This was our second submission into the Nasa Design Competition.

1. NASA 3D Printed Habitat Challenge • August 2015
Outpost Olympus
An architectural concept for a Martian habitat based off basalt composite
deposition techniques
2015-1-124
T
o our early ancestors, a northern euro-
pean winter would have seemed an in-
hospitable wasteland. Only with persis-
tence, experimentation and innovation were
these areas made habitable. Now, people flour-
ish on every continent of this world we call
home. Not satisfied with that progress, we ex-
tended our reach past our own atmosphere to
low earth orbit which now supports the contin-
uous presence of our boldest explorers. This
same progress should be carried forward to
the next frontier. With the advent of of the 21st
century, mankind has been presented with an
exceptional opportunity. For the first time, life
on Earth has the ability to spread to another
planet, and we must be decisive as we wade
further into the great cosmic ocean that sur-
rounds us. Mars is the next step on mankind’s
oldest journey. One that began the moment the
first person wondered what was over the next
hill.
Although the only explorers to visit Mars
have been robotic thus far, NASA has dedi-
cated resources in an attempt to establish a
human presence by 2035. With this goal, it
is evident that a habitat with appropriate con-
struction autonomy, crew protection and liv-
ability be developed for long duration visits.
The considerations which drive the habitat de-
sign include the requirements for sustaining
human life as well as those components which
allow for survival in the extreme Martian con-
ditions. The price per pound for a payload
leaving Earth’s orbit is on the order of tens
of thousands of dollars. This leads to a pro-
hibitive cost of hundreds of millions of dollars
for each mission. In order to mitigate much
of this cost, a Martian habitat should be de-
signed to be comprised of in-situ Martian re-
sources. The habitat concept presented in this
paper has been developed with these concerns
in mind. This habitat incorporates an addi-
tively constructed architecture suitable for four
inhabitants to comfortably live on the Martian
surface for at least a year and consists mainly
of Martian materials with minimal amounts of
Earth-based components.
I. Structural Frame
The structural frame of this habitat will be
printed in place as a continuous composite rod.
These rods are comprised primarily of basalt,
a resource found in abundance on the surface
of Mars. Even on Earth, basalt is a popular
construction material due to its high thermal
resistance, radiation resistance, and mechanical
strength and is used as an alternative to steel
rebar. This established process can be adapted
to additively and autonomously construct a
structural frame on Mars (see Fig. 1).
The basalt rocks will be first gathered by
a robot and crushed. Using a mirror system
which focuses solar light to the required tem-
perature of around 1500 C, the basalt is melted.
Molten basalt then flows through a brushing
with a series of holes through which, due to
hydrostatic pressure, the fibers are drawn. By
varying the drawing speed and melting temper-
ature, different fiber diameters can be achieved.
The fibers are then cooled to get hardened fil-
aments and coated with a sizing liquid used
to provide integrity and resin compatibility.
The resulting properties of the basalt compos-
ite make it an excellent construction material
due to its high tensile strength (3,000 - 4,840
MPa compared to a standard steel alloy A36
with 400-550 MPa). With an operating temper-
ature range of -260 C to 980 C, basalt rebar
can withstand the temperature changes within
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2. NASA 3D Printed Habitat Challenge • August 2015
a Martian year. As an added bonus, it is fire-
resistant, making it an ideal material for a habi-
tat [1]. This technique is well documented and
would require few modifications to make it
appropriate for a Mars-based manufacturing
system.
The fibers can be collected and forwarded
to the basalt rod deposition robot which winds
the fibers together and applies the resin which
will convert the flexible basalt fibers to stiff
basalt rebar (see Fig. 2). This curing will be
done continuously as the now stiffening rod
is deposited directly on the construction site
in the desired position and shape. In this way,
long, continuous structural members can be
created for additive, in-situ construction of any
desired shape, including structures other than
the habitat frame. In addition, the majority of
the materials required are found on Mars with
the resin comprising less than 10% of the total
basalt composite mass.
The basalt rod deposition technique pro-
vides the freedom to design any habitat struc-
ture. The architectural concept described in
this paper seeks to echo a frontier aesthetic,
updated for a new planet. The basic frame
incorporates a series of ribs that are formed
from one continuous basalt rod. The ribs are
spaced close enough and designed to support
the weight of the regolith should the habitat
depressurize. To prevent the ribs from collaps-
ing laterally along the structure, supporting
cross-rods are implemented, also from a sin-
gle continuous basalt rod. The cross-rods are
constructed in an oscillatory pattern such that
vertical ribs sit in the valleys of the oscillation,
preventing their lateral movement (see Fig. 3).
Preliminary testing has demonstrated that such
a structure is capable of holding weight with-
out collapsing. It is this innovative architectural
design technique which serves as the core of
the habitat around which all other layers will
be added (see Fig. 4).
The benefits of such a design include the
fact that the architecture concept has been
tested on Earth since it is similar to a Quonset
hut frame. Therefore, it has been proven to be a
simple yet elegant solution to the habitat prob-
lem. In addition, only the frame and flooring
of the habitat will be made from highly pro-
cessed Martian material as opposed to other
methods that, for example, require bricks of
material. The majority of the remaining mate-
rial needed is either reused from the mission
or is unprocessed Martian regolith.
Printing the entire frame of the habitat
from one continuous composite rod has several
advantages. This approach eliminates com-
plex joints between structural members and
also eliminates the complex task of assembling
those members autonomously. This approach
will also be relatively quick to execute com-
pared to the laborious process of creating sepa-
rate structural elements and then assembling
them as a separate steps.
This frame will be held in place by a foun-
dation consisting of Martian regolith mixed
with a binding agent from Earth to form a con-
crete [2]. This concrete will be poured into
a shallow depression that the frame has been
printed into. This will serve to anchor the
frame to the Martian surface (see Fig. 5a).
Inside the habitat, a tiered system will be
used to both break up the space and provide
an accessible storage space under each tier for
the life support systems. Breaking up the space
in this way has been used on Earth as a way
to make smaller floor plans feel larger. With
each tier fulfilling a different role, the crew
can more easily mentally separate their work,
rest and recreation areas. A tiered system will
also be more physically stimulating as the crew
traverses their habitat.
The few internal walls of this habitat, such
as those separating the crew quarters and bath-
room facilities, and flooring will be comprised
of composite basalt plates backed by the same
basalt rods that comprise the frame. To create
these plates, basalt fiber is combined with a
hardening resin and then heat-pressed flat in
the desired shape. The process for construct-
ing the basalt plates is well-documented (see
Fig. 6).
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3. NASA 3D Printed Habitat Challenge • August 2015
II. Environmental Protection
Once the frame and foundation have been es-
tablished, the crew lander will be integrated
into the habitat by moving it to join with a spe-
cially incorporated hole in the frame. This
will allow for the reuse of the lander’s air-
lock for the habitat. Once this is achieved, the
parachutes used during the entry and land-
ing phase by both the construction equipment
and the crew lander can be reused to cover
the newly erected structural frame as a thin
membrane to support the subsequent environ-
mental protection layers (see Fig. 5b).
Inside the structure, a coating of sealant pro-
vides an airtight layer. Sealants along this line
are already used in industry. For example, a
polyethylene composite has been used for ster-
ile packaging, and silicone sealants are used in
construction for insulation seals. However, a
specific sealant designed for this purpose re-
quires further research. This sealant will allow
the airtight seal to easily conform to complex
geometries as opposed to an inflated material
which must be designed beforehand to a spe-
cific shape. In addition, the sealant allows for
the structural rod to pass from outside the seal
to inside the living space, allowing for the con-
struction of the planned tiered system.
On the walls and ceiling of the habitat, the
parachute provides a backing onto which the
sealant can be sprayed or laid (see Fig. 5b). On
the floor, a basalt plate will be laid on top of the
rod structure to provide a supporting layer for
the sealant. In addition, to provide a surface
for the crew such that they are not walking on
the sealant, there will be another basalt plate
above the foam layer.
The average temperature of Mars is about
-55 C with a range from -133 C during winter
to 27 C during the day in summer. Therefore,
to minimize the energy required from the life
support systems to maintain a suitable internal
temperature, an insulation layer is necessary.
The low pressure of Mars’ atmosphere pro-
vides an automatic insulation against conduc-
tive and convective heat transfer. A layer of
vacuum between the concrete anchor and the
floor of the habitat will prevent conductive
heat loss through the floor. The basalt fibers
themselves have low conductivity (on the order
of 0.03 W/mK) so heat will not be conducted
through the frame [1]. Radiative heat loss from
the habitat can be controlled using a reflective
layer, e.g. the parachute covering the frame
can be designed with a reflective side for this
purpose.
The galactic cosmic radiation level on the
surface of Mars is 0.21 cSV/day which exceeds
the allowable exposure of 0.14 cSv/day. This
level of exposure can be reached with a Martian
regolith thickness of 50 g/cm2. With a density
of 1.4 g/cm3, this corresponds to a thickness
of 35.7 cm [3]. To offset the internal pressure
of the habitat, assuming a pressure of 7.5 psi
and Martian gravity being 38% of Earth’s grav-
ity, 10 m of regolith is required. Therefore, to
protect the crew from radiation and to counter
some of the internal pressure, a layer of re-
golith with thickness between these two values
will be added on top of the parachute layer
(see Fig. 5c).
For an overview of the different layers see
Figure 4.
III. Livability
In order to satisfy the day-to-day needs of the
crew over their one year stay, all crew activ-
ity centers required by NASA for long dura-
tion missions are present. This includes per-
sonal hygiene, body waste management, ex-
ercise, recreational, medical, and laundry fa-
cilities. It also includes crew quarters, and a
combined galley and meeting facility. Since
this mission is of exceptionally long duration,
enough floor space is devoted to crew quarters
to allow a separate room for each crew mem-
ber (see Fig. 7). Each room will fit a bed and
sufficient standing space for the donning and
doffing of clothing in private. This should en-
hance morale by allowing each crew member
access to a personal space to retreat to at will.
To further improve morale, several cameras
will be placed along the outside perimeter of
the habitat. These cameras will feed into a
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4. NASA 3D Printed Habitat Challenge • August 2015
system of wall projectors that will give the
crew enhanced awareness of their surround-
ings. Additionally, a system involving a series
of lenses and optical fibers can bring in natural
light from outside into the habitat. Together,
these systems allow the habitat to forgo win-
dows, which would have to be brought from
Earth at the cost of substantial launch mass,
while taking into consideration the positive
psychological effects of not living completely
in a sealed cave-like environment. Also, lack-
ing windows, the habitat will be more resistant
to solar particle events.
To allow the crew to carry out their mis-
sion of science and exploration during their
stay, a large amount of space will be devoted to
laboratory and work areas. These are located
on the first tier of the habitat, near the airlock.
Crew entering the habitat after collecting sam-
ples will be able to quickly drop them off while
keeping as much dust as possible out of the
second and third tiers.
All three tiers will be filled with furniture
printed from composite basalt rod in the same
way as the frame. These elements will re-
quire little to no assembly and will not have
to be brought from Earth. This includes chairs,
couches, beds, desks, resistance exercise equip-
ment, storage boxes and more. A benefit of this
approach is that custom furniture and equip-
ment can continue to be printed outside the
habitat as needed and be brought in by the
crew. If the crews’ needs change during the
lengthy mission, equipment to satisfy that need
can be designed on Earth and sent to Mars in
a matter of hours. For example, basalt fibers
can be woven into a fabric for soft components,
and due to its low thermal conductivity, they
can be used in equipment requiring heat insu-
lation or low temperature control. In addition,
basalt fibers can be used as reinforcement in
any material.
The habitat’s critical life support equipment
will be housed in the spaces under the second
and third tiers. Each tier represents an eleva-
tion change of two feet. The volumes under-
neath will be reached for installation and main-
tenance by lifting the basalt composite plates
that form the floors. These spaces will also
serve to run the venting and electrical systems
throughout the habitat. Ventilation registers
will be located, as required, in the floor of the
hygiene, galley, and exercise facilities, as well
as the crew quarters. Similarly, fluid supplies
and drains will be made available in the galley,
lab and hygiene facilities. Electrical outlets will
be available throughout. Placing this equip-
ment under the floor will serve to reduce the
noise they generate significantly without the
need to build special sound baffling. The total
volume under all tiers combined will be ap-
proximately 50 m3, 22 m3 under the second
tier and 28 m3 under the third. This number
far exceeds the 4 m3 required to house all three
of the Environmental Control and Life Support
Systems. Unused volume in these areas will be
appropriated as additional storage space.
The habitat will be pressurized to 7.5 psi,
the minimum pressure required for long du-
ration habitation [4]. Low pressure has two
advantages. First, it serves to reduce the pre-
breathe time required when the crew transi-
tions from the habitat to their EVA suits. Sec-
ond, it reduces the stress to the structure of the
habitat from internal pressure.
The largest possible crew member suited
for EVA measures at 33.4 inches at their widest
point and 75.5 inches tall [4]. With this in mind,
all doors, walkways and ceilings have been de-
signed to exceed these dimensions to allow the
transit of a suited crew member through the
habitat. During a depressurization event, the
crew will be able to effect repairs to any part of
the habitat. The ceilings will be high to reduce
claustrophobic effects, but the specific height
should be determined nearer to the time of con-
struction to choose a height that is in style so as
to provide a pleasing aesthetic to the crew. The
specific details are not as important at the mo-
ment since the construction technique allows
for any height.
Renders of the habitat are shown in Fig-
ure 8.
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5. NASA 3D Printed Habitat Challenge • August 2015
IV. Site Selection
One of the key strengths of this proposed habi-
tat design is that it is location agnostic. The
habitat does not require any terrain type or fea-
tures not common to the majority of Martian
surface. Nevertheless, a landing site with ready
access to water ice, easily accessible basalt ore
deposits, and features of scientific interest are
desirable for this mission architecture.
With those considerations in mind the pro-
posed landing site is eastern Olympus Mons.
This site is among those put forward by the
Human Exploration of Mars Science Analy-
sis Group (HEM-SAG). This group presents
evidence which indicates the presence of lava
flows which would contain high concentra-
tions of basalt. They also show the presence
of fluvial channels, a geological feature of
intense scientific interest [5]. Additionally, im-
ages from the Mars Express HRSC have given
strong evidence of water rich glaciers at this
location which could be tapped during the
mission [6]. Finally, this landing site gives
the crew members the opportunity to visit the
the tallest mountain in the solar system. The
public appeal of NASA astronauts summiting
this peak would be immense.
As our planet’s closest neighbor, Mars has
long called to us. With the thrust of human
exploration now stretching out past the bound-
aries of our solar system, we at Red House are
inspired to answer that call. It is our hope that
this small red dot, which once seemed so far
out of reach, will soon join a pale blue one as
another home amongst the stars.
References
[1] Kunal Singha, "A Short Review on Basalt Fiber," International Journal of Textile Science 2012, no.
1(4): 19-28.
[2] M-H Y. Kim, et. al., "Development and testing of in situ materials for human exploration of Mars,"
High Performance Polymers 2000, no. 1(12): 13-26.
[3] M-H Y. Kim, et. al., "Comparison of Martian Meteorites and Martian Regolith as Shield Materials for
Galactic Cosmic Rays," NASA/TP-1998-208724.
[4] "Human Integration Design Handbook (HIDH)," NASA/SP-2010-3407.
[5] "Geology of Proposed Landing Sites for the Human Exploration of Mars," accessed July 31, 2015,
http://geology.wm.edu/bailey/mars/.
[6] J.W. Head, et. al., "Tropical to mid-latitude snow and ice accumulation, flow and glaciation on Mars,"
Nature 2005, no. 434, 346-351.
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6. NASA 3D Printed Habitat Challenge • August 2015
(a) (b)
Figure 1: a) Diagram of current mechanism for basalt fiber spinning [1]: 1. crushed stone silo, 2. loading
station, 3. transport system, 4. batch charging station, 5. initial melt zone, 6. secondary controlled heat
zone, 7. filament forming, 8. sizing applicator, 9. strand formation, 10. fiber tensioning, 11. winding. Such
a design can easily be modified for Mars applications, b) basalt composite rods
Figure 2: Conceptual drawing of a potential basalt deposition robot.
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7. NASA 3D Printed Habitat Challenge • August 2015
(a) (b)
Figure 3: a) CAD rendering of concept for structural basalt frame, b) close-up of cross-rods.
Figure 4: Cross-section of habitat displaying the different layers.
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8. NASA 3D Printed Habitat Challenge • August 2015
(a) (b)
(c)
Figure 5: a) Simplified wire frame with concrete anchor and lander airlock for supporting frame, b) Reflective
parachute layer for sealant backing and radiative heat loss reduction, c) Martian regolith layer for radiation
reduction. Images are composites of original images from habitat mockup and those sourced from NASA’s
rovers.
Figure 6: Method for constructing basalt plates [1]
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9. NASA 3D Printed Habitat Challenge • August 2015
Figure 7: Habitat floor plan
Figure 8: Habitat living space shown in perspective. Relative heights of first, second, and third tiers
displayed without perimeter walls, frame or furniture. CAD renders done in Solidworks.
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