An article written for the TMP2 Wiki project
(http://tmp2.wikia.com/wiki/Main_Page
) which I thought might be of some interest here. This article looks
at the possible forms of personal dwellings and buildings associated
with 'urban tree' structures featured in the proposed design of EvoHab
type habitats. These large on-orbit built-up habitat structures are
based on the use of a composite hull structure combining modular
pressure hull foundation and shielding panels attached to a spherical
enclosure space frame which then integrate to a polar 'core truss'
structure that passes through the interior center of the habitat and
is used as the primary attachment for functional elements both in the
exterior space and the interior pressurized environment. Elaborated by
secondary truss beam members and used as a conduit for infrastructure
and human traffic, this interior core truss would form the basis of
support for independent dwellings which retrofit to the outside of the
truss, expanding outward into the open volume of the habitat hull
which serves as an indoor 'exterior' space for the habitat. A key
feature of the EvoHab concept is the use of light and image
transmissive hull components which employ the outer surface of the
hull like a cellular heliostat array for light/image emitters on the
inner hull surface linked by fiber optics. (including in-line optical
filtering and high density photovoltaics to gain energy from unused IR
and UV portions of the ambient spectrum) In effect, the inner surface
of the hull becomes a virtual sky for the habitat, either providing
diffuse illumination with a simulation of a terrestrial sky and/or a
composite image of ambient space creating the illusion of a perfectly
transparent enclosure. This is an update of the original Asgard
habitat concept based on water-filled transparent hull systems as
proposed by Marshal T. Savage in the 1980s.

>

Urban Tree Housing Concepts

In this section we will explore various design concepts for the unique
microgravity housing of the Asgard habitats. We refer to this as Urban
Tree housing based on the basic architecture of EvoHab based habitats
featuring a large axial core truss with various branches to which the
functional elements of the habitat are attached. This tree-like truss
structure would provide the primary conduit of traffic and utilities
systems within the habitat while buildings and residence structures
would be attached on their exterior and accessed through the
interstitial spaces in the sides of the truss structure.

This structure would afford great potential variation in the form of
the individual functional structures or ‘buildings’ that attach to it,
supporting the full potential diversity of architecture found in any
terrestrial community. In smaller habitats, where the distance between
the core truss structure and the outer hull structure is relatively
small, the volume outside the core truss would tend to be treated
primarily as an interior space. For the personal dwelling in these
structures design would be focused entirely on the interior. However,
with the full-scale EvoHab the outer hull would be light-transmitting
and possibly image transmitting creating the illusion of a sky, making
the volume outside the core truss structure an ‘interior outside’
space into which the urban tree buildings project and which they use
as a view space. Thus for the dwellings in this space both interior
and exterior design would come into play in order to create an
aesthetically pleasing habitat and, in some cases, to facilitate human
access and activity in this large ‘outside’ microgravity volume. The
use of plants will also come into play here as a key means to
enhancing the aesthetic quality of the EvoHab environment and many of
the designs we will explore will feature plant cultivation technology
as integral to their structure, making the analogy of the urban tree
very literal indeed.

Dwellings in the Asgard habitat exist in a climate-controlled
environment and, being in microgravity, bear none of the structural
loads associated with conventional buildings. So the primary function
of architecture in this environment is the organization of space,
privacy, and sound insulation. Though smaller dwellings may be
designed as whole unit structures, most larger dwellings will be built-
up structures intended for quick assembly and disassembly and a high
degree of variability for functional adaptation and personalization.
This affords the use of very light materials and structures not
typically considered to have a structural role, such as textiles and
foams. In fact, textiles, foam, carbon fiber composite, cable,
aluminum, Velcro, and other ‘mechanical adhesives’ may be the primary
materials in most Asgard dwelling architecture. Surprisingly (and
rarely considered in most space habitat design), many simple organic
materials may also be employed, particularly sourced from grass plants
like reeds and bamboo as these would be potentially easy to cultivate
in a microgravity environment and easily used in woven materials or
wood-like composites. The classic paper screens of Japanese
architecture may find a new role in this architecture and even tatami
matting as an all-around wall covering! Transparent membrane materials
–elastomerics in particular– are also very likely as a low-mass
unbreakable alternative to glass windows, usually tensioned or
employing pressure rigidization. Though in general there will likely
be less need for glazed enclosures given the climate controlled
environment and these will more often be employed in the roll of
shades and screens or transparent protective barrier enclosures for
wet areas, clean-rooms, or industrial systems.

Let’s now consider some specific possible designs.

Capsule Cabins:
Capsule Cabins would have their origins in the Capsule Hotel units
common to this unique form of hotel accommodation first devised in
Japan to suit the needs of traveling businessmen. (these, in turn,
have their origins in railway ‘sleeper’ cabins of the early 20th
century which themselves may have originated with the enclosed beds of
Asia and medieval Europe) The original Capsule Hotel units were based
on fiberglass shells –usually two pieces–enclosing a bed and
surrounding the occupant with a collection of formed-in-place
accoutrements. These varied with design but typically included TV and
radio, air conditioning, a small writing shelf, lighting, and a number
of small storage compartments. Most were designed for entry through a
single small window/doorway at the foot-end of the capsule with the
units stacked several units high along a wall. In use to the present
day, more recent designs have been larger, allowing a person to sit up
fully in their space, affording more storage and larger appliances,
and based on side-door entry. This author has anticipated the likely
near-term evolution of these to 1.5x3m-4m units to accommodate the
increasing hassles of air travel and their adaptation into rigid-shell
cabins with a high degree of self-sufficiency for field deployment and
relief housing.

In microgravity such seemingly tiny spaces are comfortable and
functional –albeit still not suited to group occupancy– and have the
benefit of using more surfaces for formed-in accoutrements, since
there is no up or down and sleeping is done suspended or in a tube-
like hammock, freeing up ceiling and floor spaces to other uses. Thus
we arrive at the basic notion of the Capsule Cabin consisting of a
prismatic polygonal enclosure 1.5m wide, variable length, with door
and possibly window (or virtual window) at either end, and an
assortment of accoutrements built into its surrounding walls. This
space would be used in two common positions; a sprawled position where
the occupant is aligned parallel to the length of the space and a
‘seated’, ‘folded’, or ‘wedged’ position where one or more occupants
are in a position with torso roughly perpendicular to the length of
the space and possibly employing straps or wedging of buttocks and
feet to remain fixed to one interior face of the space –a position
used to perform some kinds of work or to engage in face-to-face
conversations. One surface wall of the cabin might be dedicated to
this position by featuring storage cabinets along its length with
recessed hinges and handles affording a flat ‘floor’ surface over
which some types of fold-out tables or shelves might be used.

The basic accoutrements of the Capsule Cabin would be very much akin
to that of the traditional Capsule Hotel unit but with some more high-
tech updates. A combination computer/communications/video display is
likely –designed for flat and fold-out positions in a number of
orientations– as well as some simple food preparation and cabin
cleaning systems. Early space habitats are likely to rely on shared
bathing and toilet facilities but this could be accommodated on the
personal level with the Capsule Cabin through the use of side-attached
‘wet units’ the inhabitant accesses through a side panel. In this same
way, multiple capsule rooms may be combined side-to-side to form
larger dwellings, most likely with dedicated sleeping or storage
areas. Sleeping would rely on simply drifting in the open cabin space
or the use of ‘sleeping socks’ that are strung diagonally between
sides of the cabin.

Early space habitats, which may rely on structures built whole on
Earth, are more likely to feature Capsule Cabins based on rigid
materials using retrofit paneling of softer surface materials. They
would tend to be very tightly integrated into the structure of a
prefabricated habitat. Built-up cabins, which are more likely with
Asgard development plans in general, would be deployable structures
based on foam and fabric materials rigidized by modular framing hidden
beneath the softer material surfaces. A capsule cabin may be
fabricated whole as a prefab of sorts, based on a primarily fabric
shell structure which then uses foam and frame inserts to rigidize it
much like a tent –an easy design concept to demonstrate on Earth.
Soundproofing would be a key factor in their design, given that they
would tend to be used in tight arrays. Generally, Capsule Cabins would
suit habitats with small hull volumes where they would be radial
arrayed in clusters around a central access corridor. Consequently,
like the original Capsule Hotel units, they would be single-sided,
lacking in any sort of exterior shell because their exterior sides are
completely hidden in their installation between hull and central
corridor. However, later designs for larger habitats may feature more
unified cabins with a smooth exterior enclosure surface over the back
of their formed-in features.

As one of the smallest of cabin designs, Capsule Cabins are likely to
be the basis of on-orbit emergency shelter designs, particularly for
community solar flare shelters and possibly employing a pressurized
shell structure with its own independent life support systems. The
basic form factor is also likely to see use a great variety of
applications based on enclosed or open-frame structures, including
industrial workstations, teleoperation stations, semi-automated
medical facilities, the ‘bridges’ of large spacecraft, and the basic
cabins of modest small passenger capacity utility spacecraft based on
‘beamship’ architectures.

Hutch Cabins:
Largely an evolution of the Capsule Cabin, the Hutch Cabin would be
based on taking two opposing faces of a Capsule Cabin and expanding
them into opposing planar surfaces over a larger area separated by a
gap of about 1.5 meters but with no particular limits in area –though
generally they would be within 4 meters square. Rectangular, circular,
or complex layouts would be possible. Side access doors would be the
norm but the cabins would also be suited to vertical stacking with a
central access port in the floor and/or ceiling. This arrangement has
the effect of forcing the assignment of a ‘floor’ surface used
predominately in a ‘folded’ or outstretched body position with back to
the floor or side walls and with radial arrangements of multiple
people. In a sense, one might refer to this as the ‘conversation pit’
of space dwellings, intended to make group use of a space more
convenient but also well suited in small sizes to the solitary
inhabitant in need of more flexible space.

Because this form compels the assignment of a floor plane and the use
of walls as back rests in a ‘wedged’ position, most accoutrements
would be designed for deployability from the floor and ceiling
surfaces rather than being simply ‘built-in’. Pop-up/down designs or
plug-in appliances would be likely. This would tend to produce a less
cluttered environment with less specialization of built-in features.
Sleeping arrangements could be free-floating or sleeping-sock based
but may also be ‘sleep pouch’ based where gently elasticized blankets
hold individuals to the floor surface.

This form factor supports a great variety of materials and layout
designs and one could expect to see an Asian influence in design and
the use of quite traditional materials like tatami matting for the
floor and ceiling surfaces. Large window areas are also possible with
this form, running along the narrow sides, though as a cost in side
seating surface. Radial arrangements around a core access corridor
like that used with Capsule Cabins would be quite practical, the hutch
cabins aligned with the narrow sides to the corridor, and Capsule
Cabin extensions would well integrate to the basic Hutch Cabin form
for various specialized rooms.

Hutch Cabins are likely to be one of the more common forms for large
Asgard habitat dwellings and so are more likely to feature self-
contained structure designs with a definite exterior aesthetic
treatment. They would also likely feature open exterior terraces along
perimeter edges or in circular ‘gazebos’ on top or bottom enclosed in
trellises that may double as plant cultivation systems.

Hutch Cabins would be well suited to group activities such as
conferences, classrooms, and media entertainment where individuals are
arranged radially and focus attention either inward, outward, or
toward the ceiling side for their shared activity. Larger launch
vehicles of the future are also likely to employ such cabin forms as
their cockpits –possibly simplifying future cockpit design to a single
control surface plane over a single flat or radially contoured foam
mattress.

Pod Cabins:
Based on the use of spherical room forms in clusters, this class of
microgravity structure would see the employ of some of the largest and
smallest of spaces in combination, this because while a sphere may be
one of the most efficient of closures for space, they are not
necessarily the most efficient spaces for the human body to move
around in under microgravity or the best form to array equipment
along. However, for the room of specialized purpose and single
occupancy, they offer one of the smallest efficient spaces and, when
combined with a concentric organization of surfaces, an efficient way
to limit spans in large volume structures to make them more functional.

The Pod Cabin shares some of the same perennial caveats of free-form
organic architecture on Earth and would solve them in similar ways,
primarily by the tight integration of fixtures and furnishings into
the enclosing form. For instance, the bedroom and bed furniture of the
organic design home are often one in the same, the structure
contiguous and ergonomically sculpted. Likewise, the bedroom itself is
an extension of another space, either by concentric hierarchy or
clustered network organization or a combination of the two –always
seeking to keep the span of spaces to within some comfortable human
scale like the spaces of a ant colony or animal warren. Pod Cabins
would employ this same strategy in a more volumetric way, since they
need provide no floor or stairs/ramps. They would employ numerous tiny
rooms of ergonomically specialized purpose, reducing them to a kind of
large appliance. And they would cluster them alternately in tight
‘knotted’ networks and spherically concentric surfaces with spans
between the surfaces limited. In other words, they would employ
complex forms very much akin to the hives of wild bees and wasps.

However, their scale would tend to be limited by the desire for light
and views and the placement of windows and open ‘balconies.’ A typical
small dwelling or one with a more sprawling form may be limited to
clusters of a relatively small number of rooms associated with one
larger lounge space or a common tubular network. A larger dwelling may
enclose such an inner ‘core’ cluster in a concentric outer volume
formed itself by a second outer cluster, the span between the two
clusters being the primary via and common lounge space. Higher degrees
of ‘nesting’ may be counterproductive.

Pod Cabins would likely rely heavily on the use of rigid and semi-
rigid variable density foam materials in combination with mechanical
adhesives. Typical structures would be almost entirely foam-based with
softer material at the surface, harder materials near the core and
around functional fixtures, various utilities bus routes tunneled
through them, the interior and exterior surfaces scored with a grid of
slots to host fabric paneling held in place by semi-rigid tension rods
and rings pressed into the panel slots. Their individual pod rooms
would be critically engineered in ergonomics and designed as whole
units in combination with any electrical, electronic, and mechanical
systems used with them. They may be sculpted whole with new processes
rather than being ‘deployable’ in the manner of other structures and
permanently joined together in custom combinations. They would be less
suited to the use of rigid alloy frame systems unless they can be
adapted to support modularity through rigid saddle-polyhedra module
systems.

Given the more advanced character of their design and fabrication,
large Pod Cabin dwellings are likely a later development, though small
all-in-one units may be likely early-on. Pod Cabin designs may see
increasing use with the evolution of progressively advanced fabber and
nanofabrication technology, ultimately becoming a ubiquitous form with
the advent of [[NanoFoam]] as it would suit that intelligent
material’s biomorphic fabrication processes.

Planar Halls:
An evolution of the Hutch Cabin and incorporating many of its design
concepts, Planar Halls are a likely form of larger microgravity
structure suited to large group facilities as well as individual
dwellings that parallel the ‘pavilion aesthetic’ of in-terrace
dwellings of Aquarian marine settlements. Planar Halls would be based
on large parallel planes separated by a 2 meter gap and linked by a
grid of hand-hold poles and columnar fixture ‘kiosks’. Each pair of
planes could form a ‘floor’ in a stacked structure with large volumes –
usually intended to enclose large machines or volumetric garden
atriums- created by profile ‘terracing’ of these stacked levels.

Planar Halls would likely be based on light planar truss structures
clad in modular paneling, allowing the volume of the planar trusses to
serve as a utilities route and back enclosure to flush-surface-mount
equipment. Primary columns formed on truss framing would be the main
structural supports while hand-hold poles would be placed at various
intervals and freely moved as needed. These poles, along with
additional primary framing, could double as supports for modular
partition walls, though these would also likely be fashioned as self-
contained modular units that may often include active systems –very-
much paralleling the design concepts of the T-slot based UtiliHab
structural system employed in Aquarian development.

Intended as ‘flex space’, the Planar Hall would employ most fixtures
in the form of columnar or enclosure plug-ins between the parallel
planes of the main structure and other plug-ins mounted to one side or
flush-mounted into the plane surfaces. Thus, many ways, the Planar
Hall parallels the concept of ‘open plan design’ in terrestrial
architecture. However, both planes would have potential as a ‘floor’,
partitioning could employ the creation of integral ‘horizontal’
Capsule and Hutch enclosures, and the usual human position when
traversing these spaces would likely be ‘diagonal’ except when in a
stationary position where handholds are used as anchoring points,
individuals using both handholds and an alternating ‘bounce’ between
the planes as the basis of locomotion. All modes of sleeping
arrangement would be usable.

A typical personal dwelling may be based on a single ‘floor’ pavilion
enclosed in elastomeric, fabric, or even paper screen window walls and
with functional areas based on a series of functional ‘islands’
installed between the planes. Soft cover paneling interspersed with
lighting would dominate most of the plane surface area –tatami matting
again an elegant aesthetic possibility for these spaces. Larger
‘buildings’ would employ numerous stacked floors or individual floors
of large planar areas, again organized around freely relocated
functional workstation ‘islands’. They would be particularly useful as
large community activity spaces such as workshops with numerous
machine workstations whose equipment and/or production line systems
need access from the sides, theaters or conference rooms where couch
seating can be plugged into the perimeters of an area of group focus
(a ‘stage’ space or display area), as well as ‘dance’ halls where the
planar surfaces host lighting and sound systems and support poles
would offer locations for people to ‘stand’ and perform their
microgravity dance moves. Large theater structures could be based on
atrium terracing where a large open central space is surrounded by
stacked Planar Hall space allowing for access from behind to balcony-
like theater seating using couch-like seats at the edge of the central
open space. This could afford the design of a kind of spherical
coliseum organized as a terraced central band capped by polar dome
framing supporting lighting and other systems. This is also a possible
organization for communal residential habitat structures that have not
yet achieved the volume suited to an Urban Tree organization and the
use of light transmitting [[EvoHab]] hull systems, the core truss of
the habitat hosting a volumetric garden and public facilities creating
a kind of central community atrium surrounded by stacked terrace
dwellings in combination with other cabin types along the hull wall.

Gazebos and other ‘Outdoor’ Structures:
The space habitat, of course, has no ‘exterior’ in the terrestrial
sense of the term. All space within the habitat is technically
‘interior’ with the distinction between interior and exterior space
within that space is a function of relative spans, lighting, and
hierarchy of enclosure. And large span space is generally of very poor
function in microgravity. Yet the apparent dichotomy between interior
and exterior and their social/cultural roles are important to the
human sense of comfort. Thus one can anticipate the use of
progressively large spans in progressively large volume habitat
structures as the basis of virtual exteriors providing ambient light
and large area views. The [[EvoHab]] concept and its employ of light/
image transmitting hull systems intended to create an impression of an
environment open to space itself is based on this premise. But the use
of such large span space presents many issues for their use, usually
relating to the hazard a lack of gravity presents when one is out of
reach of any handholds. The windows of terrestrial buildings make
little sense in the space habitat as there is no weather to provide a
light/view communicating barrier against. Yet there is a need to
confine the movement of human beings and their loose household
articles that precludes simply employing large open portals. In most
habitat dwellings translucent and transparent screens based on
fabrics, paper, and elastomerics are likely. But for the truly
‘outdoor’ spaces, such as balconies, terraces, and fully open
structures in the large space pace other strategies become necessary.

One likely strategy is the lattice or cage structure, which could be
seen as an analog to the traditional outdoor gazebo, bower, or
pergola. Using geometries with spans between 1 and 3 meters, these
structures would afford an open environment that would not seem cage-
like or confining yet provide enough density of hand-holds to afford a
sense of safety in the large span space. Lattice structures in
particular have the added potential to integrate a variety of fixtures
within their volume using the lattice structure as anchor points.
Tensioned fabric partitions, for instance, akin to the sailcloth
partitions used in many terrestrial outdoor structures. Seating in the
form of channel shaped benches and alcoves that accommodate a wedge
seating position. And also whole smaller cabin structures. An infinite
variety of fixtures could be attached to such structures and, given
the climate controlled nature of the habitat, could form the basis of
residential and work dwellings with a far more open aspect than the
more enclosed forms of cabins.

Given the likely strong desire of future space residents to employ
decorative plants as a means to ‘naturize’ the highly industrial
environment of the early space habitat, many novel systems for the
cultivation and integration of decorative plants into interior design
are likely. We will be discussing some of these systems in detail soon
but one of the most important may be the SkyGarden concept derived
from recent research into the use of semi-permeable ceramic pipes as
the basis of hydroponics systems. These systems combine plant support
with what is essentially a rigid structural element that can
potentially be formed into innumerable shapes. Simple systems are
likely to be based on single poles and narrow panels that may be
installed in the various forms of residential dwelling like a handhold
unit and feature their own integral lighting along with plant life
supports concealed within their bases. Expanding on this, we can
envision these being employed in greater number on the exterior of
dwellings, along terraces and in large arrays covering and concealing
exterior surfaces. As has been suggested previously, this could
ultimately be employed the make the analogy of the Urban Tree very
literal indeed.

Combine this technology with the gazebo and lattice structures
described above and one would have the basis of a large assortment of
very elegant outdoor structures that have the aspect of enormous
plants inside which one can reside like birds roosting in a tree.
These could be combined with the various forms of cabin structures or
be used with larger lattice spans as an enclosure around them, forming
a dwelling with a complex integration of indoor and garden outdoor
space suspended in the large microgravity volume of the habitat
macrostructure. It would seem likely that this combination could
become the definitive [[Asgard]] design vernacular.

Eric Hunting
erichunting@...