© 2014 Systems and Proposal Engineering Company. All Rights Reserved Design of Two Near Term...

© 2014 Systems and Proposal Engineering Company. All Rights Reserved

Design of Two Near Term Commercial Space Stations Using Innoslate

Keith A. Taggart, Ph.D. and Steven H. Dam, Ph.D., ESEP


Why Commercial Space Stations?• Need to have business case for being in

space requires near term value obtainable from activities that can be conducted either only in space or more inexpensively in space

• Business cases for space tourism and mining/manufacturing have been made

• However, where are people going to visit, work and live?

Space stations are one option, but how can we make them affordably?


Two Space Station Concepts

Type 1

Type 2

ByKeithTaggart


Key Usability Requirements

• 35 m radius at 3 rpm gives .35 g– Result of trade between gravity, coriolis force, and

size/cost/construction time

• Total volume under gravity 3300 m3 or 117,000 cubic feet• Total floor space under gravity about 7200 square feet

– One Module is about 300 square feet– A nice hotel room or office or lab

• These stations could support: ― Closed Environment Research― Space Tourism― Space Based Manufacturing ― Space Based Power Assembly

and Testing ― Asteroid Exploration― Research for Radiation

Mitigation Techniques ― Satellite Repair

― Research in Long Term Effects of Low Gravity (not micro gravity) Environment

― Low Gravity Research in General

― Plant Growing in low gravity― Lunar Exploration and

Resource Exploitation― Debris Collection


Potential Construction Constraints• Modular Construction• 7m long x 5 m diameter modules• 24 to 30 modules Plus• About 35 Falcon Heavy Launches

– Roughly One a Month– 40 metric tons per launch to roughly 300km– Modules fit in Falcon Heavy Shroud – Plus – Radial Members, Couplings, Initial Crew Quarters

• About 12 Falcon 9 Launches– Construction Crew of 6 Serves for 9 Months– Supply Launch at same time as crew launch– Additional Supply Launch at 4.5 Months

• Construction Time About 3 Years– Modules are plug and play– Much assembly work can be done by teleoperation– Operators must be close at hand to avoid latency problems


Module Construction

• Module Structure Mass M=(3.1+5.9+4.2+2.0) metric tons– M=15.2 metric tons

• Available Launch Mass– M=40 metric tons

• Five Layer Shell– Insulation / Impact - Orange

• 1cm Mylar and Kevlar Layers, white surface • M=220x.01x1.4=3.1 metric tons

– Pressure - Blue• 2x0.5 cm Aluminum • M=2x220x.005x2.7=5.9 metric tons

– Sealant - Green• 1 cm Seals small holes • M=220x.01x2.0=4..2 metric tons

– Interior - Red• .5 cm Structural Plastic, Foamed Core • M=(220+60)x.005x1.4=2.0 metric tons

Falcon Heavy Provides 160% Launch Margin

Work / Living

Utilities

DownHall

Utilities

~3m

~2.5m

~1.5m


“Back of the Envelope” Cost Estimates

Launch Costs• 35 Falcon Heavy Launches

– 35x40 metric tons=1400 metric tons to about 300 km– 35x120 M$ per launch = 4.200 B$

• 8 Falcon 9 Launches– 4 x 6 Construction Crew– 4 x 10 = 40 Metric tons of supplies– 8 x 56 M$ per launch = .45 B$

• Total Launch Costs to Construct– 4.7 B$

Construction Costs (Much Less Precise)• 30 Modules at 100 M$ each equals 3.0 B$• Crew Cost

– 18 person years x 8760 hours per year x $1000 per hour equals 160 M$– Equipment and Supply Cost 200 M$– Ground Support 200 M$– Fudge Factor 400 M$

• Total Construction Cost about 4.0 B$

Total Costs About 9 B$


Operating Cost Issues• Supplies and Trash Removal– 10 Permanent Residents– 10 Visitors

• Food– Assume 3000 calories per day per person– Assume 3 calories per gram– One kilogram of food per person per day– Multiply by 2 for “packaging” gives about 15

metric tons per year – Roughly the same amount of waste needs to

be returned to earth• Supplies, including food, water, and other

consumables could be handled with weekly or bi-weekly visitor transport on Reusable Falcon 9 launches


Operating Cost Issues (continued)

• Recycle versus Renew– 4.3 Metric Tons of Atmosphere

• 5 Metric Tons of Reserve in Pressurized Storage• 1% loss per week• About 5 Metric Tons Replacement per year

– Water• 40 gallons per person per day• 0.15 cubic meters• 20 people need 3 cubic meters or 3 metric tons per day• Assume a week to recycle the water with 1% loss • Requires 21 cubic meters of water stored• Plus 0 .21 cubic meters replacement per week or • About 12 metric tons per year

– If Recycle Efficiency Falls below 95% per week then replacement cost could become problematic.


Difficulties / Opportunities

• Power• Radiation Protection• Orbital Debris

– Collision Protection– Collision Avoidance

• Station Dynamics and Control– Orbital Change of a Spinning Station– Attitude Control– Spin Control

• Recycling– Atmosphere– Water– Waste

• Economic Viability• Liability / Insurance

“A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty.” Winston Churchill


Applying MBSE

• To take this design to the next stage, a number of systems engineering trade studies needs to be applied to this initial architecture

• Creating system models of this architecture will support the trade studies and enable more detailed design work

• We begin by identifying the requirements embedded in the design


Requirements Analysis


Functional Analysis


Discrete Event Simulation

• Execution of model provides timing, resources and costs


Cost Profile from DESCo

st (M

$)


Other Analyses

• As the work progresses, we can capture risks, key decisions, related artifacts (e.g., standards, regulations), metrics, results of high-fidelity simulations, V&V activities, and anything else associated with the design

• By providing all this in a collaborative environment (via private or public cloud computing) we can bring large teams together


Summary

• We have just begun to explore the utility of commercial space stations

• Applying MBSE techniques during the architecture phase enables more robust trade-offs

• Having a scalable, integrated tool cuts time, and therefore costs, that can then be applied to great quality and profitability

© 2014 Systems and Proposal Engineering Company. All Rights Reserved Design of Two Near Term...

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