A Plan for the Human
Habitation of the Solar System
Prof. David Hyland
First SPACE Retreat
Tenerife, 2013
The Question

Can humanity spread throughout the solar
system beyond the Earth, using only
technologies that already exist or are presently
in an advanced stage of development?
(No warp drives, matter transmit beams,
dynamic Casimir thrusters or artificial gravity
that does not use rotation, etc., etc.)
First step: Escaping the gravity well (cheaply)
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Attempt no “all purpose vehicle”. Separate functions,
simplify components, build infrastructure
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Establish a “garage” of reusable reentry vehicles in LEO
Use ELVs to transport both humans and cargo to LEO.
Expectation is that human explorers will subscribe to an
extended stay.
Design upper stages to be disassembled into standardized
components that are used to build infrastructure and habitations
Bare-bones launch vehicle to orbit; transfer to space
habitat; remain for indefinite mission period; transfer to
reentry vehicle: return to earth
Bootstrapping to the Stars
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At all stages of development, use bootstrapping
to finance activities
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With minimum initial investment, start selling
products (on Earth) based on dual use technologies
As revenue increases, set aside earnings for R&D for
the space application
Avoidance of big investors permits the enterprise to
maintain its focus on the ultimate goal of human
space habitation
Progress step-by-step, paying your way as you go
“Habitation Technology” (HT)

HT = An integrated and portable system of technologies
that enable a small group of humans to generate their
consumables, mine local resources, and fabricate and
repair their own tools.
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Energy extraction and power generation
Compact, high yield agriculture
Waste processing and recycling
Atmosphere maintenance and recycling
Water recycling
Metallurgical exploration, extraction, processing and recycling
Rapid fabrication technology
Autonomous system control software
“Habitation Technology” (HT) Bootstrapping
Space Habitation
Aggregate
R&D
In situ energy extraction/power
generation
Compact, high yield agriculture
Waste processing and recycling
Terrestrial Application
First Step in Sustained Human Presence
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First step: Launch two habitation modules (of modest
dimensions). These are robotically capable of preparing
for habitation ( Inflating, pressurizing cabins, etc.)
Send human crew who will exit the launch vehicles and
enter, via ELV, the habitation modules.
The crew connects the two modules with a long cable,
spins it up to produce a “bola” system, and conducts the
first comprehensive experiments on the human
requirements for artificial gravity during prolonged
spaceflight.
 In 5 decades of manned spaceflight, we still do not
know how much “g” is needed to keep humans
healthy indefinitely
Design Driver: Countering 0-g Effects
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There is no completely satisfactory approach to
countering 0-g effects aside from sustained artificial
gravity.
We do not know how much “g” is required to maintain
human health indefinitely (besides zero g = bad, and
one g = good)
We will not know the answer to this for a long time, since
long term experiments are required.
Therefore, we require:
 1 g artificial gravity.
 Acceptable levels of Coriolis effects
 Exposure to 1g almost all the time
Orbiting Bolas = The first module in a series of permanently
habitable platforms that return investment in space habitation
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Establish long-term
habitability requirements
and solutions (gravity
and radiation protection)
Partial implementation of
HT
Space tourism
Orbital debris clearance
and reclamation (moves
several steps toward
asteroid mining)
Test novel manufacturing
processes exploiting
vacuum and 0-g
2nd Step: Build infrastructure to enter the Interplanetary Super
Highway
Establish Bola work
stations and fuel
cashes at the EarthMoon, Sun-Earth L1
and L2 points
 Tourism
 Moon base transfer point
 Astronomical
observatories
 NEA detection and
monitoring
Bolas combine in an interplanetary space ship!

Take a Bola with 4 hab modules, add a
walkway, cross truss, standoff truss and
tensioned cable system  an interplanetary
craft with sufficient room for the full habitation
technology
12
Interplanetary Spacecraft = Space Habitat with Propulsion
 Up to 3 yrs. Trip Time
12
Crew Members
 Full complement of habitation technology
 The Bola morphs into two
segments of a torus
 Essentially the smallest selfsustaining system that can
support a dozen people
 Can add hab modules and
load-bearing cables to get
a full torus (~150 people)
Rotation Axis
Bola Two Segments of a Torus!
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Embed the hab modules in a
stiff, light tensioned cable,
compressed column
structure – a proven approach
to precision space structures.
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Note:
 Cross truss and rotation axis column serve to
give sufficient stiffness.
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 Cross truss supports agg modules
 Propulsion engines located at tips of cross
truss. Protects Hab and Agg modules from
radiation. Provides control authority for both
cm acceleration and rotation control
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Cables carry most of the
centrifugal loading
Junctions are statically
determinate, permitting accurate
analysis
Stiffness is provided in all six rigid
body hab module degrees of
freedom.
Lowest vibration modes avoid
frequencies that induce motion
sickness
Design is expandable by
adding more hab modules and
more supporting cables
14
Initial Deployment: Spiral out to E-M L1
Start in 300 km circular orbit
about Earth
Forbidden
Zone
Spiral out to a coasting
trajectory to the E-M L1
“throat”.
Meld into the Lyapunov orbit
of L1 Station and refuel
Propellant mass: 20 MT
Trip duration: 5.6 months
385  10 km
3
The L1/L2 region is the
gateway to interplanetary
space – where the
spacecraft can “earn its
keep”.
NEAR-EARTH OBJECTS AS FUTURE RESOURCES
The comets and asteroids that are potentially the most
hazardous because they can closely approach the Earth
are also the objects that could be most easily exploited
for their raw materials.
This is why low energy trajectories through the interior and
exterior realms of the Sun-Earth system are of key importance
It has been estimated that the mineral wealth resident in
the belt of asteroids between the orbits of Mars and
Jupiter would be equivalent to about 100 billion dollars
for every person on Earth today.
But we do not go to plunder the solar system of precious
metals and deliver them to Earth, but to build new human
communities in space.
Extractive economy? Development economy!
From E-M L1 to S-E L2: Start of the First grand Tour (for mining)
 After refueling, leave L1 on the
outward invariant manifold.
 Swing by the Moon and exit the
E-M L2 throat in time to meld
with a heteroclinic orbit leading to
the Sun-Earth L2
 Take one turn around the
Lyapunov orbit and enter the
external domain of the Sun-Earth
system
L1
Lyapunov
Orbit
Moon
E-L1 to S-L2: V=12m/s, 50 days
Orbit of the
Moon
122,720 km
L1
Sun
Earth-Moon Frame
Sun-Earth Frame
L2
L2
Asteroid Mining Tours: Exterior Realm
1.
Drop off cargo at L1 Station. Leave L1 Lyapunov orbit.
Follow heteroclinic orbit to L2 (pink line, left to right)
(drop off cargo at Earth-Moon system)
2.
Meld into L2 Lyapunov orbit, follow for ¾ of a period,
then follow the unstabile manifold (green line, heading
down)
L2
Sun-Earth System
L1
3.0 million km
Sun-Earth Frame
Through S-E L2 to the Grand Tour of the Exterior Realm
3. Follow the
homoclinic,
exterior domain
orbit (green path
issuing from L2
and going
clockwise)
Apophis
4. Mine Amors
and Apollos on
the way (3
years)
Sun
Then: see next
slide
3-2 resonance
1 AU
Heteroclinic Transfer Between Exterior and Interior Realms
5.
Follow homoclinic exterior domain orbit to L2 on the stable
manifold (green line, pointing down, left). Refurbish and
repair at L2 Station
6.
Meld into L2 Lyapunov orbit, follow for ½ of a period, then
follow the heteroclinic orbit to L1 (pink line, right to left).
L2
Sun-Earth System
L1
3.0 million km
7.
Deliver cargo to Earth-Moon system. Meld into L1 Lyapunov
orbit, Exchange crew and refuel at L1 Station.
8.
Follow Lyapunov orbit for one period, then follow the
homoclinic interior domain orbit (blue line heading to the left)
Through S-E L1 to the Grand Tour of the Interior Realm
Forbidden
zone
Apophis
9. Follow the
homoclinic, interior
domain orbit (red
path issuing from L1
and going counter
clockwise)
10. Mine Atens and
Apollos on the way
(two years)
Sun
3-2 resonance
11. Then follow the
stable manifold to L1
(blue line in previous
slide, heading to the
right).
12. Refuel and
exchange crew at L1
station.
Go to step 1 and
repeat.
NEAR-EARTH OBJECTS AS FUTURE RESOURCES (cont.)
Whereas asteroids are rich in the mineral raw materials required to build
structures in space, the comets are rich resources for the water and carbonbased molecules necessary to sustain life.
In addition, an abundant supply of cometary water ice could provide large
quantities of liquid hydrogen and oxygen, the two primary ingredients in
rocket fuel.
As we begin to colonize the inner solar system, the metals and minerals found
on asteroids will provide the raw materials for more infrastructure, space
colonies, and space ships. Comets will become the watering holes and gas
stations for the interplanetary spacecraft.
Reference: Lewis, John S. Mining the Sky: Untold Riches from the Asteroids, Comets
and Planets. Addison-Wesley, 1996.
Deep Space Voyagers becomes Space Colonies
“Mature” some spacecraft,
growing them into complete tori
and plant them as permanent
stations (for resupply, repair and
R&R) at Lagrange points or other
orbital transfer points
Crew of 12
Colony of 150
For cargo or conventional vehicles, the interplanetary
spacecraft can be complemented by the Rotovator
2Vo
Vo
Between cargo launches,
an on-board low thrust
propulsion system
performs orbit
maintenance
Cargo is released
at 2V0, placing it
into a hyperbolic
escape orbit
 = 2Vo/L
Surface of planet
Rotovators combine the efficiency of high Isp propulsion with the high
thrust of chemical propulsion (but without chemical rocketry)

To design the rotovator, we need to find the variable cross
section that will keep axial stresses below the ultimate
yield stress of the material
A(s) = r2(s)
 = 2Vo/L
s
Volumetric mass density = 
L/2
The cross - sectional radius that makes the axial stress equal to a specified value, σ, is :
 v2

r s = rt exp - t 2
 4V
 
where :
  2s 2  

 - 1 
 L 



v t = ΩL 2 = tip speed = orbit velocity = Vo
σ
( This is the key parameter!)
ρ
2
2




v
v
VL
3 2


Total Mass = ρπ rt2
exp  t 2  (when  t  ≫ 1)
V
vt
 2V 
 
V = tenacious speed =
A Sample of Material Properties
tenacious speed = (Tensile modulus/ density)1/2
Property
Tensile Modulus
(109 N/m2)
Breaking
Tenacity
(109 N/m2)
Density
(103 kg/m3)
Modulus speed
(km/s)
Tenacious
speed
(km/s)
Kevlar 29 (w/resin)
83
3.6
1.44
7.59
1.58
Kevlar 49 (w/resin)
124
3.6
1.44
9.28
1.58
S-Glass
85.5
4.59
2.49
5.86
1.37
E-Glass
72.4
3.45
2.55
5.33
1.16
Steel Wire
200
1.97
7.75
5.08
0.504
Polyester
13.8
1.16
1.38
3.16
0.915
HS Polyethylene
117
2.59
0.97
11.0
1.63
High Tenacity Carbon
221
3.10
1.8
11.1
1.31
Carbon nanotubes
13,000
130
1.3
100
10
Material
Rotovators can be fabricated within current technology
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Rotovators can be made much smaller and
much less massive than space elevators
Exotic, untested materials with enormous
strength-to-weight ratios are not required
Can be fabricated from asteroidal materials
Can be made as free-fliers (called rotors) for in
space orbit changes with large Vs
Can be stationed at the L1/L2 gateways to
boost vehicles to Mars and beyond
The Rotovator (Rotor) as an Orbit Raising
Device
2Vmax-VLEO
L1
Cargo in LEO
Vmax
Rotovator in
elliptical orbit
o Cargo vehicle in LEO. Rotovator in elliptical orbit with rmin = rLEO+ L/2
o One end of rotovator hooks up with cargo. Rotovator makes one half
turn and releases cargo at speed 2Vmax–VLEO
o Cargo travels on a much more eccentric ellipse – out to near L1
o Then cargo proceeds via a low-thrust trajectory to lunar orbit
Toward the Habitation of the Solar System
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Send deep space voyagers to take up stations near the
Moon, Mars, Mercury and the moons of Saturn and
Jupiter
From these orbiting stations, plant ground-dwelling
settlements with habitation technology modules
(provided that adequate “g” is much less than 1g.)
Habitation technology modules will also be planted on
Earth (perhaps in otherwise uninhabitable areas).
We will build a community of communities spanning the
solar system – an Oikoumenê of many worlds!
An off-Earth economy will begin to grow – and
ultimately dwarf that of Earth
Homes for all Mankind
Rare minerals and metals
Advanced zero-g manufacturing
Protection of the Commons
Discovery and new knowledge
Invention and scientific advance
What will life be like?
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Small human communities will be spread across great distances
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Ethical norms are shaped by one’s way of life
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Transport of bulk materials impractical
Trade in rare commodities and devices
Mainly trade in ideas, inventions and discoveries
Space inhabitants confront cosmic necessities (not a man-made world)
Truthfulness in everything is everything!
Word of honor, not litigation. Generosity not acquisitiveness
Enough for everyone is a feast!
Every human being will be precious
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Capital will bid for labor. People too few, not too many
Oikoumenê of many worlds = The Household
A New Civilization?
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In undertaking a great journey, people must choose
what to take along and what to leave behind.
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The choice demands a decision about the most precious human
experiences
Every society has as its basis a fundamental human
experience.
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Helenic – Beauty
Siriac – Ultimate Spiritual Reality
Western Christendom – Power of the Machine
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Why not: Curiosity, Thrill of Discovery, and Awe?
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The Answer: Yes!
Ad Astra!