ZENITH SYSTEM DESIGNS”ALWAYS LOOKING UP”

Blaise Cole, Paola Alicea, Jorge Santana, Scott Modtl, Andrew Tucker, Kyle Monsma, Carl Runco

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.

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.

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

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

Two Main Questions Simulating 1g in space Minimizing weight needed for shielding

while still providing sufficient protection

Gravity Load

1g

0.035 g

Limit of low

traction

6 m/s rim speedApparent gravity

depends on direction of

motion

4 rp

mO

nset

of

mot

ion

sick

ness

Comfort zone

Artificial gravity becomes more “normal” with increasing radius

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

70 72 74 76 78 80 82 840.8

0.85

0.9

0.95

1

1.05

1.1

G Levels at 3.25 rpm of Living Pod

Main LivingRecreationMiscExperimentalAirlock

Radius from central spin axis (m)

G

Initial Design: Armstrong 1

STRUCTURAL MASS + SHIELDING: ~370 MT

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

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

• 920 m3 at 1g (Bottom Floors)• Meets 47 m3/per person

requirement

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

14m

3m

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

3m

14m

Propulsion and Power Generation

Airlock and Addition Storage

Experimentation/Controls/Communication

Life Support/Filtration/Waste

Detailed Design of Truss and Tube

Truss Structures(4):• Material: Carbon Fiber• Mass: ~80 MTTubes(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

60m

3m

3m

http://www.atk.com/capabilities_multiple/deployable-structures.asp

Thermal Calculations All external surfaces coated in Paladin

Black Lacquer Absorptivity α = 0.95 Emissivity ε = 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)

Propulsion Selection

RS-68 Nuclear VASMIR HiPEP

Engine Mass 6.6 MT 10 MT 7.6 MT 190 MT

Thrust 3.37 MN 294 kN 47.5 N 33.5 N

Fuel Mass 544 MT 119.5 MT 32.6 MT 25.6 MT

Burn Time 11.9 min 99.7 min 389 days 781 days

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

Power Trade-offsSolar Nuclear (LFTR) H2 Fuel Cell

Pros:

•Power from external source

•Long lifespan•High output•Low weight•Allows expanded design•Easy to re-fuel•Robust

•Excellent Power/Weight•Same fuel as prop.•Produces water

Cons:

•Expensive•Low Power/Weight Ratio•Exponentially decreasing power away from sun•Requires pointing•Easily damaged

•Requires containment shielding•Requires heat exchangers

•Requires extra Oxygen•Requires extra H2•Harvesting fuel not practical

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

Power System Power Budget

Oxygen Regeneration 28 kWHVAC 5 kWLighting 1 kWControls/Computers/Guidance

(<) 5 kW

Communications (<) 4.6 kWMaximum Total 43.6 kW (all systems

running)• 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

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

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

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

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

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

The End

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.

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

ITEM MT Kg COSTLIVING POD 3.98 3,980 $7,164CENTRAL HUB 2.38 2,380 $2,618TRUSS STRUCTURE

80 80,000 $144,000

TUBES + SHIELDING60% HDPE 1.21 1,210 $1,33140% AL 0.806 806 $1,450LIVING POD SHIELDING

193.52 193,520 $212,872

FUEL + TANKS 37.6 37,600 $233,200VASIMR 7.6 7,600 ~$40MPOWER SYSTEM 4.7 4,700 ~$10MLAUNCH ~$150M/launch

(14)WATER 5.44 5,440 $ 3,000TOTAL 403.666 403,666 ~$2.14B

* THIS DOES NOT INCLUDE TESTING OR FABRICATION COST!

Estimated Material Cost Analysis

Additional Information Other design configurations of

Armstrong 1

Addition Information If launching is a problem, the following

design is compatible with current heavy launch systems

Armstrong 2

Additional Information Other design configurations of

Armstrong 2