ISRU Technology Modeling

1. ISRU Technology Modeling Brad Blair, Javier Díaz, Begoña Ruiz, Mike Duke Center for Commercial Applications of Combustion in Space Colorado School of Mines <bblair@mines.edu> Space Resource Roundtable November 3, 2004 Space Resources Roundtable VI

2. Outline • ISRU Technology Intro • Trade Space • Mining, Ore Hauling, Processing • Economic Model for Technology Investment Space Resources Roundtable VI

3. ISRU Technology Overview Exploration Technology • Satellite instruments for polar ice detection (remote sensing) • Surface robotic technology for resource delineation (grid drilling) • Subsurface sensing instruments • Surface mobility platforms (rovers) Mining Technology • Excavation and haulage systems to mine lunar regolith Beneficiation Technology • Ore handling and mineral separation systems for ice and regolith Processing Technology • Water extraction, electrolysis and H2 storage • Oxygen extraction • CH4/CO2 extraction, storage and upgrade to storable propellant • Gas separation and purification Supporting Technologies • Automation & robotics, surface support systems, fluid couplings, propellant storage & transfer, communication, navigation,power, etc. Space Resources Roundtable VI

4. Primary Technology Issues • Environmental Conditions • The lunar poles are characterized as an ‘extreme environment’ • Temperatures within the permanent shadow could be as low as 40 Kelvin; Dust adhesion is likely; Vacuum is extreme; Power will be limited; Electrostatic charging could be problematic; Mass will be constrained • The lunar equatorial regions are similar but not as cold, and daytime solar energy is available • System survivability is a key issue • Technical Challenges • Low temperature (40-70K) materials • Dry drilling, cuttings transport, and sample retrieval • Wear-resistant components and bearings • Automation and teleoperation (minimizing communication needs) • Fault diagnostics and fault-tolerance • System reliability, maintenance and repair • Miniaturized geosensing instruments • Modular serviceable systems, maximizing commonality Space Resources Roundtable VI

5. Mining Architecture & Technology FY03 Lunar propellant architecture inputs and outputs –CSM/CCACS FY04 Lunar technology model inputs and outputs –CSM/CCACS Space Resources Roundtable VI

6. Hauling Architecture & Technology • Shown just below are input assumptions and outputs of haulage system sizing estimates for ISRU integrated model • Also shown at bottom are technology factors related to hauling systems • These results are preliminary, an attempt to rationalize both data sets has not been undertaken at this point in time FY03 Lunar propellant architecture inputs and outputs –CSM/CCACS FY04 Lunar technology model inputs and outputs –CSM/CCACS Space Resources Roundtable VI

7. Processing Architecture 1/2 FY03 Lunar propellant architecture inputs and outputs –CSM/CCACS Space Resources Roundtable VI

8. Processing Architecture 2/2 • Note: The processing model described below assumes that polar hydrogen is in the form of water ice – an unproven assumption for now • Other processing system models exist for production of H2 production, O2 production and CH4 production • The water ice production model has the lowest projected system mass FY03 Lunar propellant architecture inputs and outputs –CSM/CCACS Space Resources Roundtable VI

9. Processing Technology FY04 Lunar technology model inputs and outputs –CSM/CCACS Space Resources Roundtable VI

10. Alternative Processing Technologies • Closed chamber, batch or continuous thermal processes • Generally understood and used industrially (e.g. fluidized bed reactors) • Requires technology for material inputs and outputs • May be limited in heating rate by thermal conductivity of lunar regolith • Microwave heating • Microwaves couple well with iron-rich microscopic coatings on regolith grains • Low residence times for fixed bed reactors may be possible • Microwave heating may be less efficient; full system tradeoffs are needed • ‘Cold’ plasma processing • Primary Benefit: Hydrogen radical is more reactive than molecular hydrogen • Lunar experiments by Lynch (1992 – chlorine/nitrogen) and Blacic/Currier (1999 - hydrogen/argon) • Extensive process experience in semiconductor industry • Reactant gases: Chlorine, Hydrogen (hydrogen is better) • A wide variety of oxides can be reduced • Lower overall reactor temperature than thermally-activated hydrogen reduction • Note: Reaction kinetics are currently unknown Space Resources Roundtable VI

11. ISRU Technology Trade Space Lunar Propellant Production System Mining & Excavation Beneficiation Heating bucketwheel electrostatic pumping loader/shovel electrostatic magnetic screening electrical resistance solar concentrator power supply excess heat Hauling microwave Processing polar equatorial conveyor pneumatic orecart batch retort fluidized bed spouted bed hydrogen plasma Integrated mining and processing machine? condensation, electrolysis, storage and distribution… Space Resources Roundtable VI

12. Criticality v. Optimality • Optimal solution • Goal: Maximize productivity • Problem: Schedule delays, programmatic acceptance, cost of iterative engineering/development loop, cost of exploration • Feasible solution • Goal: A demonstrated functional system • Problem: May not be the ‘best’ solution • Criticality • Which is more valuable today: A demonstration of ISRU feasibility or optimality? • What is the minimum solution set that is required for successful demonstration of ISRU on the Moon (i.e., is your proposed technology really critical to mission success?) • Decision Criteria • The cost/schedule optimal solution may look very different than the technically optimal solution Space Resources Roundtable VI

13. Technology Investment Modeling • Methodology • Start with an integrated architectural/cost model • Vary the technology assumptions • Keep track of the change in costs • The economic benefit of a proposed improvement in technical performance can be directly linked with an architecture and its scale • The present value of the technical improvement defines the maximum benefit of the technology investment • Technical performance criteria and schedule are additional results of this approach Space Resources Roundtable VI