Revision as of 21:33, 14 November 2012

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• NOT-YET-PLAYABLE pre alpha, just tech experiments so far
• http://ghoulsblade.schattenkind.net/webspacesim/
• realistic simulation of landing and constructions on the moon using remote controlled rovers/robots and chemically processing on-site material

details

• a little hobby project worked on irregularly
• tech: playable in browser without plugins, using webgl and javascript
• aims for realism, using current technology and prices as far as possible.
  • current data (prices,weight,chemical composition,...) is just preliminary for getting the simulation mechanics running and will need intensive fact-checking and research later
  • optional experiments with theoretical launch & propulsion systems only as long as they are scientifically realistic in the near future
• In-situ resource utilization by chemically processing Lunar Regolith to extract chemicals and process them to manufacture Solar Cells, Propellants, Structures and other things
  • construct more/bigger machines by combining components imported from earth with cruder parts made from in-situ chemicals (using Additive Manufacturing / 3D Printing)
• experiments with plant-growing e.g. Hydroponics (light, temperature, and nutrients from chemicals)
• later experiments with other planets, moons, asteroids, satellites,probes,landers and in space construction, and transporting material between multiple sites.
• Maneuvers using Orbital Mechanics like Gravitational Slingshot and Atmospheric Drag to conserve fuel

• 2012-09-29 separated into own project, was originally space-test inside mountainfort experiment

outline of simulation/gameplay

• one "free" launch to moon for around 300mio$ (incurs dept)
• build/make solar cells + fuel + electro-magnetic launch system on moon
• bring fuel to earth orbit for trade (pay back initial dept and trade for equipment and material to expand further)
• access and harvest materials from near-earth-asteroids
• in-space construction of stations and ships
• possible goals/achievements :
  • pay off initial dept
  • fuel & iron/aluminium depot in earth orbit, trade certain amount
  • harvest materials from an asteroid and return them to earth orbit or lunar base
  • exploration missions to send 10kg,100kg,1t,10t orbiters/landers/rovers and sample-return-missions to different planets, moons, asteroids...
  • construct underground mining facilities on the moon to access single-mineral deposits that don't require costly separation
  • move + capture asteroid of certain minimum size in earth orbit (in-situ fuel production + time) for further processing
  • construct Hydroponics facility to grow vegetables on moon or in orbit
  • construct space station in low-earth orbit (low radiation) to sustain 100 humans for 1 year
  • construct moon base to sustain 1000 humans for 1 year (underground : low radiation)
  • in space construction of a ship capable of carrying and sustaining 1000 humans for several months, including mass needed for radiation shielding
  • make self-sustaining (not reliant on earth-launches) colony for x thousand humans on moon/mars/earth-orbit

rationale

• no time pressure, remote-controlled robotic rover doesn't need food or air, solar cells last several years, so even inefficient manufacturing machines will fullfil their tasks eventually
• due to vacuum (no air friction) and much lower gravity than earth, an electromagnetic launch systems should be feasible (if in doubt add rocket-assisted)
• welding in vacuum was already successfully demonstrated on the ISS, and a robotic rover with 2+ arms should be able to fixate metal components and move a welder
• smaller rough components can be produced using 3d-printing technology

• aluminium powder as well as hydrogen from the water-ice discovered in recent years can be produced as fuel with oxygen (plentyful since major moon minerals are oxides)
• silicon and aluminium from regolith can be used as basis to create solar cells, at least in combination with further materials/components imported from earth
  • by now it is already possible to print solar cells on paper
  • it should be technically feasible to manufacture at least inefficient solar-cells on the moon using locally produced aluminium, silicon, and further componets imported from earth.
  • unlike on earth, where roof-area is very limited and costly, high energy_per_area is not required.
  • advances in thin-foil solar cells allow for high energy-per-kilogram efficiencies (more than 1kW/kg)
  • according to wikipedia a falcon 9 heavy can launch above 50 tonnes into low earth orbit for 80-125 mio $ so a large amount of solarcells could be brought initially to jumpstart local production.
• vaccum allows using thin aluminium foil without oxidation. this allows large scale mirror-arrays to increase solar cell efficiency, or to produce heat directly
  • low gravity and no wind mean lower stress on supporting structures
• aluminum and iron for structures can be produced from regolith
• due to high launch cost from earth, bringing fuel and iron/aluminium for structures from moon should be interesting economically, and at least allow trade for components that can only be manufactured on earth
• human inhabitation requires at least heating, oxygen, water, food and waste reprocessing
  • for food production hydroponically grown plants are interesting, besides oxygen and water, those require mainly carbon and nitrogen? which have to be imported from earth or asteroids.
  • partial reusage from waste-reprocessing should be possible

lunar regolith (moon-stone)

estimated average mineral composition on surface

• 42% Si O2 (silicon-oxide) 30.6 MJ / kg
• 14% Al2 O3 (aluminium-oxide) 30.9 MJ / kg
• 16% Fe O (iron-oxide) 4.9 MJ / kg
• 12% Ca O (calcium-oxide) 15.8 MJ / kg
• 8% Mg O (magnesium-oxide) 24.7 MJ / kg
• 8% Ti O2 (titanium-oxide) 19.7 MJ / kg

elements by weight

• 42% oxygen (fuel,...)
• 20% silicon (solar cells)
• 12% iron (structures,conductors)
• 7% aluminium (structures,conductors,solar cells,mirrors,fuel)
• 9% calcium (better conductor than copper by weight, reactive with air, but no problem in vacuum)
• 5% magnesium
• 5% titanium (structures?)

energy for smelting etc

The MJ/kg noted next to the minerals are the chemical energy required to react 1kg of metal from the mineral. (at standard pressure and room temperature, mind)
In practice i'd estimate around 30% efficiency or less so 3 times as much energy would be required. (reliable numbers seem to be hard to come by, help appreciated)

Using Thin-Foil-Solar-Cells to optimise energy-per-kilogram rather than energy-per-area, estimates are 1-2 kW/kg due for space trial in 2013. Less tech-ready theories even state 5-6kW/kg.

Later, using thin aluminium mirrors to concentrate sunlight onto the solar cells it should be possible to increase the generated energy significantly.

1kW = 3.6 MJ/h , so with 30% efficiency, 30 kg of 1kW/kg solar cells would be sufficient to produce 1kg of aluminium & silicon per hour. Or 6kg iron.

Before smelting, the minerals composing lunar regolith will likely have to be separated before smelting, which will likely require significant energy and some chemicals (acids/bases) that cannot be 100% recovered. (more infos&numbers needed)

Silicon produced like this needs to be purified before being usable to manufacture solar cells, this requires repeated heating, and thus significant energy.

Focusing sunlight via large mirror-arrays to generate heat might be interesting in the later stages. This could even be interesting for electricity production via turbines rather than photovoltaic. (existing earth based projects in desert)

Note: generating electricity via heat might be more efficient on the moon than on earth due to low ambient temperature (so high delta) in crater-shadows (?iron with black coating as heatsink, since regolith likely has bad thermal conductivity) 1 2 3

radiation, micro-gravity, dust

Humans are vulnerable to radiation (high-energy protons emitted by solar flares and galactic cosmic rays) and health problems caused by long-term exposure to micro-gravity.

The micro-gravity can be solved by rotating habitats (centrifugal/petal force).

While electrically charged radiation can be shielded magnetically, the only known thing that helps against neutron radiation is a lot of as-dense-as-possible or hydrogen-rich mass.
Lead is likely rare (asteroids?), so lots of regolith (cheap) or possibly water/ice (double as fuel+drink) are interesting alternatives.
For the moon, constructing the habitats underground seems sensible, and is also beneficial for heating.

Lunar dust is a health-hazard for humans, sticks to surfaces like mirrors and solar cells due to charge, darkens surfaces (heat by sun), and is a danger to machines with moving parts.

misc

• LEO = Low Earth Orbit : low radiation thanks to earth's magnetic field (stations like ISS)
• solar energy reduced by square of distance by sun : moon good & mars still ok, but mars already has 50% of earth/moon, jupiter and beyond less than 4% of earth/moon solar energy for the same area
• water ice on moon,mars,Europa(Jupiter),Titan(Saturn),Saturn-Rings,Enceladus(Saturn),Comets
• Asteroidmining: Near-earth-asteroids as source for fuel (low grav : easier than moon) or chemicals rare on moon (carbon, nitrogen, copper, water-ice ...)
  • "In terms of delta-v and propellant requirements, NEOs are more easily accessible than the Moon." (wiki-quote)
• Asteroid belt between Mars and Jupiter : mainly carbon(75%),fe/mg-silicate(17%),metallic(nickel-iron)
• Meteorites: mainly Chondrite=Olivine((Mg, Fe)2SiO4)+Pyroxene(XY(Si,Al)2O6) and Achondrite(basalts or plutonic rock)
• mining/digging/drilling on lunar problematic due to high friction of strongly compacted material, and low gravity
• Interplanetary transport network gravitation wells and Lagrange points for conserving fuel, but slower than direct Hohmann trajectories
• electro-magnetic launch from moon (mass driver). maybe also to slow down material landing (near-horizontal approach, similar to mag-lev trains)
• Aerobraking and Lithobraking (=shallow angle impact)
• Specific impulse and propulsion methods with tech-readyness level and impulse/thrust infos