Zenith System Designs ”Always looking up”

1. Zenith System Designs”Always looking up” Blaise Cole, Paola Alicea, Jorge Santana, Scott Modtl, Andrew Tucker, Kyle Monsma, Carl Runco

2. Mission Statement • Our mission is to expand the domain of humanity beyond the Earth for the betterment, preservation, and advancement of all humankind by creating a mobile habitat capable of long-duration, exploratory voyages while ensuring the physical and psychological well-being of its inhabitants.

3. Objective Goals • Trips > 24 months duration • Assume at least a 12 member crew • Minimum resupply from Earth • A space-only craft (no atmospheric flight or re-entry) • All technologies must be credible based on current capabilities and trends. • Design the system so it can be deployed incrementally.

4. Uses for the Habitat • Long duration experiments in gravity between 0-1g • Agricultural experiments/food growing under varying gravitational loads • Lead towards self sustainability • Prove and develop long duration flight technology • Provide an intermediate stepping stone towards truly interplanetary spaceflight

5. Mission Profile • Construct incrementally in Low Earth Orbit. • Propel fully assembled and supplied, unmanned vehicle to Earth-Moon L1 point using electric thruster. • Estimated trip time: 389 days. • Crew rendezvous with spacecraft upon arrival at L1 point.Crew arrive by small conventional spacecraft. • Crew brings additional fuel for propulsion

6. Two Main Questions • Simulating 1g in space • Minimizing weight needed for shielding while still providing sufficient protection

7. Artificial gravity becomes more “normal” with increasing radius 0.035 g Limit of low traction 1g Comfort zone 4 rpm Onset of motion sickness 6 m/s rim speed Apparent gravity depends on direction of motion Gravity Load

8. Gravity Calculations • Rotating at 3.25 rpm with a radius of 85 m for 1 g • Avoids rpm that cause motion sickness while providing 1 g

9. Initial Design: Armstrong 1 STRUCTURAL MASS + SHIELDING: ~370 MT

10. Shielding Details • Living Pods Shielding • Material: HDPE • Areal Density: 10 g/ • Surfaces fully shielded • MASS: 193.52 MT • Central Hub Shielding • Material: HDPE • Areal Density: 10 g/ • Upper Module • MASS: 71.13 MT • 30 Sv/yr max. dosage rate • Achievable with 10g/cm2 Polyethylene • Shielding located behind pressurized hull to prevent outgassing • Crew uniforms will include material to reduce experienced dosage

11. Detailed Design of Dome Crew Space • For both crew spaces total: • Material: Aluminum 7075-T73 • Hull Thickness: 0.73 mm • Mass of Structure: 3.98 MT • Full Shielding Mass: 193.52 MT • Total Living Space Provided: 3700 m3 • 920m3 at 1g (Bottom Floors) • Meets 47 m3/per personrequirement • Features: • Ease of production • Contains several floors • Larger living space than the Bell design • Less surface area to shield than a torus • If one pod were to fail, crew could feasibly all live on one side in emergency situations 3m 14m

12. Detail Design of Middle Section • Material: Aluminum 7075-T73 • Hull thickness: 0.73 mm • Mass of structure: 2.38 MT • Shielding mass: 71.13 MT • Lower propulsion modules remain unshielded • Features: • Made in expandable sections so other units can be added on to the middle hub • Allows for more storage space, docking capabilities, central hub for passage between other modules • Still allows for zero gravity capabilities • Will contain the power supply, life support systems, and propulsion systems Airlock and Addition Storage Experimentation/Controls/Communication Life Support/Filtration/Waste Propulsion and Power Generation 3m 14m

13. Detailed Design of Truss and Tube 3m 60m 3m • Truss Structures(4): • Material: Carbon Fiber • Mass: ~80 MT • Tubes(2): • Material: 60% HDPE, 40% Al • Mass: ~2.012 MT • Features: • Collapsible truss/tube system can be launched in a single load (ATK Articulated Mast System) • 50-50 truss-cable load distribution • Tubes include radiation shielding and will help truss stiffness • A ladder will be placed inside to help the transition from differing gravities http://www.atk.com/capabilities_multiple/deployable-structures.asp

14. Thermal Calculations • All external surfaces coated in Paladin Black Lacquer • Absorptivityα = 0.95 • Emissivityε = 0.75 where = Intensity of Sun Radiation A = Projected Area absorbing or radiating σ = Stefan-Boltzmann Constant • = 20.5°C = 68.8°F (Spin axis normal to sun) • = 18.6°C = 65.4°F (Spin axis parallel to sun)

15. Propulsion Selection

16. Propulsion Information • 1.9 MW VASMIR Engine • MASS: 7.6 MT • THRUST : 47.5 N • Isp: 5000 s • LH2 Fuel and Tanks • FUEL MASS: 32.6 MT • TANK MASS: 5 MT • VOLUME: 460000 L • 10 N thrust for 90 days required for spin-up

17. Power Trade-offs

18. Power System • Liquid Fluoride Thorium Reactor (LFTR) • Lightweight (operates at 1 atm, no pressure vessel) • Liquid fuel inherently safer (requires active process to avoid passive shut-down) • Components less complex and less expensive than traditional designs • Thorium plentiful on Earth and Moon (Inexpensive fuel) • >2 MW Possible in small footprint • Closed Cycle Steam Turbine System • 300 kg water supply needed for coolant

19. Power System • Power Budget • Why a LFTR? • Human exploration to farther destinations will require more power than is feasible with solar power • Lightweight system ideal for spaceflight • Ample power able to support an expanded future design • Power available for all systems simultaneously, with room for electric propulsion use • Emergency Power • Hydrogen Fuel Cell (feeds off propellant tanks) • Small Deployable Solar Panels

20. Food and Water Requirements • Water • 3 gal/person/day • 95% efficient recapture system • 1500 gal for a 2 yr. mission • 5.7 m3, 5.44 MT • Food • Preserved/Freeze Dried • 2000 calories/person/day • 16 m3, 13 MT for a 2 yr. mission

21. Life Support • Oxygen Re-captured by thermally breaking CO2 covalent bonds. • Requires 28kW/15 min. burn, & 1 burn/day • Emergency Backups • Li-OH Scrubbing • Oxygen Candles

22. Estimated Timeline to Build and Complete • Stage 1 (36-48 months) • Design of Living Systems and Main Module • Design and fabrication of Truss sections • Preform testing of docking and construction in a simulated 0 g environment. Testing and design of rocket configurations. • Stage 2 (18-24 months) • Launching components into space to start construction before moving to L1. • Stage 3 (13-15 months) • After building is complete, supply and begin launch into L1 • Stage 4 (4 days) • Send astronauts into space to rendezvous with Armstrong 1

23. Launch Considerations • Soyuz inexpensive since the design cost has been spread over so many missions. • If we have many launches, economies of scale will become applicable, driving costs down per launch. • Atlas V considered most viable launch vehicle for our needs, however modules can easily be split and sent using smaller vehicles. • Current estimate is that 14 launches will be needed for assembly in LEO, and an addition launch will be needed for the astronauts rendezvous

24. Advantages of this Design • Modular design can be assembled in pieces at a desired location • Modular design allows for expansion and different payloads/configurations • LFTR provides ample power for expanded configuration, and provides limitless oxygen • Design can be moved within the Earth-Moon system comparatively inexpensively using electric propulsion • Vehicle can idle almost indefinitely without crew aboard

25. The End

27. Derived Requirements • The spacecraft must have a propulsion system and sufficient propellant to be capable of moving itself out of Earth orbit, delivering the vehicle to its destination, and returning to Earth orbit, all within the specified mission lifetime. • The spacecraft will have self-contained life support systems capable of supporting a minimum of 12 crew for at least 24 months, and will provide them protection from all environmental factors including radiation. • The spacecraft will have dimensions sufficient to contain all support systems and cargo, and provide sufficient living space to the crew. • The spacecraft will have an amount of artificial gravity sufficient to maintain crew health for the duration of the mission. • Artificial gravity will be generated in a manner that reduces motion sickness. • The vehicle must carry sufficient provisions for the crew to sustain them for at least 24 months. • The electrical power system must be capable of generating sufficient power for all systems. Power must be continuously generated at or above this level for the duration of the mission. • The vehicle will contain features to allow the docking of external vehicles. • All equipment will be launched by currently available payload delivery systems.

28. Detailed Design of Truss and Tube cont. • Maximum stress will occur either during spin up or de-spin • Maximum force due to acceleration was calculated to be less than 1kN. (50kN load test shown above) • Maximum displacement was found to be 26mm

29. Estimated Material Cost Analysis * THIS DOES NOT INCLUDE TESTING OR FABRICATION COST!

30. Additional Information • Other design configurations of Armstrong 1

31. Addition Information • If launching is a problem, the following design is compatible with current heavy launch systems Armstrong 2

32. Additional Information • Other design configurations of Armstrong 2