Electrical Nuclear Systems of the Mars Homestead Project

Electrical & Nuclear Systems of the Mars Homestead Project Joseph E. Palaia, IV Programming Team Member Mars Foundation - Mars Homestead Project jpalaia@mit. edu How Future Martians Will Have Fun

Scope of Mars Homestead Project Programming Effort • First permanent settlement on Mars • Sized for 12 people, with straightforward expansion capability • Built largely from local materials (water, regolith, atmosphere) • High level of self-sufficiency, esp. for high-mass, low-tech items. • Industrial capabilities enable settlement of the frontier, improve sustainability & safety. Program Managers Mark Homnick – HVAC, Brick Manufacturing, Ore Beneficiation Bruce Mackenzie - Architectural & Other Technical Concepts April Andreas – Mars Cookbook James Burk – Webmaster Frank Crossman – Polymers Production & Glass Manufacturing Robert Dyck – Refining, Space Suit Concepts Damon Ellender – Metals Manufacturing, Gas Plant Design Gary Fisher – Waste Treatment Sys Inka Hublitz – Agriculture William Johns – Psychological Factors K. Manjunatha – IT / IC / Communications Joseph Palaia – Electrical & Nuclear Sys Georgi Petrov – Settlement Architecture Richard Sylvan - Medical Factors

Mars Homestead Project Settlement Concept

Importance of Electrical & Nuclear Systems, and key guiding principles Never before in the course of human history have we been so dependant on our technology for survival. • Energy will be the lifeblood of any permanent settlement on Mars. • Needed to extract water, air and minerals and to process them into useful products. IE for MRM (Mining, Refining & Manufacturing) systems. • Understanding of settlements loads, and load locations is critical. • Multiple redundant power sources and distribution channels required. • Desire to manufacture many system components from local materials. • Both electrical energy and thermal energy have important roles to play.

The Paschen Curve – Special Consideration Mars ~2 k. V/cm Earth Sea Level ~25 k. V/cm

Energy Sources - Potential Nuclear Reactors Nuclear RTGs Solar Thermal Engines Wind Turbines

Thermal Energy Sources - Selected Thermal to electrical energy conversion assumed ~20% efficient.

Electrical Energy Sources - Selected During day, one reactor elect output = 0, thermal energy to MRM. Greenhouse lights only at night.

Overview of Nuclear Reactor Design • Concept developed by MIT Nuclear Engineering Dept. (Presented at Mars Society Convention 2004) • 400 k. We, 2 MWth • 25 year EFPL (Effective Full Power Lifetime) • CO 2 coolant, insensitive to leaks or ingress • Shielded by Martian soil, rocks and water • Hexagonal block type core (slow thermal transients, large thermal inertia) • Epithermal spectrum • Dimensions L=160 cm, D=40 cm • Mass 3800 kg • Fuel 20% enriched UO 2 dispersed in Be. O • 20% efficient Brayton cycle energy conversion, both open and closed cycles possible.

Power System Locations Graphic by Georgi Petrov. Copyright © 2005 by Mars Foundation. Used With Permission.

Active Power Control & Monitoring • Smart appliances / loads which interface with control computer. • Real-time load monitoring and control. • Load scheduling & prioritizing. Energy allocated accordingly. • Conserves energy and increases availability. • Manual bypass / override function provided. “Open the Pod-Bay Doors Hal” “I’m sorry Dave, I can’t do that. ”

Failure Mode Analysis • Daytime available electrical power is reduced because of MRM use of high quality heat. In contingency, shut down or reduce MRM. • Reactor systems N+1 redundant at night, N+2 redundant during the day. • In case of double reactor failure, plants in artificially lit greenhouse die. Settlers survive off of the sun lit greenhouse and stored food until a replacement reactor arrives from earth. • In case of triple reactor failure, emergency loads are powered by methane generators using stored methane, and by the solar energy system. Emergency Loads

Settlement Electrical Energy Demand

Settlement Electrical Energy Demand

MRM Electrical Energy Demand

MRM Thermal Energy Demand

Energy Distribution System Voltages • Main distribution is at 480 V 3 phase. • Distributed transformers convert to 240 V or 120 V 1 phase. Wiring • Require redundant paths to prevent single point failures. • Need to provide 3 different voltages to loads distributed throughout the settlement. Switchgear & Interconnects • Need switchgear to prevent large zone outages (more switchgear, more independent zones, but also more Earth imported mass). • Power interconnect provided between settlement power grid and tuna can habs / construction trailers. • 120 V interconnects provided, normally open.

Settlement Layout

Energy Distribution Grid

Significant Agricultural Energy Loads • Greenhouses sized for 12 settlers • ~450 k. We Load for Opaque Greenhouses! • 50% duty cycle – operate at night

Electrical System Components Earth Import or Mars Manufacture? Rule of Thumb: High Mass, Low Tech – Make on Mars Low Mass, High Tech – Import from Earth Total Mass From Earth: 7 tons Total Volume from Earth: 30 m^3 Mars Manufactured Items: 37 tons of Mars derived materials. Desired Mars Obtained Materials: • Metals for wire, rods, cable trays, conduit • Plastics for wire insulation, cable trays, conduit • Possibly ceramics for insulators & oil for transformers. Required Masses: • Plastic 150 kg, Steel 8 tons, Aluminum 28 tons, Ceramics & Oils ? kg

Settlement Construction Staging Plan Phase 1 • Completely Robotic. No humans on site. • Timeframe : First 2 years. • Objectives : Deploy first nuke, well drilling equipment, gas plant. Establish water well and initial gas reserve. Phase 2 • 4 People on Site • Timeframe : Second 2 years. • Objectives : Deploy and setup mining / refining / manufacturing equipment. • MRM production runs. Produce material needed for settlement construction. Phase 3 • 8 People on Site • Timeframe : Third 2 years. • Objectives : Continued MRM as needed. Settlement shell construction. No settlement electrical loads yet. Construct shell around agriculture, manufacturing & nuke BOPs. Phase 4 • 12 People on Site • Timeframe : Fourth 2 years. • Objectives : Finalized settlement construction. Commissioning. All settlement loads coming online.

Settlement Construction Staging Plan

Summary & Conclusion • Power generation and distribution is of critical importance. • Nuclear reactors are essential • Provide copious amounts of thermal and electrical energy. • Allow existence of a “power-rich” environment. • Large amounts of high quality heat key asset for MRM. • Reactors can be designed for long lifetime and utilize on site materials for shielding and coolant. • Required settlement electrical loads are manageable. • Many redundant levels incorporated into concept, provides additional capability under normal conditions. • Electricity distribution system leverages use of locally derived materials for many components. • Greenhouse electrical loads are considerable (photosynthesis is just not very efficient!). High load managed through lighting greenhouse at night, operate MRM during the day. • Settlement construction staging allows positive power balance.

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