danger Room’ of Marvel Comic’s X-Men.
In “Where the Winds Sleep”, there’s a brief explanation of why a high jumper that could clear a six foot bar here on Earth would not therefore clear a thirty-six foot bar on the Moon. It’s all in the physics - when a high jumper clears a six-foot bar he has only raised his all-important center-of-gravity (CoG) about three feet up. On the Moon this would translate to just over eighteen feet (3 x 6), plus the original three-ish from the ground to the center of gravity gives a twenty-one foot clearance.
Center-of-gravity is also important for rollerblading. Knowledge and control of the CoG is what distinguishes experienced bladers from the weekenders who give it a few wobbly tries and give up. The secret is squatting, almost crouching. The closer your CoG is to the ground the easier it is to not fall. Standing straight up almost guarantees a fall. Falls in Lunar gravity at slow speed shouldn’t be too much of a problem. At faster speeds, mass is still mass irrespective of gravity, and when it hits something at speed it’s going to hurt. An often overlooked benefit of rollerblading is that balance is one of the most brain-intensive functions of the body, and rollerblading is an intensely balance oriented activity, making it a mind & body workout.
Martial arts also make active use of the body’s CoG, and the 1/6th Lunar gravity opens up a whole new realm of discipline. What moves are possible in the higher leaps and longer hang times found on the Moon? Many of today’s combat moves that are fiction in kung fu movies may see actual use on the Moon. This idea is explored in a strange episode of ‘Planetes’ entitled “The Lunar Flying Squirrels” (episode 6), which features prodigious and seemingly impossible leaps.
In ‘Welcome to Moonbase’, author Ben Bova explores a number of possible physical activities to help keep residents of the Moon fit and healthy for their return to Earth. The swimming pool is Olympic-sized, with an additional diving area and platforms at 10 m, 20 m, and 30 m. The water is drawn from the base water supply, and is purified with the abundant oxygen available once we figure out the best way to unbind it from the Lunar rocks and dust. One concern that has been raised in regards to swimming on the Moon is that when your head breaches the surface, gravity is not pulling the water off of your body (and face) as quickly as it would on Earth because of the lower gravity and surface tension. This might make breathing a bit problematic during competition, but without any way to properly research it the risk remains unknown.
In addition to tennis, there’s handball, jai alai, and volleyball. I would pay good money to see a women’s volleyball championship on the Moon. It’s noted that basketball hoops have been moved up to 10 m in the lunar courts, and the playing area includes the plexiglass walls of the court! Football has become linear football, played in the corriders of Moonbase with whatever small kickable object happens to be at hand. The author gives the rundown on what few rules there are. He also notes an annual Lunar Olympics.
‘Leap of Faith’ artist: Pat Rawlings
The Lunar Olympics is best exemplified by artist Pat Rawlings’ ‘Leap of Faith’, which is also a NASA lithograph entitled ‘The Lunar Games’ (HQL-431). On the back it explains some of the records to be set on the Moon: pole vaulting over 35 meters, long jumping 55 m and weightlifting an Earth-equivalent mass of 1,100 kilograms. Just a few years ago NASA made a push for a Lunar bid with ‘Lunar Olympics’ and Out of this World Olympics. ‘Science News for kids” even has a Lunar Olympics Challenge.
Cover: ‘Odyssey Magazine’,
April 1999 Art by Michael Carroll
Passing outside of large, enclosed spaces, perhaps in the form of domes or massive underground caverns, we venture onto the surface of the Moon. I can only imagine the tricks possible on a Lunar BMX course during the long hang time, an idea explored in the article “Lunar X Games”. Braver souls might want to try skiing or rego-boarding the local craters. While likely to be considered reckless, foolhardy, and putting expensive equipment at risk, it should also be recognized that the risk element, and its mitigation, in these ‘outdoor’ activities is going to be driving a lot of advances in vac-suit technology, making space safer for everyone.
The best example of Lunar sports to date is Alan Shepard’s golf outing at the Apollo 14 landing site (3.6S, 17.5W) in Fra Mauro. This is how he described it:
AS: “Uh Houston, while you’re looking that up, you might recognize what I have in my hand as the, uh, handle for the contingency sample return. I just so happen to have a genuine 6-iron on the bottom of it; in my left hand I have a little white pellet that’s familiar to millions of Americans. I drop it down. Unfortunately the suit is so stiff I can’t do this with two hands, but I’m going to try an old sandtrap shot here.”
EM: “You got more dirt than ball that time.”
AS: “A bit more dirt than ball; here we go again.”
MC: “That looks like a slice to me, Al.”
AS: “There we go! Straight as a die. One more. Miles and miles and miles!”
MC: “Very good, Al. And to answer to Ed’s earlier question about …”
Golfing is also mentioned in ‘Planetes’, and a golf course is one of the tourist attractions that can be built in ‘Moon Tycoon’. In the anime series Planetes, the Moon is treated in part as a waystation for microgravity workers, to get them reacquainted with gravity before heading back to Earth at the end of their contract, and as a hospital for those injured in space so they don’t have to go back into the gravity well of Earth to recover.
Rollerblading is very similar to ice skating, a traditional method of longer distance transport in more frigid climes here on Earth. If there are in fact deposits of ice at Lunar poles (unlikely; if it is water then the stuff will probably be more like frozen concrete than sheets of ice), then perhaps someone can set up a starlit ice rink in one of the everdark craters. It may seem a flight of fancy, but it is certainly a romantic notion and one that could be quite profitable in some distant Lunar future. Lest one think that space science is divorced from such Earthly concerns as ice-skating, in one of those serendipitous spinoffs so often found in the space field, NASA science has helped find a new way to edge skates to improve our athletes’ performance, in ‘Polished to Win’.
From ‘Where the Winds Sleep’ by
Neil Ruzic. artist: Donald G. Lewis
The true pleasure to be found on the Moon is flying. Suggested by Robert Heinlein in his short story ‘The Menace from Earth’ (a great sci-fi novelette, especially for the young ladies), it has been mentioned in any number of subsequent works, including “Where the Winds Sleep”, where the author notes that
“the first men to fly like birds did it exactly five seconds after Dome One at Alphonsus (13.4S, 2.8W) was pressurized on February 10, 2026.”
Heinlein describes a flight undertaken by young Holly Jones, 15 year-old spaceship designer on the Moon:
“I spread my wings, ran a few steps, warped for lift and grabbed air - lifted my feet and was airborne.
I sculled gently and let myself glide toward the air intake at the middle of the floor - the Baby’s Ladder, we call it, because you can ride the updraft clear to the roof, half a mile above, and never move a wing. When I felt it I leaned right, spoiling with right primaries, corrected,and settled in a counterclockwise soaring glide and let it carry me towards the roof…
Even without an updraft all a level glide takes is gentle sculling with your finger tips to maintain air speed; a feeble old lady could do it. The lift comes from differential air pressures but you don’t have to understand it; you just scull a little and the air supports you, as if you were lying in an utterly perfect bed. Sculling keeps you moving forward just like sculling a rowboat…or so I’m told…
But when you’re really flying, you scull with forearms as well as hands and add power with your shoulder muscles. Instead of only the outer quills of your primaries changing pitch (as in gliding), now your primaries and secondaries clear back to the joint warp sharply on each downbeat and recovery; they no longer lift, they force you forward - while your weight is carried by your scapulars, upunder your armpits.
So you fly faster, or climb, or both, through controlling your angle of attack with your feet - with the tail surfaces you wear on your feet, I mean.
Oh dear, this sounds complicated and isn’t - you just do it. You fly exactly as a bird flies. Baby birds can learn it and they aren’t very bright. Anyhow, it’s easy as breathing after you learn…and more fun than you can imagine!”
Sounds like it to me. I have a feeling that flying will be the most highly anticipated activity on the Moon. Just as the Moon is carved into the human spirit and culture, so too is the desire to fly, and as technology advanced, so too did the means to do so. It’s not a question of If, but rather When we will fly on the Moon, and that will likely be as soon as there’s a sufficiently large enough pressurized space to try. I’m just wondering what the birds we take with us out into space are going to think about it, and if they’ll start playing with us even more than they do now.
Until such time as there’s a sizeable enclosed space, we’ll have to make due with rollerblading on the Moon.
NB: A couple other sites that showed up during research:
Lunar Sports (doc)
Playing Sports on the Moon
Sports on the Moon
“95 Worlds and Counting” takes viewers on an “extreme sports” tour of the moons of the Solar system.
That’s right Ladies and Gentlemen, the weekly Carnival of Space, which has twice (#18 & #31) stopped by Out of the Cradle, is rapidly approaching it’s 52nd week, making for its first anniversary. It just keeps getting bigger and better, with more and more space writers joining in!
This week it’s over at AstroEngine, and there’s quite a line-up of articles, including the third part of “Of a Garden on the Moon” from here at OotC. Next week it will be at CoS Central, Universe Today, which also hosts the archives.
[Whoops! My bad - it’s at the site of its genesis, “Why Homeschool”]
It has been an incredible first year, and provides a nice perspective on the growth in independent space content that the internet is uniquely configured to deliver. It has also provided a greater sense of community for people to feel comfortable writing about space and sharing their thoughts. So be a part of the community and send a link to your space-related writing to carnivalofspace@gmail.com. And if you want to really be cool, send an e-mail to Fraser over at info@universetoday.com and tell him you’d like to host a Carnival of Space for a week. The world will be a better place for it.
or: The quest for answers continues
In our quest to answer the question of whether plants can grow in Lunar regolith, the main obstacle to a definitive answer seems to be that we are limited in our research by the availability of actual Moon dirt to work with. This time around we’re going to look through NASA’s Lunar e-Library to see if we can find anything of interest, and also do a little speculating on what some of the possibilities might be for Lunar agriculture (cynthiculture?).
…
Okay, that didn’t work so well. I’ve always had problems with the Lunar e-Library CD, and it makes my hard drive make odd and unsettling sounds. The index is one of the few things I’ve ever been able to get to work, and a search only revealed a couple of papers that might be of interest. I tried about half a dozen times to retrieve the files, but haven’t been able to do so. These were:
Ito, T., “Nutritional characteristics of moon dust for soil microorganisms”, N86-14078, 09/01/83 (pdf)
and
“Utilization of on-site resources for Regenerative Life Support Systems at a lunar outpost.” Abstract Only.
I didn’t see the Ito paper referenced in the LBA:SfPG in part II. Reading through it, it does seem to be tough to draw any conclusions from it. Well, perhaps the NASA Technical Reports Server has something else. Nope, not much there either. The impression I’m getting is that most of the research in the past couple of decades has been focused more on creating artificial growing environments for use on space stations (which is entirely reasonable given that we actually have space stations to work with). The use of regolith as a growing medium, or as a supplement to a plant’s growing medium, seems to have been largely overlooked, probably because of the difficulty in obtaining use of the real stuff as noted in Part I & Part II. I did do some digging around on the internet and did come across a couple of items of note:
The one I’m really impressed with is NCSU’s “Adventures of the Agronauts”, which is a set of curriculum materials involving plant growth chambers for space. Mission 3: “Stayin’ Alive (Pt. I)” (doc) covers the discussion of soils, and is very nicely done for the target level audience (elementary). I’m not sure if this is in response to NASA’s “Lunar Plant Growth Chamber Challenge”, which has been getting a fair amount of traffic over at the Lunar Library.
At a far more advanced level, ‘In Situ Biological Response: Scalable Assay of Complex Biological Phenomena Using Genetically Engineered Plants’ (pdf) by Paul, Schuerger and Ferl at the Univ. of Florida and presented at the 2005 Space Resources Roundtable offers some interesting insights. For example, I did not know that seeds could travel in vacuum and at extremely low temperatures. Their proposal seems to be for a lander that would scoop up some local soil and plant the seeds in them. The plants would have been genetically engineered to provide a specific response, such as Green Fluorescent Protein (GFP), upon the activation of certain gene sequences. In this way the plant could act as a biosensor to measure bioresponse to these new environments. This seems to be a really interesting path of research to follow.
Not directly applicable, but speaking to the limitations of simulants as a research material, is the book of abstracts for the “Lunar Regolith Simulant Materials Workshop” (pdf), which was held back in January 2005.
I would be remiss if I didn’t also mention a nice NASA Educational Informational Product entitled “Teachers and Students Investigating Plants in Space: A Teacher’s Guide with Activities for Life Sciences” (pdf). While it doesn’t speak to Moon regolith as a growth medium, it is nevertheless a great introduction for students (Gr. 6-12) to learn more about plants in space.
Still another resource is something I got from my online Moon class last fall, a WJU project entitled “Bio-Blast”.
Al Fin joins in the discussion and notes that I didn’t mention aeroponics as a potential means for growing plants on the Moon in his post Planting a Garden On the Moon and CoS 49
There must be some kind of zeitgeist going on here, as the BBC just published an article entitled “Plants ‘thrive’ on Moon rock diet”. (hat-tip to Clark over at the indispensable Hobbyspace) It describes research presented at the European Geosciences Union meeting in Vienna (a very interesting city). Marigolds were planted in anorthosite, a common rock in the highlands of the Moon, and in the presence of microbes the plants thrived. One unnamed senior official of the European Space Agency (ESA) apparently dismissed it as ’science fiction’. I think the research presented in this three-parter shows that the idea of growing plants on the Moon has some pretty compelling, if sparse, science fact behind it. As has also been shown, we do have to be careful about drawing conclusions when using simulants. I’ll see if I can get a copy of the presentation from Mr. Foing for the Lunar Library.
In the first part, I noted that the Moon pretty much couldn’t support life. That is not entirely true. In Volume 4 of NASA SP-509: “Space Resources”, on page 262 is an extract taken from a paper presented at the 2nd Conference on Lunar Bases and Space Activities of the 21st Century, ‘Water and Cheese from the Lunar Desert: Abundances and Accessibility of H, C, and N on the Moon’ which notes:
“The Moon has been underrated as a source of hydrogen, carbon, nitrogen, and other elements essential to support life. Each cubic meter of typical lunar soil contains the chemical equivalent of lunch for two - two large cheese sandwiches, two 12-oz. sodas (sweetened with sugar), and two plums, with substantial carbon and nitrogen left over.”
Speculation:
Absent definitive answers, all one can do is speculate based on the limited available facts, as well as present idealized cases.
It’s generally understood that any kind of long-term Lunar presence is going to be underground. Barring the propitious discovery of underground caverns, perhaps from old lava tubes, we’re going to have to carve that space out of rock and seal it. The mental well being of Moonbase residents is going to dictate that people have access to greenspace, so it is only logical that at some point people are going to carve out large enough spaces to support a more natural type of agriculture than the types of CELSS systems noted in part II. More adventurous types will want large spaces in which to fly. So at some point we’re going to be looking at planting large amounts of plants in what will mostly be (at first) sterile Moon dirt.
 An interesting philosophy in relation to the raising of plants as foodstuffs is the French concept of terroir and goût de terroir. The concept is, in essence, that the taste and quality of a foodstuff is a function of many factors, primarily the soil in which the plant is grown and the minerals therein. Contributing factors include the angle and time of sunlight, humidity of prevailing winds over the growing cycle, timing of rain, and many other factors. Applying the lessons of CELSS, we can consider how the large underground spaces might be designed. The use of lightpipes mounted on Solar Power Towers to direct raw sunlight underground allows for control of the spectra and timing of sunlight received by the plants. Sprinkler systems mounted on the ceiling can provide periodic rain showers. Venting of waste atmosphere from the base and uptake of cleaned atmosphere from the plants might be controlled (how I have no idea). In many ways, different micro-terroirs could be created to craft particular foodstuffs.
Fresh fruits and vegetables are always in demand at the ISS, as was the case with Mir, and will no doubt be the case at future cislunar orbital facilities between the Earth and Moon. It’s cheaper to launch cargo from the Moon than from Earth, so there is a natural trade flow from the Moon once we do get around to large scale plant production. This also bodes well for future Lunar restaurants, who will be able to provide menu items unique to the Moon for tourists, as well as other plant delights (Moon perfumes? New spices? Lunajuana?).
So what do I think happened with the liverwort way back in part I? I can’t claim to be any kind of expert on this topic, but my speculative guess is that the thoroughly “gardened” Lunar regolith is abundant in a lot of trace elements (the same sorts of things we take vitamins for) that have been farmed out of the soil at industrial farms here on Earth. That abundance of trace minerals helps for gene expression and cell function in both plants and humans. The Moon may actually be a gold mine for agriculture, both there and here.
-Given the abundance of trace minerals, would it be feasible to export quantities of regolith back to Earth to serve as a soil supplement for terrestrial fields?
-Given the apparent harshness of the Martian soil, would it be feasible to export quantities of Lunar regolith to Mars, in conjunction with small amounts of Earth humus, to serve as a soil medium for greenhouses there?
-Will regolith be used in conjunction with microgravity materials sciences in cislunar space to create even more efficient growth media for plants, a la zeolites? (Future marketing: The “Z” in zeolites is for Zero Gravity! Buy now!)
Another interesting consideration is that research has shown that plants grown in space can manifest physical properties unseen on Earth. In particular, a rose was found to have a significant change in some of the chemical components. Microgravity is a lot different from one-sixth Lunar gravity, but Lunar gravity is a lot different from Earth gravity - it’s wonderful. (I know this to be so very, very true from my Zero-G flight - the Lunar G parabolas seemed to be everyone’s favorite, as Mars was too much like Earth, and micro G was just alien to the body {doesn’t mean I wouldn’t do it again in a heartbeat, as many times as possible})
On a more philosophical level, it’s also exciting to consider the cosmological import of bearing the seeds of Earth out into space. Do we have a right to carry the life of Earth out into the Solar system where there is no life? Or is it an obligation we have as the intelligent caretakers and stewards of the Earth’s ecosystem to grow that ecosystem beyond Earth?
I can easily envision large underground spaces in the Moon where guinea pigs and bunny rabbits frolic in the gardens amongst butterflies and ladybugs and ants and earthworms and flowers. It seems a long ways off from where we are right now, but it can happen, and probably will because someone in this world will do it. This begs the question of what parts of the biosphere we will take with us; not an easy question to answer.
Who know what kinds of exciting discoveries await us in this largely unexplored field of Moon farming? (which I’m going to start calling cynthiculture because it sounds cool) This is pretty much Luna Incognito at this point, which means there are a lot of exciting opportunities for discovery. Who will be our Johnny (or Jane) Appleseed of the Moon?
Librarian’s Note: The inspiration for this article came from a confluence of circumstances. In no particular order:
-I’ve noticed a fair amount of traffic through the NASA Lunar Plant Growth Chamber Challenge entry over in the Lunar Library
-I’ve been working my way through the English-language translation of a book by Pierre Boulle (author of ‘Planet of the Apes’) entitled ‘Garden on the Moon‘ [It turns out to be a Zen garden] for the Lunar SciFi reviews (Wow, over 100,000 page views to date!) over in the Forums
-Doing a review of ‘Lunar Base Agriculture‘ has been on my to-do list for a while
-After serving as a judge at the recent Dallas Regional Science and Engineering Fair, I was wandering around looking at the other displays outside of my judging section (high school physics & astronomy) and in the junior high area (which I judged last year) was a display entitled ‘Operation Moon Dirt: Can the Man and the Moon take up Farming?’ I remembered the news article that was his inspiration for his investigation, and he had an impressive write-up and display. He got 2nd place in his division. Way to go!
-I was going to do a review of available non-Apollo-specific documentaries that are available, but it’s all the same stuff and I got bored and moved on to something more interesting. Still, that video segment of the liverwort response noted in part I of the article was sufficiently different that it has been sticking in my head.
-I was looking up something else in the Oxford Dictionary of Astronomy and stumbled upon ‘Cynthian’ - “referring to the Moon. The term comes from an identification of the Moon goddess with Artemis, twin sister of Apollo, supposedly born on Mount Cynthus on the island of Delos.”
-I got distracted from another article I’m working on about exercise on the Moon because I can’t find the DVD that has the rego-boarding sequence in it.
Thanks everyone for reading! Please feel free to stick around and browse through the stacks over at the Lunar Library.
Coming Soon! Out of the Cradle’s next feature article - “Rollerblading on the Moon”
Part I
Part II
P.S. Readers are invited/encouraged to leave additional related links in the Comments.
or: Let’s consult the most comprehensive text to date.
Henninger et al’s “Lunar Base Agriculture: Soils for Lunar Plant Growth”, published in 1989 by the American Society of Agronomy, the Crop Science Society of America, and the Soil Science Society of America, weighing in at 255 pages. I’m not qualified enough to determine if there were factual errors hidden in the text, but no typographical errors were noted.
This seems to be the definitive reference with regards to growing stuff in regolith. It starts out by looking at some strategies for getting to the Moon (& Mars), and how to set up shop there. The book then gives an overview of the conditions at the Lunar surface, covering things like the (exceedingly faint) atmosphere, what little magnetic fields there are, the abundant radiation, and micrometeorite flux. Next up is the mineralogical and chemical properties of the Lunar regolith. While this book pre-dates the ‘Lunar Sourcebook’, this chapter is a pretty good summary of what is in the ‘Sourcebook’, with great scanning-electron microscope photos throughout.
Finally, we get to the plants with ‘Pedology [science of soils], Pedogenesis, and the Lunar Surface’. The article’s authors note some of the very good reasons for growing plants at a Lunar base:
“physical support, nutrient reserves, buffering capacity, low maintenance, medium for recycling waste by-products, and nutrient recycling.”
We get an intro to soil concepts, and then they apply the facts of regolith to those concepts. We get such fascinating insights as
“In an Earth-like environment, chemical weathering would be expected to occur because lunar minerals are not currently in equilibrium with an Earth-like environment. Minerals common to the [L]unar surface are among the least stable in terrestrial soils and sediments.”
Finishing up the authors note some items for additional study, like the effect of gravity other than 1g on plant growth. Perhaps a future science fair project would be to create a centrifuge of plant growth chambers to try to simulate a 1/6th gravity while growing plants.
Next is a survey of ‘Nutrient Availability and Element Toxicity in Lunar-Derived Soils’. The authors note the sixteen elements generally considered essential for plant growth, the macronutrients like C, H and O, and micronutrients like Fe, Mn, Zn and B, as well as four supplemental elements found to be beneficial such as Na and Si. We find out that the pH for Lunar dust is 6.32, just a bit under basalt’s 6.6 pH. I like the conclusion, even if it’s not all good:
“The composition of lunar soils and the dissolution properties of the lunar dust studied by Keller and Huang (1971) indicate that a lunar soil has the potential to be an excellent medium for the growth of higher plants. The lunar soil, when exposed to a moist, aerobic, Earth-like environment, can be the source for many of the plant essential nutrients. Additions of N and to a lesser degree, P and K, will be necessary for optimum growth of higher plants. Higher natural concentrations and potential dissolution of certain trace metals, particularly Cr and Ni, may prove toxic to plants and bacteria.”
So there is a note of caution, but overall that seems to be in line with what was shown in the video noted in the first part. The authors do note
“A better indication of the nutrient-supplying ability of lunar soils could be found by measuring the plant-available fraction with extractants common to plant and soil analyses…(list of extractants)…Unfortunately, no such analyses have been performed on the samples of lunar soil collected by the apollo [sic] missions.”
Here we find that part of the reason we still don’t know whether plants are growable in Moon dust is that certain tests we would routinely apply here on Earth haven’t been conducted on the Moon dust. Something to look for in later research.
The next chapter then considers some of the risks identified in the previous chapter, and suggests using ‘Manufactured Soils at a Lunar Base’. Here we get some background on the promising field of zeolites. In this case, the appropriate nutrients are extracted from the Moon dirt and ‘caged’ by the zeolite structure for delivery to plants, while the risky stuff, like excess chromium, is kept away from the plants. It seems rather complicated, if promising, and unlikely something we would be doing right from the start given other priorities for a Moon base.
Next up is a look at ‘Controlled Environment Crop Production: Hydroponic vs. Lunar Regolith’. Here, the authors note that their
“ultimate goal of higher plant research in a CELSS is to remove environmental constraints such that the photosynthetic photon flux (PPF) is the only factor limiting growth and yield.”
So the goal is to produce the greatest amount of edible biomass in the smallest volume possible. We get a thorough overview of hydroponics systems, which the authors note “is widely used to grow high-input specialty crops on the Earth”. They suggest that regolith may help to provide a better root-zone environment for crops, but also note that inorganic salts may be an important consideration, as they are required for plant growth and will need to be shipped up from Earth to be added to the Moon dirt. Criticisms of hydroponics systems are noted, and that their requirements add complexity. The authors, who were researchers at the university that developed the Apogee Wheat noted in the first part, conclude that
“Plant growth in lunar-derived soils is a most interesting topic, but it will be extremely challenging to modify these soils to provide the same root-zone control and optimization that is readily obtained with hydroponic culture…Lunar soil may also provide valuable options for microbial waste recycling.”
So the next chapter looks at ‘Microorganisms and the Growth of Higher Plants in Lunar-Derived Soils’. Here, the thesis is that
“On Earth, microbes are the major biological agents responsible for the conversion of primary minerals into soil. The basic similarities in the composition of terrestrial bedrock and the [L]unar parent bedrock and regolith [refs.] suggest that the latter could be converted into an acceptable soil to support plant growth in an enclosed environment on the Moon if water, energy sources (e.g. from plant and animal wastes), and other factors necessary for the growth and activity of microbes are provided…”
Some relevant microbes and enzymes are identified, though a case is made for GEMS - genetically engineered microorganisms. Ultimately, the author admits that much research needs to be done regarding the role of microbes in converting regolith into functioning soil. Interestingly, he notes a point that I made in the first part:
“The current reluctance to use the limited amount of regolith available (ca. 333 kg ) for such experimentation is understandable. However, the risks are too great to base the designs and predictions of a successful lunar base, that will have to grow its own food and dispose efficaciously of its wastes, solely on studies with simulants.”
To look further into these soil workers, we then venture to the ‘Role of Microbes to Condition Lunar Regolith for Plant Cultivation’. The author give a list of 26 trace elements considered essential or growth stimulating for plants, and what the specific function of each one is, and then gives examples of microorganisms that can mobilize these trace elements from minerals. Lunar minerals that could supply these elements are identified, as well as noting two that seem to be in short supply - Molybdenum and Boron, though checking the ‘Lunar Sourcebook’ it seems that there’s just been little data collected on these elements because of their behavior in Lunar rocks, and some of what little data there is may be unreliable. The author notes that while there may be some risk to plants of concentrations of potentially toxic in large amounts elements, such as chromium, Mother Nature seems to have provided a counterbalance in the form of microbial reactions that can reduce that concentration.
 In the next chapter, NASA HQ gives us an overview of a ‘Controlled Ecological Life Support System’, which from the photo is the same one I saw down at Cape Canaveral as noted in the first part of the article. This is further explored in ‘CELSS Breadboard Project at the Kennedy Space Center’, which goes into the engineering and operations of the facility. Activities to date (1989) are covered in ‘The CELSS Research Program: A Brief Review of Recent Activities’, largely covering the wheat activities noted earlier, but also expanding to some other higher plants, such as duckweed. We close out the exploration of closing the loop on life support systems with ‘Life Support Systems Research at the Johnson Space Center’. Here we get back to the idea of using Lunar regolith, though the author notes that experiments into the effects of various solvents will be conducted on simulant materials, which calls the results into question, and the author does cover the weaknesses. Looking forward, the author covers a number of the engineering solutions that have been developed to help humans live in a closed environment away from Earth.
Returning more fully to the realm of plant growth in Moon dirt, chapter 15 looks at ‘Physical and Chemical Considerations for the Development of Lunar-Derived Soils’, largely from the context of the functions of rooting media. Particular treatments are prescribed to remove some of the more deleterious elements in the regolith, and what the physical, chemical, and nutrient considerations are. In this chapter we get nice overviews of many of the important nutrients, and comparisons between Earth soils and Moon dirt, making this quite a valuable chapter, and the authors note a number of future areas of research.
One area of these research needs is examined in ‘Geochemistry of Soils for Lunar Base Agriculture: Future Research Needs’. This looks at the mineralogic, lithologic, chemical, physical and textural characterisitics, and notes that much research needs to be done into the dissolution of primary minerals and glass in Lunar minerals, precipitation of colloids, redox change, metal translocation, and other advanced soil research areas. The authors conclude that “the soils formed from [L]unar regolith in the CELSS environment will constitute a large experimental system in which many variables and processes cannot be understood in advance”, but note that carefully constructed experiments with analog simulants can provide usable knowledge that will help us focus future research.
 We move from the realm of inorganic rocks to organic plants in the next chapter, on ‘Plant Considerations for Lunar Base Agriculture’. This provides an overview of many of the considerations for choosing which plants to use in a CELSS, and how the unique characteristics of off-Earth environments also need to be considered in the choices. We end with ‘Microbiological Considerations for Lunar-Derived Soils’, which summarized some of the earlier material, but focuses on the Nitrogen Cycle in the plant-growth process. As with many of the other authors, those of this chapter reiterate that using simulants will provide only limited speculative contributions to our knowledge base. Experiments with real Lunar materials will assuredly be exciting.
So there’s a lot of plant-related material to digest, so to speak. This is pretty much the definitive text to date for Moon-based agriculture, but it is pretty frank in stating that research needs to be done with actual Lunar materials. This raises the question of what priorities we have for the use of the Lunar materials we’ve hoarded to date, given that if we are going back to the Moon then we’ll be able to get more. Clearly the priority needs to be given to that research which provides the best results relating to a return to the Moon (which greenhouses is unlikely to be a part of in the nearest term). This is complicated by the fact that if we are going to start out this time around by going to the poles instead of the equator, then we’re likely looking at different sample types, so the results from the equatorial samples might not be ideal for preparing for the polar environment. Still, we’ve got to work with what we have.
 As far as the review goes, I have to say that for researchers in the field it might not be quite as useful as hoped (such as if they’d been allowed to use the real stuff for the project), but still the best you’ve got to work with right now. It should definitely be used in conjunction with the ‘Lunar Sourcebook’, which thankfully LPI has made available on CD to alleviate the sticker-shock of the hardbound version. Some of the chapters seem to be used as platforms for the authors to promote particular approaches moreso than report on study data, and overall the amount of info directly relating to Moon dirt is not quite as extensive as could have been hoped for. That being said, the useful chapters are really, really useful, and provide a great introduction to how the Moon dirt compares with Earth soil and why it’s important, making it a great investment for those who want to learn more.
Given that it is really the definitive book to date on the subject, and the quality of the really good chapters, it gets a Full Moon, but I’m going to qualify it as a Full Moon at apogee in anticipation of a more definitive work based on the use of real regolith.
Next time around we’ll try to find some more recent work (post-1989) on the subject, and engage in a little speculation on the future of agriculture on the Moon in:
Of a Garden on the Moon, part III
or: The quest for answers continues
Part I
“Moonlight Mile Vol. 2: A Gambler’s Moon”
The story of Goro and Lostman continues on their quest to attain new peaks of achievement. After the H-III blows up in Japan, Goro ends up at Star City in Russia on the crew of the shuttle Gagarin. The Gagarin is a bit beat up after a bad launch (well worth the view), and Goro puts the odds of a successful launch at 50/50. Good enough for him. He also meets a girl who may be his equal, and who dances to keep him safe as he launches to the station.
What a work site! Once the first step was established they’ve continued to add to the station, making it quite impressive. Ongoing preparations for the Moon mean that Goro is frequently on EVA, and gets to have a little excitement that takes him even closer to the Moon (more than once). Space is a new frontier for humanity, and the dangers are constant. Even being there is a gamble.
“Space is a vast, beautiful and terrifying place.”
“And that’s why gamblers like us will always call it home.”
Lostman finds his military background helps to serve his ends, and he suddenly finds himself moved from fifth-string back-up pilot to flight pilot on the next Odyssey launch to take needed supplies for the civilian effort to start construction of a Moon base. A glitch in the software puts the shuttle badly off course. Can Lostman’s skills save them?
The crises continue apace, and our heroes find themselves saving the day again. The launch of a private German contribution to the Nexus Project goes awry, leaving an astronaut trapped in an orbit that will end with an enormous impact in Sydney, Australia. The whole world waits with bated breath…
Wow. This continues to be a powerful story of adventure in near-Earth space. As with the first DVD, there are many flash-forwards, some explained over the course of the DVD, others left unrevealed. Goro is the philosopher poet, crass, vulgar, and profane, who nevertheless has the best lines in the story. Lostman continues to develop as an enigmatic character, cold-blooded but nevertheless always in the thick of doing the right thing. Purists might find that the shuttle has developed quite a bit of maneuverability, but it’s to advance the dramatic story, not the scientific story, so just chill out. It’s not the machines that are important, but the Men and Women who use these tools to advance humanity out into the high frontier.
Quite adult, with ample amounts of what I guess could be phrased as ‘graphic’ nudity, ample vulgarity with the F-bomb sprinkled throughout, and lots of adult situations. I’m guessing that folks behind this one are rushing it to market, as there were assorted spelling errors in odd places in the signage in the background. Not fast enough as far I’m concerned - I’m quite ready for the next one.
We’re not even to the Moon yet, but close, so very close. I haven’t enjoyed a near-Earth, near-future story like this in a while. And so like a shimmering beacon still just a bit out of reach, I’ll bump the rating up to Full Moon at apogee.
Part I
or: How are we going to grow plants in sterile rock dust?
One of the key questions for early Lunar selenologists was whether or not the regolith of the Moon could support life. The results were pretty conclusively no, as most of the elements that we consider important for life such as carbon and nitrogen are scarce to be found. This would seem to make the Moon a pretty rotten place to try to grow plants, but there’s a strong likelihood that the Moon could turn out to be a fantastic place to grow the plants of Earth.
Early settlers are going to be looking to go deep underground on the Moon, with lots of rock above them to protect them from the vacuum and radiation. This does not mean that Moon dwellers will end up as troglodytes, as modern technology has given us many tools to work with that can help us create a subselenian paradise on the Moon.
While early plans for a Moonbase typically settled for an near-equatorial location to help keep the orbital mechanics easy and resupply cheap, newer ways of looking at how we return to the Moon, such as using an Earth-Moon L-1 platform as a staging location, are giving increasing consideration to polar locations. The difficulty of access is offset by what appears to be large supplies of hydrogen (in some form, currently unknown but hoped to be water) in the everdark craters at the North and South poles. There appears to be more at the North pole, but the more rugged terrain of the South pole, perched on the rim of the Aitken Basin, offers more interesting opportunities.
Not only are there deep, dark and cold craters where the Sun never shines, but there are also mountains and plateaus where the Sun shines nearly all the time. So instead of lugging lots of heavy batteries or a heavy nuclear reactor to the Moon to supply energy through the long Lunar night, you instead ship up Solar panels, erect tall towers to peek over the horizon, and hang your Solar arrays out to collect the abundant sunlight all the time. Other equipment can be mounted on these ‘power towers’, such as Solar ovens, which use mirrors to focus lots of sunlight onto a small area to achieve very high temperatures, and lightpipes.
 Lightpipes are a technology used today here on Earth in modern buildings. An inlet for the sunlight is at the top of the building, and via a series of mirrors and ducts the sunlight is directed to the inside of the building. On the Moon these could be mounted on the power towers, directing raw sunlight deep underground that can be used in part to illuminate crops in caves deep beneath the surface. Other lighting options include light-emitting diodes, full-spectrum fluorescents, and traditional incandescent. So we don’t really lack for a light source on the Moon, and we know how to carve caves underground.
Water is problematic. It is hoped that the hydrogen abundances found at the poles are water, but even if they aren’t the hydrogen can still be harvested, and oxygen can be wrested in abundance from the Lunar rocks. Thus, the constituents for water will be available at the poles, the problem, just like here on Earth, is keeping it clean enough for humans to consume. Chemical treatments are quite advanced, and in the name of science NASA scientists have drunk water purified from their own urine. Still, maybe there are additional ways to treat the water to make it more palatable.
Which brings us back to the plants. Part of the water treatment cycle may involve watering plants with ‘grey’ or non-potable water from the treatment facilities, and then collecting the water that they transpire into the air, perhaps even controlling the humidity to encourage such transpiration.
There are two main types of seleneculture generally considered: hydroponic and soil-based. As its name implies, hydroponics relies primarily on water-delivery of nutrients to the naked roots of different plants. This style of growing plants has been extensively studied by NASA scientists as a means of providing a high-efficiency/low-mass greenhouse for a space station, and is used in industrial farming here on Earth. It may not be ideally suited for the Moon, but would certainly provide a quick way to get started.
Soil-based plant cultivation uses plants in dirt. The most frequent objection in this case is that plants can’t grow in Moon-dirt, so you’d have to ship up tons of Earth dirt for the plants to grow in. This will certainly be true in the beginning though not to the tune of tons, and we probably will be shipping up small quantities of high quality humus. Still, is it true that plants cannot grow in Moon dirt?
We’ll start the investigation with a documentary that is pretty dated in style, but definitely not in content, NASA HQ 209: “Moon, Old and New”, available on the DVD “The NASA Collection”. This documentary features a short bit (00:18:13 to 00:19:21) from Dr. Charles H. Walkinshaw, who comments that:
“Of the variety of biological systems that we tested with the Lunar material, the plants were most unique in their response. For example, the five jars of liverwort that you see illustrated on the top gave much increased growth in the presence of Lunar material. This effect was noted for ferns, a number of tissue cultures such as tobacco and corn, and certain higher plant species such as lettuce. Now the exact reasons for this beneficial response are unknown at the present. However, it is likely that some trace mineral, or perhaps even a physical property of the Lunar material is interacting with the minerals we furnish to give a more desirable medium for plant growth. This is a very exciting discovery and one that was totally unexpected in the tests conducted in the Lunar Receiving Laboratory.”
Contrast this with comments by Dr. Bevan French, who worked on both Apollo and Luna samples. In his 1977 book “The Moon Book” he states:
“Even the plants grown in [L]unar soil back on [E]arth had to have nutrient solutions added*
*Early reports that some terrestrial plants showed increased growth rates when grown in [L]unar soil have not been substantiated by later experiments. Almost everything that a plant needs for growth (water, organic compounds, potassium, etc.) has to be added to the soil to make the plants grow at all.”
I do wonder if Mr. French thinks that plants don’t often need things like water and fertilizer back here on Earth. So the question still remains, even if the video is pretty compelling evidence. So I delve deeper into the Lunar Library. Checking the papers from the Apollo 11 Lunar Science Conference I see only the search for organic elements, which IIRC didn’t yield much at all, on the order of parts per billion, mostly implanted by the Solar wind. The granddaddy of Lunar references, “Lunar Sourcebook: a user’s guide to the [M]oon”, doesn’t say anything about plants, nor really do any of the references in the Selenology section of the LL.
Time to check the Moonbase section. “Outpost on Apollo’s Moon” from 1993 has a short section on efforts at KSC during the 1980s and into the 90s and beyond that showed the viability of growing plants in an enclosed space. [I actually got to see that chamber, which is really tiny, during a field trip of the NASA Academy. It’s also where I picked up a couple of packets of Perigee Wheat] The author, Eric Burgess, doesn’t really speak much to the use of regolith as a plant growth medium other than to note that it could be used in a Lunar Closed/Controlled-Environment Life Support System (CELSS) supplemented by nutrients and minerals brought from Earth.
“The Moon: Resources, Future Development, and Settlement” by Schrunk, Sharpe, Cooper (who has autographed my copy), and Thangavelu, has a short section on Lunar agriculture on p. 45, where they note that a food crop cycle has not been successfully conducted off-Earth, though plants have been grown in microgravity. They propose some active investigation across an array of variables to determine the viability of Lunar regolith for plant growth.
And here we run into one of the hurdles to experimentation. Most of the actual Moon dirt is tightly secured, and only something like 15% of the actual samples have been closely investigated, with the rest saved for the future. Until such time as we are actively getting new samples from the Moon, we probably shouldn’t be using up too much of what we do have carefully hoarded away. Furthermore, use of the regolith would be destructive to the sample since it would be changed by its interaction with the plant roots, and you would need a fair amount to test across a number of variables. So the current supply of Moon dirt isn’t necessarily going to allow any kind of real or robust investigation.
 Which leads us to the second hurdle, that of the use of simulants. “The Moon: RFD&S” has an excellent on the different kinds of simulants that are available, and what sorts of experimentation they’re best suited for, and I know from the last LEAG conference that knowing the kind of simulant used is important and understanding their limitations is on NASA’s radar. This is perhaps in response to some recent experimentation whereby a researcher, perhaps perusing an online article on yet another microwaved this or that, decided to plop some real regolith on a saucer and stick it in the microwave oven in the break room. Lo and behold, it melted faster than a mug of water can boil! Rock! What is going on?
Turns out that when nickel-iron metorites impact the Moon they end up in part as a mist of nano-scale (or near nano-scale) iron that ends up coating everything around the impact site. Given the number of impacts on the Moon, and if the frequency of nickel-iron asteroids is the same as what we’ve found (so far) here on Earth, then about 5% or so of those craters are from nickel-iron objects. So pretty much all of the regolith has these ultra-small bits of iron on them, which happen to react energetically with the microwaves (plasma and all that, what you see when you accidently microwave metalware) and heat up the dirt until it melts. This is not something you’d see on Earth dirt.
This will probably be very useful once we get back to the Moon, as it means we can do things like mount the travelling-wave-tube apparatus from the microwave oven on a rover and have it ‘pave’ landing sites that can be kept free of dust, or roads leading to other work sites. This also shows that there are still a lot of unknowns when it comes to our samples from the Moon, and the investigations are far from over.
“The Lunar Base Handbook” by Peter Eckart has an extensive section on food production requirements at a Lunar facility, but in the section on Plant Growth Media beginning on p. 401 the author only considers Earth-like and artificial soils, and hydroponics and aeroponics, and refers readers to…
Next time:
Of a Garden on the Moon, part II
or: Let’s consult the most comprehensive text to date.
PartIII
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