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November 01, 2010

Space Manufacturing conference - Session 5: Engineering Materials from Non-Terrestrial Resources

Session 5: Engineering Materials from Non-Terrestrial Resources covered by Hobbyspace and Parabolic Arc

Electrical Energy Storage Using Only Lunar Materials
Dr. Peter J. Schubert, Packer Engineering Inc.

– Resources available on the moon for in-situ battery fabrication
– Can make batteries from in-situ materials by robots before humans land
- Storage requirements for a 2 person base - 1.2kW average, 1000 sq. meters, equatorial location, horticulture 100 W per sq meter for 20 sq. meters per person
- Obtaining Iron and Nickel from the moon



- Magnetically harvest fines
- Crack off silicates - centrifugal grinder
- Mond process selects out Ni; higher temp for Fe
- Or use a plasma method
- Potassium extraction
- K is in lunar atmosphere so we know it is volatile
- Vacuum roasting between 900-1200C
- Alternate is isotope extraction, separate by solubility
- Water abundant at poles only
- Vessels from cast basalt, dolomite, or polymer-lined vessels
- Specific power = 0.04 kWh/kg
- Leakage rate = 30%/month
- Deep cycling limit = 65%
- 0.5 mT/battery
- SImple dumb robots to make these before people arrive
- 6 batteries for 2-man base
- Water harvesting assumed
- Iron extraction - 16 to 55 batteries per year depending on method used
- Conclusion: Electrical storage possible with local materials

In-Situ Production of Construction Materials by Combustion of Regolith/Aluminum and Regolith/Magnesium Mixtures
Prof. Evgeny Shafirovich, University of Texas at El Paso

– can produce landing pads, rad shielding, thermal wadis by using in situ regolith
- Use sintering and other high Temperature methods
- Self-propagating high-T synthesis (SHS) - aka combustion synthesis
- Combustion of regolith mixtures
- pyrotechnic mixture e.g. Ti + 2B or metal powder Al or Mg
- Ignite electrically. Self-sustained propagation of combustion wave.
- Advantage - small energy consumption
- Previous studies at Univ. of Houston (Martirosyan & Luss) looked at Ii + 2B -> TiB2
- Successful test
- Faierson et al at VT demonstrated combustibility of regolith/Al mixtures
- Construction elements: bricks, tiles, ceramic layer on lunar surface for landing/launching pads and thermal wadis
- Comparative analysis of different additives to regolith with goal of minimizing additive
- effect of mixture density on combustion, effects of vacuum and gravity.
- Qualitative agreement with experiments at Virginia Tech for various mixtures
- Effect of milling on particle size of JSC-1A lunar simulant
- Shows videos of combustion expts with Regolith/Mg mixture - stead vs pulsating combustion.
- see combustion wave moving down column
- Conclusions: at the same wt%, Mg additive provides higher T than Al
- Much larger amts of ti + 2B mixture required for combustion
- Expt demonstrations of regolith/Mg mixture combustion
- Will look at regolith with smaller particle size of JSC-1A
- Study combustion of disks
- Study combustion products

Jerome Pearson, John Oldson and Dr. Eugene Levin, Star Technology and Research, Inc., Joseph Carroll, Tether Applications, Inc.
Electro Dynamic Debris Eliminator (EDDE) Opens LEO for Aluminum Recovery and Reuse
– ISS has mostly dodged hubcaps in terms of debris
– The problem is not the hubcaps but rather the 50 bullets it dodges for every hubcap
– More than 2,100 tons of debris in LEO — many of them are spent upper stages
– Biggest issue – 72 percent of the mass is Russian
– “The heroes here are going to be the lawyers”
– Russian stages are mostly aluminum tanks with magnesium
– Fork in the road — do we collect the stages and reuse them — or do we get rid of them
– 1,000 tons of mostly aluminum in old stages

- Build structures far larger than feasible with heavy-lifters
- Process & products:
- Collection only - use for ballast for slings
- Cutting up - create shingles for shielding, ventilates remaining structure to ease reentry burnup
- Metal bending and fastening - debris & radiation shields for any shape desired
- Melt-processing - enclose and melt shingles; do vapor deposition or molten spray inside thin balloons.
- allows better metal properties that with ingot processing
- Surplus Al alloys might be used as rocket fuel
- Debris processing market
- would cost ~$10B to launch 1000 tons to LEO
- With that amount of material could build a structure with same volume size of Air & Space Museum
- Describes EDDE vehicle
- See www.star-tech-inc.com/papers/EDDE_for_Debris_Conference.pdf
- Makes sense only if used repeatedly
- Add rendezvous capability
- Spinning capture net
- Al stages de-spin themselves in earths magnetic field
- Collecting upper stages
- Sweeper scenario
- Learning to handle processing of LEO debris before trying to process extraterrestrial materials


Dr. Paul Hintze, NASA Kennedy Space Center
Building a Vertical Take Off and Landing Pad Using In Situ Materials

– Landings and launches from moon kicks up dust, erodes surfaces
– Lunar dust and regolith are very coarse, abrasive
– Apollo 12 brought back the Surveyor 3 camera – found that lunar material had sand blasted the vehicle
– Need dust free areas for habitation and science

Polymer Palliatives
– spray polymers on it, spray it with water — helps to stabilize materials
– don’t need a lot of heat to cure — commercially available products
– disadvantages — mass, consumable and vacuum sensitive
– researching ways to spray polymers on the moon and to limit the mass involved

Sintering or Melting
–Sintering is a method of making solid objects from a powder by heating up the material until its particles adhere to each other
– Particle size, density and packing of regolith are ideal for sintering
– Microwave sintering can be used
– Use in-situ resources
– One or all phases can melt
– Depending on cooling rate, recrystallization will occur (material will be quite strong and not fragile like glass)

Solar Concentrator:
– Benefits: Uses solar power, lightweight and inexpensive
– Drawbacks: direct heating only heats the surface, uneven heating, and must follow the sun

Q&A
- Major problem getting electrodynamic tethers seriously
- Microwave sintering surface while adding dust to build up layer - tests look promising
- Clean up debris in LEO first with electo-dyn tethers and worry then about higher altitudes.

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