Module design

1. Module design • Titanium rounded cube 15m x 15m x 15m • To be added to the Alaskol lunar lava tube settlement under the Shackleton crater • Almost entirely self sufficient - • Cycles it’s own atmosphere and has its own food supply, only requires supplementary food such as in vitro meat, and electricity, from the main base • Absolutely safe from radiation and micrometeorites • Pressurised to 90kPa to reduce unnecessary strain on the structure Plant and life support systems room The exact arrangement of rooms in the module can be chosen before fabrication Pressurised walkway to the main base

2. Construction details • Shiny titanium foil will also be produced by rolling the metal. • This serves as Multi Layer Insulation like on satellites to reduce heat loss via thermal radiation: Conduction and Convection are already zero due to the presence of a vacuum outside. • Each layer of foil reflects most of the infra red reaching it back into the module. Most of whatever it absorbs will be re-radiated and reflected by the next layer. • All of the following to take place further down the lava tube: • Titanium is to be extracted from abundant ilmenite (FeTiO3) as follows: • 2 FeTiO3 + 7 Cl2 + 6 C → 2 TiCl4 + 2 FeCl3 + 6 CO • TiCl4 + 2Mg → Ti + 2 MgCl2 • The resulting sponge of titanium will be washed of MgCl2 and melted by an electric arc furnace into pre-dug “regolith casting moulds” using the same principles as sand casting on Earth, to give 60m x 15m x 5cm blocks and twice as many 15m x 15m x 5cm blocks, all with curved edges. • These are to be laser welded into a cube shape with curved corners and sides, giving strength almost equal to the unwelded metal itself. Exploded section through wall Lunar fibreglass coating 5cm titanium Titanium foil • As pure titanium has Young’s, shear, and bulk moduli to the order of tens and hundreds of gigapascals, and titanium hulled submarines on Earth can dive to 1000m (100atm) with ease, the structure will withstand a slightly reduced atmospheric pressure of 90kPa with no problems. The chlorine and carbon required in the process would have to be stringently recycled, as they are rare on the lunar surface

3. Radiation and Temperature Control • Regolith blocks as much radiation as aluminium. • 0.7-1.0% reduction per unit areal density (g cm -2 ) for 400MeV beta • 20000 cm * 1.9g/cm3 = 38,000 g/cm2 • Using 0.7%: (0.993)^38,000 = 10-200% of the radiation penetrates, so background radiation inside the lava tube is less than that on Earth. Lift to and from surface 200m Lava Tube 200m of regolith Surface • Surface temperature varies from -153 to 107 oC • As shown, the module design is almost perfectly insulated, so maintaining a comfortable 22 oC is not a problem • Radiative heat exchangers keep temperature comfortable. 150m Location of modules marked in red • Total protection from micrometeorites

4. Plant-based life support system • Supplied with artificial light in a hydroponic system, in situ plants solve the problems of CO2removal and O2production, while also substantially increasing the food supply. Most food still supplied by base. • As per the maths below-right, 230 plants will sustain four adults, plus twenty to remove CO2produced by respiration. As two people will be children, this gives a large safety margin. • Plants genetically modified to produce more fruit and photosynthesize more (meaning more gas exchange) will be used, and via codon re-engineering they are unable to be infected by viruses. • Autonomously looked after in a plant biome incorporating a robot arm with soft grip technology controlled by a tiny microprocessor linked to sensors to detect height and colour to infer health and location in life cycle, harvesting and replanting fruit and seeds when necessary. • Essential nutrients (nitrates, phosphates, potassium compounds) are present in trace amounts in lunar regolith and are concentrated in bulk by the main settlement then autonomously distributed to the modules via an internal small item delivery system akin to a pneumatic tube but utilising linear magnetic induction, like a maglev train. Per hour, the average person breathes in 53L of O2, with 500mL of air per breath. 252L of air are inhaled each hour, with 12 breaths / minute. (21% of 252 = 53) The average plant leaf produces 5mL of O2 / hour. With solar powered lighting providing light of optimum wavelength (400 – 700 nm – blue and red wavelengths), sufficient water, waste CO2 (from the settlement), and the use of genetically modified plants, the conversion rate will increase to 30mL of O2 / hour / leaf. Each plant has 30 leaves  30 x 30 = 900mL O2 / hour / plant. For four people  (53000 x 4) / 900 ≈ 230 plants needed to support 4 people. 50000 plants take up one hectare, so 0.005 hectares are needed =~ 50m2 of lunar land needed, in a ten tier system of sliding drawers only a 5m x 1m section of base needed. 10 tiers of hydroponic drawers require only 5m x 1m of floor space

5. Water and Nutrient cycling Sink Shower Urine • A system similar to the ISS ECLSS will be used, but less complicated due to the presence of gravity. • Water coming out of this system is absolutely safe to drink, even though it started largely as urine • As no system can be 100% energy or material efficient, it is necessary for the main base to supplement the water supply by microwaving lunar regolith and condensing the resultant vapours. • Other chemicals used in the process, such as H2SO4 • Solid waste contains too high a proportion of salts and would be inefficient to process for water, instead inorganic minerals and other nutrients are used to fertilise the hydroponically grown plants, while any excess of the remaining dry sludge would have to be disposed of in a crater by the main base. “Used” Fluid Cr2O3 and H2SO4 added Not pure enough Low Pressure Distillation Fumes, volatiles and organics out 3 stage filtration beds Particulates out Low Mr organics out High temperature catalysis Pure enough Electrical conductivity probe International Space Station Environmental Control and Life Support System Storage

6. Long term effects of 1/6g • Just as muscle and bone wastes away with reduced physical activity on Earth, the reduced gravity (1/6 of Earth’s) on the moon causes physiological changes as shown on the left. • Cells called osteoblasts produce new bone tissue when the level of daily mechanical loading exceeds normal physiological levels, and cells called osteoclasts remove existing bone tissue when daily mechanical loading falls below normal levels. A similar process occurs in the muscles. • “Moonlings” will spend their entire life in 1/6 g and be perfectly accustomed to lunar gravity. • The data above is extrapolated from data on the long term effects of 0g, (assuming a linear relationship from 0 to 1g) as to date there is no direct data on the long term effects of lunar gravity To accommodate the necessity of any inhabitants needing to make a journey to Earth, a part of the main base is a large lightweight rotating disc spun by a high torque electric motor which simulates a 1g environment. It is of radius 60m so using the equation below, will rotate at 3.86rpm to simulate 1g, and is only spun when an inhabitant is soon to make an Earth-bound journey so reduce energy usage. Making every module do this constantly would be a huge and unnecessary drain of energy Centrifugal chamber concept