SPORE Project outline

Version 1.04    September 26, 2018

SPORE Project Outline

Lunar Surface Mining Challenges

SPORE at a Glance

Shielded Pressurized Oxygen Resource Extraction (SPORE) Overview

 

Phase One – Define all the components of the Shielded Pressurized Oxygen Resource Extraction concept

The first step is to figure out all the pieces needed to make SPORE work:

  • Relevant Lunar geology (selenology)
    • Apollo 12 site regolith characterization
      • Density – The density of the Lunar regolith increases with depth.
        • Relative density is 62% at the surface to 95% at 60 cm. We have no density data for regolith below 60 cm.
        • Bulk density is 1.45 g/cm3 at the surface to 1.74 g/cm3 at 60 cm. Average bulk density for the top 60 cm is 1.66±0.05 g/cm3. We have no density data for regolith below 60 cm.
        • Bulk density is erratic for regolith below 70 cm.
        • Overall, the density of the Lunar regolith is highly variable.
      • Physical composition
        • Particle size and frequency
          • Half the regolith (by weight) is 130 µm diameter or less at the surface. Regolith at the surface is classified as well-graded/poorly sorted silty sand to sandy silt (SW-SM to ML).
          • Particle sizes increase with depth and is more variable with increasing depth
      • Porosity and void ratio
        • The average, best estimate of in situ Lunar regolith porosity (n) is about 46% for the first 60 cm with a void ratio (e) of 0.87. The range is 42% to 54% and 0.71 to 1.14.
        • Well graded sands, gravelly sands, with little or no fines (SW) = 22% to 42% with a void ratio of .29 to 0.74.
        • Silty sands (SM) = 25% to 49% with a void ratio of .33 to .98.
        • Inorganic silts, silty or clayey fine sands, with slight plasticity (ML) = 21% to 56% with a void ratio of .26 to 1.28.
        • The porosity and void ratio of the mining site will vary depending on depth and location. Our Homesteaders might hit a pocket with a very high void ratio. Or they might have to remove a large rock, creating a large void. SPORE must be able to handle fast changing and unpredictable conditions.
      • Permeability
      •  Diffusivity
        • Larger particle sizes and greater soil porosity increase gas diffusion.
        • No direct experiments have been run on Lunar samples.
      • Chemical composition
        • Not necessary for the initial experiments. Plus, it’s highly variable.
    • Apollo 12 site mega-regolith characterization
      • Density
        • Unknown – Core samples did not reach the mega-regolith.
      • Physical composition
        • Particle size and frequency
          • Unknown – Core samples did not reach the mega-regolith.
      • Chemical composition
        • Unknown – Core samples did not reach the mega-regolith.
        • It is assumed to consist mostly of breccia from local bedrock and ejecta from impact sites.
    • Acceptable simulants
      • I’m not sure regolith simulants really matter for the SPORE project. The regolith is so unpredictably variable that two different samples will probably have significantly different properties. SPORE needs to be flexible enough to handle all the varieties of regolith our Homesteaders will encounter, not tailored to deal with just a few of the possibilities.
      • Available simulants are expensive and can’t simulate all the parameters of real Lunar regolith anyway.
      • Starting out I’ll just use sand and gravel to approximate the needed densities, particle size distribution, and porosity.
  • SPORE physical components
    • Shield wall
      • Materials
      • Designs
      • Construction tools
    • Regolith blanket
    • Temporary regolith pressure barrier (to mitigate atmosphere loss)
    • Excavation tools
    • Material transportation tools
  • SPORE techniques
    • Regolith excavation techniques
      • Dust control
      • Oxygen atmosphere pressure loss mitigation
    • Mega-regolith excavation techniques
      • Dust control
      • Oxygen atmosphere pressure loss mitigation
    • Material transportation to processing machinery
    • Shield wall construction
      • Optimal 100% oxygen atmospheric pressure
    • Iron pressure hull habitat construction
      • How are we going to build the pressure hull while still allowing access to more excavation?
  • Existing research done on similar concepts

 

Phase Two – Experiments

 

Phase Three – Working (non-flight ready) scale prototype of a SPORE structure
  • The goal is to have a prototype “on the shelf”. I won’t know all the steps necessary until I am further along.

 

Phase Four – Public outreach and education
  • Scale non-functioning mockup
  • Publish data and findings
  • Book – written for non-scientists

 

Check out the Support LH page if you find this project as exciting as I do!

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