From Wikipedia, the free encyclopedia
Space architecture, in its simplest definition, is the theory and practice of designing and building
inhabited environments in
outer space.
The architectural approach to
spacecraft design addresses the total built environment. It is mainly based on the field of
engineering (especially
aerospace engineering), but also involves diverse disciplines such as
physiology,
psychology, and
sociology.
Like architecture on Earth, the attempt is to go beyond the component
elements and systems and gain a broad understanding of the issues that
affect design success. Much space architecture work has been in designing concepts for
orbital space stations and
lunar and
Martian exploration ships and surface bases for the world's space agencies, chiefly
NASA.
The practice of involving architects in the space program grew out of the
Space Race,
although its origins can be seen much earlier. The need for their
involvement stemmed from the push to extend space mission durations and
address the needs of astronauts including but beyond minimum survival
needs. Space architecture is currently represented in several
institutions. The
Sasakawa International Center for Space Architecture (SICSA) is an academic organization with the
University of Houston
that offers a Master of Science in Space Architecture. SICSA also
works design contracts with corporations and space agencies. In Europe,
International Space University is deeply involved in space architecture research. The
International Conference on Environmental Systems meets annually to present sessions on
human spaceflight and space
human factors. Within the
American Institute of Aeronautics and Astronautics,
the Space Architecture Technical Committee has been formed. Despite
the historical pattern of large government-led space projects and
university-level conceptual design, the advent of
space tourism threatens to shift the outlook for space architecture work.
Etymology
The word
space in space architecture is referring to the
outer space definition, which is from English
outer and
space.
Outer can be defined as "situated on or toward the outside; external; exterior" and originated around 1350–1400 in
Middle English.
Space is "an area, extent, expanse, lapse of time," the
aphetic of
Old French espace dating to 1300.
Espace is from
Latin spatium, "room, area, distance, stretch of time," and is of uncertain origin. In space architecture, speaking of
outer space
usually means the region of the universe outside Earth's atmosphere, as
opposed to outside the atmospheres of all terrestrial bodies. This
allows the term to include such domains as the lunar and Martian
surfaces.
Architecture, the concatenation of
architect and
-ure, dates to 1563, coming from
Middle French architecte. This term is of Latin origin, formerly
architectus, which came from
Greek arkhitekton.
Arkitekton means "master builder" and is from the combination of
arkhi- "chief" and
tekton "builder". The human experience is central to architecture – the primary difference between space architecture and
spacecraft engineering.
There is some debate over the terminology of space architecture.
Some consider the field to be a specialty within architecture that
applies architectural principles to space applications. Others such as
Ted Hall
of the University of Michigan see space architects as generalists, with
what is traditionally considered architecture (Earth-bound or
terrestrial architecture) being a subset of a broader space
architecture.
Any structures that fly in space will likely remain for some time
highly dependent on Earth-based infrastructure and personnel for
financing, development, construction, launch, and operation. Therefore,
it is a matter of discussion how much of these earthly assets are to be
considered part of space architecture. The technicalities of the term
space architecture are open to some level of interpretation.
Origins
Ideas of people traveling to space were first published in
science fiction stories, like Jules Verne's 1865
From the Earth to the Moon.
In this story several details of the mission (crew of three,
spacecraft dimensions, Florida launch site) bear striking similarity to
the
Apollo moon landings
that took place more than 100 years later. Verne's aluminum capsule
had shelves stocked with equipment needed for the journey such as a
collapsing telescope, pickaxes and shovels, firearms, oxygen generators,
and even trees to plant. A curved sofa was built into the floor and
walls and windows near the tip of the spacecraft were accessible by
ladder. The projectile was shaped like a bullet because it was
gun-launched
from the ground, a method infeasible for transporting man to space due
to the high acceleration forces produced. It would take
rocketry to get humans to the cosmos.
An illustration of von Braun's rotating space station concept
The first serious theoretical work published on space travel by means of rocket power was by
Konstantin Tsiolkovsky in 1903. Besides being the father of astronautics he conceived such ideas as the
space elevator (inspired by the Eiffel Tower), a rotating space station that created
artificial gravity along the outer circumference,
airlocks, space suits for
extra-vehicular activity (EVA), closed ecosystems to provide food and oxygen, and solar power in space.
Tsiolkovsky believed human occupation of space was the inevitable path
for our species. In 1952 Wernher von Braun published his own inhabited
space station concept in a series of magazine articles. His design was
an upgrade of earlier concepts, but he took the unique step in going
directly to the public with it. The
spinning space station
would have three decks and was to function as a navigational aid,
meteorological station, Earth observatory, military platform, and way
point for further exploration missions to outer space. It is said that
the space station depicted in
2001: A Space Odyssey
traces its design heritage to Von Braun's work. Wernher von Braun went
on to devise mission schemes to the Moon and Mars, each time publishing
his grand plans in
Collier's Weekly.
The flight of
Yuri Gagarin on April 12, 1961 was humanity's maiden
spaceflight.
While the mission was a necessary first step, Gagarin was more or less
confined to a chair with a small view port from which to observe the
cosmos – a far cry from the possibilities of life in space. Following
space missions gradually improved living conditions and quality of life
in
low Earth orbit.
Expanding room for movement, physical exercise regimens, sanitation
facilities, improved food quality, and recreational activities all
accompanied longer mission durations. Architectural involvement in
space was realized in 1968 when a group of architects and industrial
designers led by Raymond Loewy, over objections from engineers,
prevailed in convincing NASA to include an observation window in the
Skylab orbital laboratory.
This milestone represents the introduction of the human psychological
dimension to spacecraft design. Space architecture was born.
Theory
The subject of
architectural theory has much application in space architecture. Some considerations, though, will be unique to the space context.
Ideology of building
Louis Sullivan famously coined the phrase 'form ever follows function'
In the first century BC, the Roman architect
Vitruvius said all buildings should have three things: strength, utility, and beauty. Vitruvius's work
De Architectura,
the only surviving work on the subject from classical antiquity, would
have profound influence on architectural theory for thousands of years
to come. Even in space architecture these are some of the first things
we consider. However, the tremendous challenge of living in space has
led to habitat design based largely on functional necessity with little
or no applied
ornament. In this sense space architecture as we know it shares the
form follows function principle with
modern architecture.
Some theorists link different elements of the Vitruvian triad.
Walter Gropius writes:
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'Beauty'
is based on the perfect mastery of all the scientific, technological
and formal prerequisites of the task ... The approach of Functionalism means to design the objects organically on the basis of their own contemporary postulates, without any romantic embellishment or jesting.
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As space architecture continues to mature as a discipline, dialogue
on architectural design values will open up just as it has for Earth.
Analogs
A starting point for space architecture theory is the search for
extreme environments in terrestrial settings where humans have lived, and the formation of analogs between these environments and space. For example, humans have lived in submarines deep in the ocean, in bunkers beneath the Earth's surface, and on
Antarctica, and have safely entered burning buildings, radioactively contaminated zones, and the
stratosphere with the help of technology.
Aerial refueling enables
Air Force One to stay airborne virtually indefinitely. Nuclear powered submarines generate oxygen using
electrolysis and can stay submerged for months at a time. Many of these analogs can be very useful design references for space systems. In fact space station
life support systems
and astronaut survival gear for emergency landings bear striking
similarity to submarine life support systems and military pilot survival
kits, respectively.
Space missions, especially human ones, require extensive
preparation. In addition to terrestrial analogs providing design
insight, the analogous environments can serve as testbeds to further
develop technologies for space applications and train astronaut crews.
The
Flashline Mars Arctic Research Station is a simulated Mars base, maintained by the
Mars Society, on Canada's remote
Devon Island. The project aims to create conditions as similar as possible to a real
Mars mission and attempts to establish ideal crew size, test equipment
"in the field", and determine the best extra-vehicular activity suits
and procedures. To train for EVAs in
microgravity, space agencies make broad use of underwater and
simulator training. The
Neutral Buoyancy Laboratory,
NASA's underwater training facility, contains full-scale mockups of the
Space Shuttle cargo bay and International Space Station modules.
Technology development and astronaut training in space-analogous
environments are essential to making living in space possible.
In space
Fundamental
to space architecture is designing for physical and psychological
wellness in space. What often is taken for granted on Earth – air,
water, food, trash disposal – must be designed for in fastidious detail.
Rigorous exercise regimens are required to alleviate muscular atrophy
and other
effects of space on the body. That space missions are (optimally) fixed in duration can lead to
stress
from isolation. This problem is not unlike that faced in remote
research stations or military tours of duty, although non-standard
gravity conditions can exacerbate feelings of unfamiliarity and
homesickness. Furthermore, confinement in limited and unchanging
physical spaces appears to magnify interpersonal tensions in small crews
and contribute to other negative psychological effects.
These stresses can be mitigated by establishing regular contact with
family and friends on Earth, maintaining health, incorporating
recreational activities, and bringing along familiar items such as
photographs and green plants. The importance of these psychological measures can be appreciated in the 1968 Soviet 'DLB Lunar Base' design:
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...it
was planned that the units on the Moon would have a false window,
showing scenes of the Earth countryside that would change to correspond
with the season back in Moscow. The exercise bicycle was equipped with a
synchronized film projector, that allowed the cosmonaut to take a
'ride' out of Moscow with return.
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Mir
was a 'modular' space station. This approach allows a habitat to
function before assembly is complete and its design can be changed by
swapping modules.
The challenge of getting anything at all to space, due to launch
constraints, has had a profound effect on the physical shapes of space
architecture. All space habitats to date have used modular architecture
design. Payload fairing dimensions (typically the width but also the
height) of modern
launch vehicles
limit the size of rigid components launched into space. This approach
to building large scale structures in space involves launching multiple
modules separately and then manually assembling them afterward. Modular
architecture results in a layout similar to a tunnel system where
passage through several modules is often required to reach any
particular destination. It also tends to standardize the internal
diameter or width of pressurized rooms, with machinery and furniture
placed along the circumference. These types of space stations and
surface bases can generally only grow by adding additional modules in
one or more direction. Finding adequate working and living space is
often a major challenge with modular architecture. As a solution,
flexible furniture (collapsible tables, curtains on rails, deployable
beds) can be used to transform interiors for different functions and
change the partitioning between private and group space.
Eugène Viollet-le-Duc advocated different architectural forms for different materials.
This is especially important in space architecture. The mass
constraints with launching push engineers to find ever lighter materials
with adequate material properties. Moreover, challenges unique to the
orbital
space environment, such as rapid thermal expansion due to abrupt changes in solar exposure, and
corrosion
caused by particle and atomic oxygen bombardment, require unique
materials solutions. Just as the industrial age produced new materials
and opened up new architectural possibilities, advances in materials
technology will change the prospects of space architecture.
Carbon-fiber
is already being incorporated into space hardware because of its high
strength-to-weight ratio. Investigations are underway to see whether
carbon-fiber or other
composite materials
will be adopted for major structural components in space. The
architectural principle that champions using the most appropriate
materials and leaving their nature unadorned is called
truth to materials.
A notable difference between the orbital context of space
architecture and Earth-based architecture is that structures in orbit do
not need to support their own weight. This is possible because of the
microgravity condition of objects in free fall. In fact much space
hardware, such as the space shuttle's
robotic arm, is designed only to function in orbit and wouldn't be able to lift its own weight on the Earth's surface.
Microgravity also allows an astronaut to move an object of practically
any mass, albeit slowly, provided he or she is adequately constrained
to another object. Therefore, structural considerations for the orbital
environment are dramatically different from those of terrestrial
buildings, and the biggest challenge to holding a space station together
is usually launching and assembling the components intact. Construction
on extraterrestrial surfaces still needs to be designed to support its
own weight, but its weight will depend on the strength of the local
gravitational field.
Ground infrastructure
Human spaceflight currently requires a great deal of supporting
infrastructure on Earth. All human orbital missions to date have been
government-orchestrated. The organizational body that manages space
missions is typically a national
space agency, NASA in the case of the United States and
Roscosmos for Russia. These agencies are funded at the federal level. At NASA,
flight controllers
are responsible for real-time mission operations and work onsite at
NASA Centers. Most engineering development work involved with space
vehicles is
contracted-out to private companies, who in turn may employ
subcontractors of their own, while fundamental research and conceptual design is often done in
academia through
research funding.
Varieties
Suborbital
Structures that cross the
boundary of space but do not reach orbital speeds are considered
suborbital architecture. For
spaceplanes, the architecture has much in common with
airliner architecture, especially those of small
business jets.
Virgin Galactic
On June 21, 2004,
Mike Melvill reached space funded entirely by private means. The vehicle,
SpaceShipOne, was developed by
Scaled Composites as an experimental precursor to a privately operated fleet of
spaceplanes for
suborbital space tourism. The operational
spaceplane model, SpaceShipTwo (SS2), will be carried to an altitude of about 15 kilometers by a
B-29 Superfortress-sized carrier aircraft,
WhiteKnightTwo. From there SS2 will detach and fire its rocket motor to bring the craft to its
apogee
of approximately 110 kilometers. Because SS2 is not designed to go
into orbit around the Earth, it is an example of suborbital or
aerospace architecture.
The architecture of the SpaceShipTwo vehicle is somewhat
different from what is common in previous space vehicles. Unlike the
cluttered interiors with protruding machinery and many obscure switches
of previous vehicles, this cabin looks more like something out of
science fiction than a modern spacecraft. Both SS2 and the carrier
aircraft are being built from lightweight composite materials instead of
metal. When the time for weightlessness has arrived on a SS2 flight, the
rocket motor will be turned off, ending the noise and vibration. Passengers will be able to see the curvature of the Earth.
Numerous double-paned windows that encircle the cabin will offer views
in nearly all directions. Cushioned seats will recline flat into the
floor to maximize room for floating. An always-pressurized interior will be designed to eliminate the need for space suits.
Orbital
Orbital architecture is the architecture of structures designed to
orbit around the Earth or another
astronomical object. Examples of currently-operational orbital architecture are the
International Space Station and the re-entry vehicles
Space Shuttle,
Soyuz spacecraft, and
Shenzhou spacecraft. Historical craft include the
Mir space station,
Skylab, and the
Apollo spacecraft.
Orbital architecture usually addresses the condition of
weightlessness, a lack of atmospheric and magnetospheric protection from
solar and
cosmic radiation, rapid day/night cycles, and possibly risk of
orbital debris
collision. In addition, re-entry vehicles must also be adapted both to
weightlessness and to the high temperatures and accelerations
experienced during
atmospheric reentry.
International Space Station
The
International Space Station (ISS) is the only permanently inhabited
structure currently in space. It is the size of an American football
field and has a crew of six. With a living volume of 358 m³, it has
more interior room than the cargo beds of two American 18-wheeler
trucks.
However, because of the microgravity environment of the space station,
there are not always well-defined walls, floors, and ceilings and all
pressurized areas can be utilized as living and working space. The
International Space Station is still under construction. Modules were
primarily launched using the Space Shuttle until its deactivation and
were assembled by its crew with the help of the working crew on board
the space station. ISS modules were often designed and built to barely
fit inside the shuttle's payload bay, which is cylindrical with a 4.6
meter diameter.
Life aboard the space station is distinct from terrestrial life in
some very interesting ways. Astronauts commonly "float" objects to one
another; for example they will give a clipboard an initial nudge and it
will coast to its receiver across the room. In fact, an astronaut can
become so accustomed to this habit that they forget that it doesn't work
anymore when they return to Earth. The diet of ISS spacefarers is a combination of participating nations'
space food.
Each astronaut selects a personalized menu before flight. Many food
choices reflect the cultural differences of the astronauts, such as
bacon and eggs vs. fish products for breakfast (for the US and Russia,
respectively). More recently such delicacies as Japanense beef curry, kimchi, and swordfish (Riviera style) have been featured on the orbiting outpost. As much of ISS food is dehydrated or sealed in pouches
MRE-style, astronauts are quite excited to get relatively fresh food from shuttle and
Progress
resupply missions.
Food is stored in packages that facilitate eating
in microgravity by
keeping the food constrained to the table. Spent packaging and trash
must be collected to load into an available spacecraft for disposal.
Waste management
is not nearly as straight forward as it is on Earth. The ISS has many
windows for observing Earth and space, one of the astronauts' favorite
leisure activities. Since the Sun rises every 90 minutes, the windows
are covered at "night" to help maintain the 24-hour sleep cycle.
When a shuttle is operating in low Earth orbit, the ISS serves as a safety refuge in case of
emergency. The inability to fall back on the safety of the ISS during the latest
Hubble Space Telescope Servicing Mission (because of different orbital
inclinations)
was the reason a backup shuttle was summoned to the launch pad. So,
ISS astronauts operate with the mindset that they may be called upon to
give sanctuary to a shuttle crew should something happen to compromise a
mission. The International Space Station is a colossal cooperative
project between many nations. The prevailing atmosphere on board is one
of diversity and tolerance. This does not mean that it is perfectly
harmonious. Astronauts experience the same frustrations and
interpersonal quarrels as their Earth-based counterparts.
A typical day on the station might start with wakeup at 6:00am inside a private soundproof booth in the crew quarters.
Astronauts would probably find their sleeping bags in an upright
position tied to the wall, because orientation does not matter in space.
The astronaut's thighs would be lifted about 50 degrees off the
vertical. This is the
neutral body posture
in weightlessness – it would be excessively tiring to "sit" or "stand"
as is common on Earth. Crawling out of his booth, an astronaut may chat
with other astronauts about the day's science experiments, mission
control conferences, interviews with Earthlings, and perhaps even a
space walk or space shuttle arrival.
Bigelow Aerospace
Bigelow Aerospace
took the unique step in securing two patents NASA held from development
of the Transhab concept in regard to inflatable space structures. The
company now has sole rights to commercial development of the inflatable
module technology. On July 12, 2006 the
Genesis I experimental space habitat was launched into low Earth orbit.
Genesis I
demonstrated the basic viability of inflatable space structures, even
carrying a payload of life science experiments. The second module,
Genesis II, was launched into orbit on June 28, 2007 and tested out several improvements over its predecessor. Among these are
reaction wheel
assemblies, a precision measurement system for guidance, nine
additional cameras, improved gas control for module inflation, and an
improved on-board sensor suite.
While Bigelow architecture is still modular, the inflatable
configuration allows for much more interior volume than rigid modules.
The BA 330, Bigelow's full-scale production model, has more than twice
the volume of the largest module on the ISS. Inflatable modules can be
docked to rigid modules and are especially well suited for crew living
and working quarters. In 2009 NASA began considering attaching a
Bigelow module to the ISS, after abandoning the Transhab concept more
than a decade before.
The modules will likely have a solid inner core for structural
support. Surrounding usable space could be partitioned into different
rooms and floors. The
Bigelow Expandable Activity Module (BEAM) was transported to ISS arriving on April 10, 2016, inside the unpressurized cargo trunk of a
SpaceX Dragon during the
SpaceX CRS-8 cargo mission.
Bigelow Aerospace may choose to launch many of their modules
independently, leasing their use to a wide variety of companies,
organizations, and countries that can't afford their own space programs. Possible uses of this space include microgravity research and
space manufacturing.
Or we may see a private space hotel composed of numerous Bigelow
modules for rooms, observatories, or even a recreational padded
gymnasium. There is the option of using such modules for habitation
quarters on long-term space missions in the Solar System. One amazing
aspect of spaceflight is that once a craft leaves an atmosphere,
aerodynamic shape is a non-issue. For instance it's possible to apply a
Trans Lunar Injection
to an entire space station and send it to fly by the Moon. Bigelow has
expressed the possibility of their modules being modified for lunar and
Martian surface systems as well.
Lunar
Lunar architecture exists both in theory and in practice. Today the
archeological artifacts of temporary human outposts lay untouched on the surface of the Moon. Five
Apollo Lunar Module descent stages stand upright in various locations across the equatorial region of the
Near Side, hinting at the extraterrestrial endeavors of mankind. The leading hypothesis on the
origin of the Moon did not gain its current status until after lunar rock samples were analyzed.
The Moon is the furthest any humans have ever ventured from their
home, and space architecture is what kept them alive and allowed them to
function as humans.
Apollo
Lunar Module ascent stage blasts off the Moon in 1972, leaving the descent stage behind. View from TV camera on Lunar rover.
On the cruise to the Moon, Apollo astronauts had two "rooms" to choose from – the
Command Module (CM) or the Lunar Module (LM). This can be seen in the film
Apollo 13
where the three astronauts were forced to use the LM as an emergency
life boat. Passage between the two modules was possible through a
pressurized docking tunnel, a major advantage over the
Soviet design,
which required donning a spacesuit to switch modules. The Command
Module featured five windows made of three thick panes of glass. The
two inner panes, made of
aluminosilicate, ensured no cabin air leaked into space. The outer pane served as a debris shield and part of the heat shield needed for
atmospheric reentry.
The CM was a sophisticated spacecraft with all the systems required
for successful flight but with an interior volume of 6.17 m
3 could be considered cramped for three astronauts. It had its design weaknesses such as no
toilet (astronauts used much-hated 'relief tubes' and fecal bags). The coming of the
space station would bring effective life support systems with waste management and water reclamation technologies.
The Lunar Module had two stages. A pressurized upper stage,
termed the Ascent stage, was the first true spaceship as it could only
operate in the vacuum of space. The Descent stage carried the engine
used for descent, landing gear and radar, fuel and consumables,
the famous ladder, and the Lunar Rover during later Apollo missions.
The idea behind staging is to reduce mass later in a flight, and is the
same strategy used in an Earth-launched
multistage rocket.
The LM pilot stood up during the descent to the Moon. Landing was
achieved via automated control with a manual backup mode. There was no
airlock
on the LM so the entire cabin had to be evacuated (air vented to space)
in order to send an astronaut out to walk on the surface. To stay
alive, both astronauts in the LM would have to get in their
space suits
at this point. The Lunar Module worked well for what it was designed
to do. However, a big unknown remained throughout the design process –
the effects of
lunar dust. Every astronaut who walked on the Moon tracked in lunar dust, contaminating the LM and later the CM during
Lunar Orbit Rendezvous. These dust particles can't be brushed away in a vacuum, and have been described by
John Young of
Apollo 16
as being like tiny razor blades. It was soon realized that for humans
to live on the Moon, dust mitigation was one of many issues that had to
be taken seriously.
Project Constellation
NASA lunar outpost concepts under development
The
Exploration Systems Architecture Study that followed the
Vision for Space Exploration
of 2004 recommended the development of a new class of vehicles that
have similar capabilities to their Apollo predecessors with several key
differences. In part to retain some of the Space Shuttle program
workforce and ground infrastructure, the launch vehicles were to use
Shuttle-derived technologies. Secondly, rather than launching the crew and cargo on the same rocket, the smaller
Ares I was to launch the crew with the larger
Ares V to handle the heavier cargo. The two payloads were to
rendezvous in low Earth orbit
and then head to the Moon from there. The Apollo Lunar Module could
not carry enough fuel to reach the polar regions of the Moon but the
Altair lunar lander was intended to access any part of the Moon. While the Altair and surface systems would have been equally necessary for
Project Constellation to reach fruition, the focus was on developing the
Orion spacecraft to shorten the gap in US access to orbit following the retirement of the Space Shuttle in 2010.
Even NASA has described Constellation architecture as 'Apollo on steroids'. Nonetheless, a return to the proven
capsule design is a move welcomed by many.
The Orion Crew Module will have 2.5 times the interior volume of the
Apollo CM and will be able to carry up to six crew member to the ISS and
four to the Moon.
For Constellation, all astronauts were to have gone to the surface of
the Moon. As is standard practice for spacecraft, Orion will be equipped
with 'almost state of the art' technology. This strategy to reduce risk
by using proven technologies has been successfully demonstrated in
numerous
robotic missions. Accordingly, the CM will feature a
glass cockpit, automated docking, and a private unisex toilet. It will be constructed of a lightweight
aluminum lithium alloy and covered in a
Nomex felt-like layer for thermal protection. Like its Apollo predecessor Orion will have a
launch escape system, an
ablative heat shield for reentry, and
parachute recovery for water landing.
Martian
Martian architecture is architecture designed to sustain human life on the surface of
Mars, and all the supporting systems necessary to make this possible. The direct sampling of water ice on the surface, and evidence for geyser-like water flows within the last decade have made Mars the most likely extraterrestrial environment for finding liquid water, and therefore
alien life,
in the Solar System. Moreover, some geologic evidence suggests that
Mars could have been warm and wet on a global scale in its distant past.
Intense geologic activity has reshaped the surface of the Earth,
erasing evidence of our earliest history. Martian rocks can be even
older than Earth rocks, though, so exploring Mars may help us decipher
the story of our own geologic evolution including the
origin of life on Earth.
Mars has an atmosphere, though its surface pressure is less than 1% of
Earth's. Its surface gravity is about 38% of Earth's. Although a
human expedition to Mars has not yet taken place, there has been
significant work on Martian habitat design. Martian architecture
usually falls into one of two categories: architecture imported from
Earth fully assembled and architecture making use of local resources.
Von Braun and other early proposals
Wernher von Braun
was the first to come up with a technically comprehensive proposal for a
manned Mars expedition. Rather than a minimal mission profile like
Apollo, von Braun envisioned a crew of 70 astronauts aboard a fleet of
ten massive spacecraft. Each vessel would be constructed in low Earth
orbit, requiring nearly 100 separate launches before one was fully
assembled. Seven of the spacecraft would be for crew while three were
designated as cargo ships. There were even designs for small "boats" to
shuttle crew and supplies between ships during the cruise to the Red
Planet, which was to follow a minimum-energy
Hohmann transfer
trajectory. This mission plan would involve one-way transit times on
the order of eight months and a long stay at Mars, creating the need for
long-term living accommodations in space. Upon arrival at the Red
Planet, the fleet would brake into Mars orbit and would remain there
until the seven human vessels were ready to return to Earth. Only
landing
gliders,
which were stored in the cargo ships, and their associated ascent
stages would travel to the surface. Inflatable habitats would be
constructed on the surface along with a landing strip to facilitate
further glider landings. All necessary propellant and consumables were
to be brought from Earth in von Braun's proposal. Some crew remained in
the passenger ships during the mission for orbit-based observation of
Mars and to maintain the ships.
The passenger ships had habitation spheres 20 meters in diameter.
Because the average crew member would spend much time in these ships
(around 16 months of transit plus rotating shifts in Mars orbit),
habitat design for the ships was an integral part of this mission.
Von Braun was aware of the threat posed by extended exposure to
weightlessness. He suggested either tethering passenger ships together
to spin about a common center of mass or including self-rotating,
dumbbell-shaped "gravity cells" to drift alongside the flotilla to
provide each crew member with a few hours of artificial gravity each
day. At the time of von Braun's proposal, little was known of the dangers of
solar radiation beyond Earth and it was
cosmic radiation that was thought to present the more formidable challenge. The discovery of the
Van Allen belts
in 1958 demonstrated that the Earth was shielded from high energy solar
particles. For the surface portion of the mission, inflatable habitats
suggest the desire to maximize living space. It is clear von Braun
considered the members of the expedition part of a community with much
traffic and interaction between vessels.
The Soviet Union conducted studies of human exploration of Mars
and came up with slightly less epic mission designs (though not short on
exotic technologies) in 1960 and 1969. The first of which used
electric propulsion for interplanetary transit and
nuclear reactors
as the power plants. On spacecraft that combine human crew and nuclear
reactors, the reactor is usually placed at a maximum distance from the
crew quarters, often at the end of a long pole, for radiation safety.
An interesting component of the 1960 mission was the surface
architecture. A "train" with wheels for rough terrain was to be
assembled of landed research modules, one of which was a crew cabin.
The train was to traverse the surface of Mars from south pole to north
pole, an extremely ambitious goal even by today's standards. Other Soviet plans such as the
TMK
eschewed the large costs associated with landing on the Martian surface
and advocated piloted (manned) flybys of Mars. Flyby missions, like
the lunar
Apollo 8,
extend the human presence to other worlds with less risk than landings.
Most early Soviet proposals called for launches using the ill-fated
N1 rocket. They also usually involved fewer crew than their American counterparts.
Early Martian architecture concepts generally featured assembly in low
Earth orbit, bringing all needed consumables from Earth, and designated
work vs. living areas. The modern outlook on Mars exploration is not
the same.
Recent initiatives
In
every serious study of what it would take to land humans on Mars, keep
them alive, and then return them to Earth, the total mass required for
the mission is simply stunning. The problem lies in that to launch the
amount of consumables (oxygen, food and water) even a small crew would
go through during a multi-year Mars mission, it would take a very large
rocket with the vast majority of its own mass being propellant. This is
where multiple launches and assembly in Earth orbit come from. However
even if such a ship stocked full of goods could be put together in
orbit, it would need an additional (large) supply of propellant to send
it to Mars. The
delta-v, or change in velocity, required to insert a spacecraft from Earth orbit to a Mars
transfer orbit
is many kilometers per second. When we think of getting astronauts to
the surface of Mars and back home we quickly realize that an enormous
amount of propellant is needed if everything is taken from the Earth.
This was the conclusion reached in the 1989 '90-Day Study' initiated by
NASA in response to the
Space Exploration Initiative.
Several techniques have changed the outlook on Mars exploration. The
most powerful of which is in-situ resource utilization. Using hydrogen
imported from Earth and carbon dioxide from the Martian atmosphere, the
Sabatier reaction can be used to manufacture
methane (for rocket propellant) and water (for drinking and for oxygen production through
electrolysis). Another technique to reduce Earth-brought propellant requirements is
aerobraking.
Aerobraking involves skimming the upper layers of an atmosphere, over
many passes, to slow a spacecraft down. It's a time-intensive process
that shows most promise in slowing down cargo shipments of food and
supplies. NASA's
Constellation program
does call for landing humans on Mars after a permanent base on the Moon
is demonstrated, but details of the base architecture are far from
established. It is likely that the first permanent settlement will
consist of consecutive crews landing prefabricated habitat modules in
the same location and linking them together to form a base.
In some of these modern, economy models of the Mars mission, we
see the crew size reduced to a minimal 4 or 6. Such a loss in variety
of social relationships can lead to challenges in forming balanced
social responses and forming a complete sense of identity.
It follows that if long-duration missions are to be carried out with
very small crews, then intelligent selection of crew is of primary
importance. Role assignments is another open issue in Mars mission
planning. The primary role of 'pilot' is obsolete when landing takes
only a few minutes of a mission lasting hundreds of days, and when that
landing will be automated anyway. Assignment of roles will depend
heavily on the work to be done on the surface and will require
astronauts to assume multiple responsibilities. As for surface
architecture inflatable habitats, perhaps even provided by
Bigelow Aerospace, remain a possible option for maximizing living space. In later missions, bricks could be made from a
Martian regolith mixture for shielding or even primary, airtight structural components. The environment on Mars offers different opportunities for
space suit design, even something like the skin-tight
Bio-Suit.
A number of specific habitat design proposals have been put
forward, to varying degrees of architectural and engineering analysis.
One recent proposal—and the winner of NASA's 2015 Mars Habitat
Competition—is
Mars Ice House. The design concept is for a Mars surface habitat,
3d-printed
in layers out of water ice on the interior of an Earth-manufactured
inflatable pressure-retention membrane. The completed structure would
be semi-transparent, absorbing
harmful radiation in several wavelengths, while admitting approximately 50 percent of light in the
visible spectrum. The habitat is proposed to be entirely set up and built from an
autonomous robotic
spacecraft and bots, although human habitation with approximately 2–4
inhabitants is envisioned once the habitat is fully built and tested.
Robotic
It is
widely accepted that robotic reconnaissance and trail-blazer missions
will precede human exploration of other worlds. Making an informed
decision on which specific destinations warrant sending human explorers
requires more data than what the best Earth-based telescopes can
provide. For example, landing site selection for the Apollo landings
drew on data from three different robotic programs: the
Ranger program, the
Lunar Orbiter program, and the
Surveyor program.
Before a human was sent, robotic spacecraft mapped the lunar surface,
proved the feasibility of soft landings, filmed the terrain up close
with television cameras, and scooped and analysed the soil.
A robotic exploration mission is generally designed to carry a
wide variety of scientific instruments, ranging from cameras sensitive
to particular wavelengths, telescopes,
spectrometers,
radar devices,
accelerometers,
radiometers,
and particle detectors to name a few. The function of these
instruments is usually to return scientific data but it can also be to
give an intuitive "feel" of the state of the spacecraft, allowing a
subconscious familiarization with the territory being explored, through
telepresence. A good example of this is the inclusion of
HDTV cameras on the Japanese lunar orbiter
SELENE.
While purely scientific instruments could have been brought in their
stead, these cameras allow the use of an innate sense to perceive the
exploration of the Moon.
The modern, balanced approach to exploring an extraterrestrial
destination involves several phases of exploration, each of which needs
to produce rationale for progressing to the next phase. The phase
immediately preceding human exploration can be described as
anthropocentric sensing, that is, sensing designed to give humans as
realistic a feeling as possible of actually exploring in person. More,
the line between a human system and a robotic system in space is not
always going to be clear. As a general rule, the more formidable the
environment, the more essential robotic technology is. Robotic systems
can be broadly considered part of space architecture when their purpose
is to facilitate the habitation of space or extend the range of the
physiological
senses into space.
Future
The future of space architecture hinges on the
colonization of space. Under the historical model of government-orchestrated exploration missions initiated by single
political administrations,
space structures are likely to be limited to small-scale habitats and
orbital modules with design life cycles of only several years or
decades. The designs, and thus architecture, will generally be fixed
and without real time feedback from the spacefarers themselves. The
technology to repair and upgrade existing habitats, a practice
widespread on Earth, is not likely to be developed under short term
exploration goals. If exploration takes on a multi-administration or
international character, the prospects for space architecture
development by the inhabitants themselves will be broader. Private
space tourism
is a way the development of space and a space transportation
infrastructure can be accelerated. Virgin Galactic has indicated plans
for an orbital craft,
SpaceShipThree. The demand for space tourism is one without bound. It is not difficult to imagine lunar parks or cruises by
Venus. Another impetus to become a spacefaring species is
planetary defense.
The classic space mission is the Earth-colliding
asteroid interception mission. Using
nuclear detonations
to split or deflect the asteroid is risky at best. Such a tactic could
actually make the problem worse by increasing the amount of asteroid
fragments that do end up hitting the Earth.
Robert Zubrin writes:
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If
bombs are to be used as asteroid deflectors, they cannot just be
launched willy-nilly. No, before any bombs are detonated, the asteroid
will have to be thoroughly explored, its geology assessed, and
subsurface bomb placements carefully determined and precisely located on
the basis of such knowledge. A human crew, consisting of surveyors,
geologists, miners, drillers, and demolition experts, will be needed on
the scene to do the job right.
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Robotic probes have explored much of the solar system but humans have not yet left the Earth's influence
If such a crew is to be summoned to a distant asteroid, there may be less risky ways to divert the asteroid. Another promising
asteroid mitigation strategy
is to land a crew on the asteroid well ahead of its impact date and to
begin diverting some its mass into space to slowly alter its trajectory.
This is a form of rocket propulsion by virtue of
Newton's third law
with the asteroid's mass as the propellant. Whether exploding nuclear
weapons or diversion of mass is used, a sizable human crew may need to
be sent into space for many months if not years to accomplish this
mission. Questions such as what the astronauts will live in and what the ship will be like are questions for the space architect.
When motivations to go into space are realized, work on
mitigating the most serious threats can begin. One of the biggest
threats to astronaut safety in space is sudden radiation events from
solar flares.
The violent solar storm of August 1972, which occurred between the
Apollo 16 and Apollo 17 missions, could have produced fatal consequences
had astronauts been caught exposed on the lunar surface.
The best known protection against radiation in space is shielding; an
especially effective shield is water contained in large tanks
surrounding the astronauts.
Unfortunately water has a mass of 1000 kilograms per cubic meter. A
more practical approach would be to construct solar "storm shelters"
that spacefarers can retreat to during peak events. For this to work, however, there would need to be a
space weather broadcasting system in place to warn astronauts of upcoming storms, much like a
tsunami warning system
warns coastal inhabitants of impending danger. Perhaps one day a fleet
of robotic spacecraft will orbit close to the Sun, monitoring solar
activity and sending precious minutes of warning before waves of
dangerous particles arrive at inhabited regions of space.
Nobody knows what the long-term human future in space will be.
Perhaps after gaining experience with routine spaceflight by exploring
different worlds in the Solar System and deflecting a few asteroids, the
possibility of constructing non-modular space habitats and
infrastructure will be within capability. Such possibilities include
mass drivers on the Moon, which launch payloads into space using only electricity, and spinning space colonies with
closed ecological systems. A Mars in the early stages of
terraformation,
where inhabitants only need simple oxygen masks to walk out on the
surface, may be seen. In any case, such futures require space
architecture.
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