Lunar Development

Learning from Those Who Have Been There

Dwayne Day has an interesting new article "Working on the Moon", about NASA taking the drastic step of actually asking the Apollo astronauts for their input on lunar surface equipment and other issues involved in the return to the Moon.

Their main complaint seemed to be the gloves. One possible solution was to lower the air pressure in the suits and use pure oxygen in them. This is an excellent idea, air pressure should be kept as low as possible in all equipment used on the lunar surface. Higher than necessary air pressure wastes resources, pollutes the lunar atmosphere and makes operations more difficult.

They also complained about the lunar dust. Lunar dust destroys mechanics is hard to remove and causes breathing problems. Going forward we should look at this as three separate problems.

1. How do we deal with dust for the initial landing to a location?

2 How do we seal the regolith at locations we wish to operate at so there is no routine dust exposure?

3. How do we deal with dusk long term for those who must be exposed to lunar dust like miners or geologists?

Answer number 1 might include disposable space suits, a door mat and a brush for dust removable kept outside the lander to clean dust off and a tent inside the lander for suit removal. The answer for Number 2 might be fused regolith tiles or fusing regolith in place, and possibly some use of gravel from mining slag.  The hard question is number 3, sure we can do dust locks to keep dust out of the interior of a Moon base, but how do we cost effectively deal with or prevent constant damage to space suits from lunar dust? Looking at the dust problem in three pieces make it more manageable.

Day describes a two disturbing syndromes at NASA.

Mary Connors, of Ames Research Center, and Dean Eppler of Johnson Space Center, explained that they conducted the study to offset what they called two “syndromes that affected some (by no means all) people in the exploration program.”

The first was what they called Apollo Nostalgia Syndrome, or Appollonious Memorilapsus, an affliction that struck white males in the 50–60 year age range who could remember little about what, if anything, they had done with Apollo EVA.

The second was Apollo Ignorance Syndrome, Appollonious Ignoramous, which struck white males under 40 who had been with the agency less than ten years. “Symptoms are a blank expression, and the repetition of the phrase, ‘What do you mean we went to the moon once!?’”Mary Connors, of Ames Research Center, and Dean Eppler of Johnson Space Center, explained that they conducted the study to offset what they called two “syndromes that affected some (by no means all) people in the exploration program.”

NASA has not paid attention to the Moon in a long time but the extent of memory loss and ignorance is disturbing. To even joke like this is scary. It  is a good thing we are not rushing back to the Moon.

Space Suits

Three interesting links about space suits.

Collect Space has an article about air force Manned Orbiting Labratory (MOL) space suits found at Cape Canaveral Air Force Station in a store room.

You can own a  replica space suit.

NASA is looking for a new space suit provider.

Dust in the Solar Wind, Metaphor and Reality

There is a lot of articles about Moon Dust Some as metaphore some about the reality.

There is a new book called Moondust: In Search of the Men Who Fell to Earth By Andrew Smith, about the remaining Apollo Astronauts and what they are up to.

Here are some reviews- Robin McKie ,Christopher Silvester,  Pat Kane

Now to the Reality. In Don't Breathe the Moon Dust the Health effects pf Regolith are discussed. Evdently Mars Regolith is especially nasty.

Martian dust could be even worse. It's not only a mechanical irritant but also perhaps a chemical poison. Mars is red because its surface is largely composed of iron oxide (rust) and oxides of other minerals. Some scientists suspect that the dusty soil on Mars may be such a strong oxidizer that it burns any organic compound such as plastics, rubber or human skin as viciously as undiluted lye or laundry bleach.

"If you get Martian soil on your skin, it will leave burn marks," believes University of Colorado engineering professor Stein Sture,

One thing to think about is that most modern cities are thoroughly paved rarely do people walk on open ground, so why should we assume that we will have unprepared landing pads and drive and walk through lose regolith? Paving landing pads, roads and walk ways will reduce dust exposure tremendously.

Also using lava tubes for radiation protection instead of burying surface structures in regolith will also reduce exposure to dust significantly.

Another idea of what to do with the Moon dust is make it into solar panels.

Here's how local scientists propose to power the first human outpost on another world: Launch a rover to the moon and melt its dusty soil into acres of electricity-generating solar panels. A year later, when astronauts arrive, all they have to do is plug into the grid.

If this machince could caught the nitrogen, noble gases and water coming off the regolith it would be perfect.

Weathering Solar Storms on the Moon

In A Bad Week to be on the Moon By Tony Phillips describes the effect on the Moon of this weeks solar storm and the one in 1972. While solar flares are a hazard on the Moon they are definitely not insurmountable.

A lava tube would offer fine protection for a lunar base, 30 plus meters of rock should storm just about any thing the sun could throw at it.

For surface operations there have been electronic shields proposed. Also since the radiation would only penetrate 11 cm of water and LEM wall would have cut radiation exposure significantly maybe we should consider possible ways to build emergency shelters. One possibility is to assure that there is a solar flare warning system and all astronauts who can not return to base within 7 minutes are issued a plastic bag large enough to fit into and a shovel. Then the astronauts caught on the surface could lay out the plastic bag on the ground preferably in the shade of a large bolder and cover the bag with as much regolith as they can in 5 minutes and then get in. While this wouldn't be perfect a few inches of regolith could be the difference between a fatal dose and not.

Lunar Radiaiton Shields

A recent Space.com article entitled Lunar Shields: Radiation Protection for Moon-Based Astronauts, talks of NASA research into eletrostatic shielding for a lunar base. While I am for research into radiation shield intended for the lunar environment, the best shielding for a lunar base is a lava tube. 50 meters of rock will stop just about anything. Eletrostatic shielding might be great for use during a solar flare for those caught on the surface, but it is no good for stopping micrometeors so a lunar base will still require other physical shielding.

Sorry Boys you can't go to Mars

In That's one small disappointment for man, a giant trip for women
By Severin Carrell
19 December 2004

"A new study by experts in the United States has claimed that women may make better and fitter astronauts for long trips into space. Men are simply biologically inferior and less able to withstand the rigours of space flight."

I had heard of the lift mass to IQ Ratio being a reason to send only women to space but this is a new argument.

Landing pads, Life Support Volatiles and Rocket Fuel from Mining

Two problems that can be solved simultaneously are the need for prepared landing facilities and the need for life support volatiles. Since the Moon as very little atmosphere and has low gravity particles raised from the lunar surface when a lunar vehicle lands will effectively become projectiles and travel balistically for up to 2 km damaging metal and glass surfaces. Particles land on all surfaces and are difficult to remove. The only effective long-term solution is to solidify the particles in the landing area into a solid surface. The melting temperature of lunar regolith is above 1200 degrees Celsius that is the point at which all of the solar wind volatiles are released. If a circle 250 meters in radius and two meters deep were mined, the regolith melted and put back as tiles, all the volatiles needed for the initial lunar base would be released. This is according to the estimated concentration approximations of volatiles by L. A. Haskin of 100 g of hydrogen per m3, 100 g of nitrogen per m3, 200 g of carbon per m3, 26 g per m3 of noble gases. Multiply these amounts by roughly 390,000 m3 of melted regolith for the landing pad and there will be 39,000 kg hydrogen, 39,000 kg nitrogen, 78,000 kg carbon and 10,140 kg of noble gases. Oxygen is present in much greater quantities. This should be more than enough for the initial life support needs of a lunar base.

One of the challenges to the design of any mining equipment that heats the regolith will be sulfur content. Lunar regolith is high in sulfur. If sulfur combines with hydrogen it will form sulfuric acid which could damage the equipment. But this sulfur could be very important to the future of lunar development. This is because it could be used as rocket fuel combining Sulfur and Oxygen to provide propulsion. Presently most fuel mixtures for regular rockets require hydrogen and Oxygen. While oxygen is plentiful, hydrogen even with the ice on the poles is rare on the Moon. So it would be extremely beneficial to find a substitute for hydrogen, which is plentiful on the Moon. Although at this point it is theoretical and would be highly polluting in Earth atmosphere, it could allow a lunar base to be self-sufficient in rocket fuel. Sulfur oxygen rocket would not be polluting the moon since the sulfur is already present.

The Waste Water System for a Lunar Base

A wastewater system for a lunar base can be bigger, more complex and more like terrestrial systems then other space water treatment systems since it is on solid ground rather than moving. In designing wastewater treatment system for a lunar base, the differences from Earth must be kept in mind. On a lunar base the wastewater system is also the hydroponics fluid renewal system. The lower gravity means gravity separation will not work as well. But there are advantages; since the environment is controlled already, it can be set to the ideal conditions. On Earth aeration is done with air. On the Moon there is no air so pure oxygen from ilmenite mining could be used for aeration.

Wastewater will come from the showers, clothes washing, dish washing, food preparation, and toilets. Most will be wash water so; detergents should be biodegradable. There should be separate plumbing for toilets. Toilet waste is highly concentrated in complex molecules which will take longer to break down. Toilet waste is in pathogenic bacteria. These bacteria are not killed by traditional waste treatment. They tend to die slowly over time. There are ways the kill bacteria quickly but it requires energy. On the Moon, energy will be relatively cheap but carbon, nitrogen and hydrogen will be quite expensive, on Earth it is just the opposite. On the Moon human waste will be a valuable resource. In fact at present launch costs human waste is more valuable than gold.

The wastewater system described will use high technology, basic physics, plants and animals to clean the water. The equipment used in this system will include a wastewater storage tank, a pathogen inactivation chamber, algae grower, fish tanks, a clarifier, a high pressure aeration tank, duck weed troughs, gravity separator, zebra mussel tank, worm beds, ultra violet water sterilizer, and a super critical water oxidation (SCWO) unit. Most of the wastewater will flow into the storage tank, only the toilet waste will go elsewhere.

Toilet wastes will be sent to the pathogen inactivation chamber. According to the World Health Organization all pathogens can be inactivated in human solid waste if it is held at 70° C for 24 hours. The pathogen inactivation tank will turn human waste into a safe, nutrient rich resource for food production. The chamber will act as a gravity separator. When it comes time to drain the tanks the solids will have settled out. The liquid portion will be put into the algae grower while the solids will put into the fish tanks. Toilet wastewater will be used to grow algae to feed the fish. The algae will absorb ammonia and convert it into protein. The algae will help purify the water and will be a protein rich food for the fish.

The fish tanks will contain tilapia fish. Tilapia are used in sewage fed aquaculture as a source of cheap protein in developing countries. This is an excellent way to utilize human waste and to produce fresh fish to add variety to the diet. Fish can be grown in tanks filled with used hydroponics nutrient solution. The water from the fish tanks will go into the clarifier then be cycled through the algae grower again. The clarifier will separate some solids out.

Next water from the wastewater storage tank and from the clarifier will be put into the high efficiency aeration tank and aerated with pure oxygen for 2 hours in order to oxidize most of the organic compounds in the water. The aeration tank will use a kilogram of pure oxygen for each cubic meter of wastewater. Aeration with pure oxygen will reduce the amount of gas that must be pumped through the water and allow for less turbulence. Using pure oxygen in sealed tank aeration cuts the time from days to hours. The oxygen would come from the mining that will be occurring as part of lunar base operations.

After the aeration tank the wastewater will flow into the duckweed troughs. The duckweed will provide a home for the microorganisms which will help remove bacteria from the water. Solids will tend to settle on the bottom, which will give them a longer time to decompose. Next the water will flow into the gravity separator. Solids drained from the gravity separator will be put in the worm beds. Worms will be used to compost waste. Worms have been used for thousands of years to breakdown waste into nutrients useable to plants. Worm casting are excellent fertilizer. Sewage sludge can be used by worms at a rate of half a pound per square foot per day.
Next the water flows into the zebra mussel tanks. Since gravity separation will not be very efficient in low gravity and filtering membranes would require resupply from Earth, zebra mussels are a solution, in just a few short years they have managed to clarify all the water in several of the Great Lakes. They are very efficient, each one filtering up to a liter of water a day each. Within 6 hours they can remove 90% of the suspended solids in wastewater and deposit it on the bottom.

Finally, Ultraviolet (UV) light sterilization will kill any bacteria remaining in the water. The clean water will then go into tanks for hydroponics fluid.

If the water gets too contaminated system then it will be sent to the Super Critical Water Oxidization (SCWO) system. At about 400° C and 4000 PSI water becomes super critical solids drop out of solution and organic previously immiscible become miscible and can be easily oxidized. So, organic compounds are converted into carbon dioxide, water, salt and ammonia. This obviously will kill any biological contaminate.

The potable water for the base will come from the dehumifiers in the plant area. There will be several hundred grams of water for every grams of biomass produced. The roots are a barrier to impurities and pure water evaporates off the leaves. The water will need to be filtered and sterilized.

Maximizing Food Production while Minimizing Photosynthetic area on a Lunar base

Food production with higher plants is the best way to perform many of the life support processes like, carbon dioxide reduction, oxygen generation, and water purification. Photosynthetic area will be expensive off of Earth so this area needs to be as small as possible. The plants in the hydroponics system will be the base’s main water users. The plants drive the power system because fast growing plants require large amounts of light. They drive the dehumidification system because plants transpire hundreds of grams of water per gram of biomass produced. They drive the cooling system because of the heat generated by the lights. The plants drive the waste water system as the hydroponics will need to be flushed in order to control pathogen contamination and salt build up.

A wide variety of plants should be grown in the system to provide a varied diet. A varied diet is required for long term acceptance. The largest area would be devoted to high producing, carbohydrate rich staples, such as potatoes and wheat. The next largest area devoted to nutritious, versatile and highly producing crops such as soybeans, sweet potatoes, peanuts, rice and sugar beets. A smaller area used for fast growing vegetables and fruit such as lettuce, tomatoes, carrots, chard, cabbage, onion, strawberries, melons, etc. A few square meters total used for herbs and spices to give flavoring for the food like to garlic, mint, chamomile, dill, oregano, basil, sage, rosemary, and thyme. This way of dividing up the area should allow for a varied diet with customary staples, plentiful vegetables and fruit and spices for flavor. The exact mix of plants will be selected to provide a good diet and maximum useable biomass production. The diet should be designed by a botanist, nutritionist and a chef working together to plan a set of plants which are easy to grow, provide good nutrition and can be prepared in a variety of tasty recipes with ingredients grown locally.

Plants produce carbohydrates, protein and fats at different rates. Carbohydrates are most efficiently produced. Proteins are less efficient, while fats are slowly produced. It is very hard to get sufficient fat from fast growing plants. The plants should be the primary source of carbohydrates while animals living off waste products should be the primary source of protein and fats. By shifting the food production requirement for the plants from a balanced diet to a carbohydrate factory, the photosynthetic area required drops substantially. During the initial stages of lunar settlement it might be cost effective to ship up vegetable oil to supplement the food supply since oil is very dense in calories yet inefficient to produce. Just 22 kilograms of vegetable oil a year will supply all the fat required for one person and will provide 27% of the calories. While we should assume some fat will be produced by the plants if can ignore the fat requirement of the diet and assume supplements for vitamins and mineral then food production become much easier and requires much less photosynthetic area.

The diet on a lunar base is not necessarily vegetarian or vegan. Not all food will come from green plants some will come from animals and some from mushrooms. All plants produce some parts, which are inedible by humans. The animals will be needed to help recycle them and to provide food from resources that otherwise would be wasted. As meat production is inefficient the diet will only have limited quantities of meat. All meat will come from animals grown for other reasons. The animals will be a cow and some chickens feed on humanly inedible plant parts, and kitchen scraps. Mushrooms will also be grown on waste biomass and chicken manure. The cow could be feed stems, leaves and roots giving milk in return. Chickens could be feed on kitchen wastes giving eggs.

Milk and eggs will be provided from what would otherwise be waste. By doing this it will actually increase food available from a given photosynthetic area. These animals add milk, cheese, butter, eggs and occasionally chicken and beef to the menu for only a small addition of space and no increase in required plant production while helping recycle waste biomass. The animals will actually allow a decrease in photosynthetic area by turning inedible plant biomass into tasty calories. These will make protein and fat from what would be waste. The plants will produce most of the food but about 1/3 of the food can come from non-photosynthetic sources.

The humanly inedible plant parts are usually those, which are indigestible to humans because they contain too much cellulose. Unlike humans, cellulose is not a problem for cows. In fact they require cellulose to produce fat for the milk. Feeding the waste plant parts to the cow will produce milk and meat at the same time disposing of large amounts of waste. Although growing crops only to feed animals is an extremely inefficient way of producing of food. On the other hand using waste plant parts as cattle feed is extremely efficient. There will be 1 kilogram a day of humanly inedible biomass produced day. Much of this material will be cellulose, which will be hard to decompose. The digestive system of the cow will speed this process. If the plant parts are 50% water by mass than there will be 500 grams dry weight of food for the cows per person. Milk output of cows is 1.25 times feed input so 625 grams of milk will be added to the food supply. This is over a pint per person. This is more than most people want to use on a daily basis. The excess will be used to produce cheese. Butter will be produced from the cream skimmed from the milk. These will provide 20% of the fat and protein in the diet. Cows allow for a more varied diet by providing milk, butter, cream, cheese, yogurt and occasionally meat.

Chickens are able to turn waste into eggs and meat. While cows live on a high fiber, low protein diet. Chickens need a low fiber, high protein diet. So chickens and cows are complementary. Chickens can be fed on table scraps and food processing waste, slaughter waste, eggshells and feather meal. Chickens will produce eggs as well as break down waste into a form, which is closer to what the plants can utilize. Chicken Manure is also good for growing mushrooms on when mixed with straw.

Mushrooms are an excellent food source for a lunar base because they require no light, require little space and grow on waste biomass and manure. They are an excellent source protein. Four to five lbs. of mushrooms per square foot is possible.

Lunar Lava Tubes

Humans on the Moon would be protected from solar and cosmic radiation by building habitats inside lunar lava tubes. Radiation shielding will need to be at least three meters thick to protect residents from cosmic radiation and solar flares. That is why an intact lunar lava tube is an ideal place to build the first lunar base. They are naturally occurring self-supporting radiation shields that have roofs which are tens of meters thick. Lunar lava tubes are much larger than those on Earth and are large enough to accommodate a large base. They are hundreds of meters wide. They can be thousands of meters long. A base in a lava tube could be easily expanded. An intact lunar lava tube will provide ideal protection from meteors, radiation, extreme temperature fluctuations and the abrasive lunar dust. It is also possible that the lava tubes will contain life support volatiles since they are a stable -20 degrees Celsius (Mendel) any water vapor which entered the tube would freeze and still be there. Intact lava tubes could be found near riles on the border between mare and highland. Partially collapsed lava tubes can be seen in photos of the Moon. They have been considered for use as a location for a lunar base by Coombs and Hawke. These lava tubes have questionable structural integrity because they are partially collapsed. It would be much better to find an intact lava tube. They will be larger since they are whole. They are probably deeper. Also in the future an entire tube could be sealed air tight so there could be earth-like sub-selene cities.

The only problem with using an intact lava tube is finding them. Two possible ways of finding lava tubes are radar or active seismic sounding. There are problems with both. Radar may not work. Seismic sounding only covers a small area a time. Radar on Earth only penetrates about 10 meters because the Earth is very wet. The Moon is extremely dry but other things, such as metals which, may not allow radar to penetrate the 1 kilometer needed for a complete survey for lava tubes. Even if radar does penetrate, large satellites may be required.

Seismic sounding will only cover a few square kilometers at a time. This would mean we would have to have a good idea where to look. Areas with partially collapsed lava tubes and areas with similar geology are a way to narrow the search. The area could also be narrowed by doing a very accurate gravity survey of the Moon. Areas which have too little mass could be areas with lava tubes. One complication with doing an active seismic survey of the Moon is that the dry lunar rock and regolith do not attenuate seismic waves. The Moon rings like a bell when it is impacted. There is no water to absorb the sound vibrations. When the Apollo 12 Lunar Module was crashed into the Moon, the Moon reverberated for over two hours. This means we can not simply use terrestrial analysis techniques on lunar seismic data. Some one will have to develop new techniques.
Both radar and active seismic survey were done as part of the Apollo program. These experiments only obtained small amounts of data. Also the equipments used were primitive by today’s standards. All of the Apollo experiments were designed with limited understanding of the lunar environment. The radar experiments where hindered by the limited data storage technology. This should not be a problem with modern computer equipment. The seismic experiment data had larger error bars then the magnitude of the data. More data and better designed experiments should solve this problem. The experience of Apollo and the technology developed since then along with experiments in the future will give us everything we need to find intact lunar lava tubes.

Once lunar lava tubes are found to use them all we would need to do is to drill an elevator shaft. Then floor of the lava tube will need to be cleared of debris and leveled. A dust-lock could be used to allow a cleaning area for equipment and space suits before entering the base. The ends of the base area could be sealed by stretching the same material used for the inflatable habitats over the opening sealing the section of the tube air tight, it would be a buffer between the lunar vacuum and the high internal pressure of the base. This would reduce the rate of air leakage from the habitat. Once prepared, the tube will be ready to receive inflatable structures.