IV. Habitability

Habitabilityrefers to making life onboard �ther as acceptable to the inhabitants aseconomically possible.� With permanentresidency on �ther being considered, it is not prudent to always opt for lowcost and ignore habitability.� Permanentresidents of space will not accept the relatively primitive conditions thatexist today onboard space flights.� In�ther, the emphasis must be on providing an environment that a person would behappy, healthy, and successful in family life, work, and communityrelationships.� Negative emotions suchas anger, fear, envy, loneliness, or greed must be prevented as much aspossible through design.� The three mainannoyances in current spacecraft that detract from habitability are low levelsof environmental comfort, personal inconveniences, and a lack of personalcontrol over their environments [ref 13].

IV.A Basic Habitability Aspects

����������� Basichabitability aspects are as follows: climate, illumination, colors andsurfaces, d�cor, vibration, odor, noise, pests, interior space/layout, hygiene,and food and drink [ref 1].� Althoughsome of these components alone may seem insignificant, when combined theydetermine the quality of life onboard �ther and ultimately will be a key factorin whether or not colonization of space is successful.

IV.A.1 Climate

Maintaining acomfortable �shirt-sleeve� environment is key to having a vibrant, productivecolony.� Studies have demonstrated areduction in cognitive and psychomotor performance at and above a temperatureof 302 K (~30˚ C, ~85˚ F) [ref 14].Performance also suffers if the temperature is below 291 K and thedecrease in performance is proportional to the length of exposure.� Therefore, the CELSS must provide anenvironment between 291-300 K and 25 � 70% relative humidity.

IV.A.2 Illumination

Illumination isvital for visibility within �ther.� NASAstandards advise that �bright and uniform� wide-spectrum light should beemployed in work areas; nighttime and social activities could just utilize warmwhite light, this would also serve to help the average human�s association of�warm� light with such activities [ref 13, 14].� Natural lighting via the windows could serve the purpose of widespectrum light.� Windows and/or viewingpanels are important for satisfying curiosity and orienting the colonists totheir external environments and should be integrated into the exterior designof �ther.� However, sharp differences inlighting between adjacent areas should be avoided to reduce the difficulty ofadjusting.� Special care must also betaken when viewing objects through a window, as bright objects and glares aredetrimental to eyesight.� Simulating14-hour days and 10-hour nights would also be required in a colony thatreceives 24-hour sunlight.

IV.A.3 Colors and Surfaces

Colors andsurfaces provide a sense of aesthetics but also can be very useful innavigation throughout the colony.Colors are especially important in micro-gravity areas where directionsof �up� and �down� are not absolute.Painting the �ceiling� a different color from the �floor� could helpworkers easily orient themselves in micro-gravity work areas.

IV.A.4 D�cor

D�cor such asart helps people adapt to monotonous environments, and pictures of earthlandscapes could educate children born in space about earth.� Flexible d�cor such as movable partitions,removable wall covers, etc. give colonists a sense of personal control as wellas adding variety.� A resident artistprogram will also be established to ensure the diffusion and advancement of allvisual arts.

IV.A.5 Vibration

Elimination ofvibration is important for health and comfort of the colonists.�� Ways that vibration can be transmitted tothe body is through the hands (known as hand-arm vibration or HAV) and throughthe seat or feet (known as whole body vibration or WBV).� Exposure to HAV can cause negative healtheffects that are collectively called hand-arm vibration syndrome.� Health effects include vibration whitefinger, which is the lack blood supply to the fingers and can cause uncomfortableand sometimes painful spasms [ref 15].Various frequencies of WBV have different effects on health, back painoccurs at 4-12 Hz; WBV of 4-5 Hz causes digestive diseases; and frequenciesbelow 20 Hz instigate cardiovascular disorders [ref 16].� Discomfort from vibrations is most common inthe form of kinetosis (motion sickness), which is at its worst with frequenciesof 0.125-0.25 Hz.� Vibration measurementsystems consisting of a transducer to sense the vibration; an amplifyingdevice; a frequency weighing filter which accounts for variations in humanresponse to different frequencies; a data recorder; and a signal analyzer,should prove to be of use in determining what preventative measures areneeded.� Such measures include limitingthe time spent by workers in a vibrating environment, mechanically isolatingthe source of vibration, maintaining machinery to minimize vibrations, andinstalling vibration-damping insulation [ref 15, 16].

IV.A.6 Odor

Odors canaccumulate rapidly when air is recycled, fortunately people adapt to increasingconcentrations of odors quite well.However, toxic substances, whether pleasant smelling or not, must bekept below unacceptable levels.� Also,obnoxious odors must be controlled to minimize distraction and dissatisfaction.� Most odors originate from hygiene and bodilyfunctions; to counter hygienic odors colonists must be able to wash themselvesat least once a week and change into fresh cloths at least twice a week.� Electrostatic ionization, dry scrubbing,chemical bed filtration, and ultraviolet radiation are all methods that canreduce odor onboard �ther.� Chemical bedfiltration removes solid pollutants from the air, electrostatic ionizationremoves large particles, dry scrubbing reacts unwanted gasses or vapors with asorbent bed, and UV radiation destroys germs that produce odors [ref 13].

IV.A.7 Noise

Sources ofambient noise onboard �ther will be pumps, fans, transportation infrastructureand other equipment.� This ambient noisecould potentially become an annoyance and interfere with speech and sleep ifnot properly controlled.� Ultimately,noise can cause aggressive behavior.Several methods can achieve the design goal of less than 35 dB forresidential areas of �ther, and a higher limit of 55 dB for work areas.� Soundproofing will be especially importantin high-density apartments, where a sense of privacy is needed.� Soundproofing methods include: increasingmass, which adds inertia to walls and prevents excitation; decouplingcontiguous building elements, thereby prevents transmission of sound; insertingabsorbent material converts and dissipates acoustic energy; using sealant, thusthwarting the passage of sound through gaps and cracks; and includingviscoelastic materials to help deaden sound [ref 17].� Where unwanted sound is continuous or highly repetitious, activesound cancellation may be considered.

IV.A.8 Pests

����������� Weas human beings despise pests for many good reasons; pests commonly are thecarriers of deadly disease, cause great discomfort, and are also associatedwith low standards of living.� Commonpests of home, people, and pets found on earth include ants, bed bugs, bees andwasps, recluse spiders, carpenter bees, carpet beetles, cliff swallows, clothesmoths, cockroaches, conenose bugs, delusory parasitoids, fleas, head lice, hobospiders, horsehair worms, house flies, house mice, mosquitoes, pantry pests,silverfish and firebrats, stable flies, termites, ticks, windscorpions, andwood-boring beetles [ref 36].

Immigrants willbe screened for pests, and active control will be undertaken.� In spite of this, the possibility of pestsand/or their eggs reaching �ther still exists.Since the most common form of pest control, pesticides, would behazardous to use onboard �ther, other forms of pest control, such as baits andtraps should be considered.� They arealso considered to be more effective in controlling pests since the prolongeduse of pesticides leads to an increased frequency in pest population ofpesticide-resistant members [ref 33].Forms of natural control include using parasitoids, predators,pathogens, and weed feeders to destroy pests [ref 35].

Parasitoids developinside of and eventually kill their hosts, and they are dissimilar in theirchoice of hosts; thus different species of parasitoids must be imported tocombat different species of pests.However, the concern that some parasitoids may be considered peststhemselves limits the effectiveness of parasitoid pest-control.� Despite that concern, many species ofparasitoids would not be considered pests and could potentially be used as pestcontrol, such as wasps, of the Anaphes flavipes, Bathyplectes anurus andB. curculionis, Catolaccus grandis, Cotesia glomerata, Diadegmainsulare, Encarsia formosa, Encarsia inaron, Eretmoceruscalifornicus, Eriborus terebrans, Lysiphlebus testaceipes, Metaphycusalberti, Muscidifurax raptor, Nealiolus curculionis, Peristenusdigoneutis, Pholetesor ornigis, Trichogramma ostriniae, and Trissolcusbasalis species; and flies of the Pseudacteon spp. and Trichopodapennipes species [ref 35].� Most ofthe parasitoids would be used in the agriculture areas, where they would be ofgreat help in reducing the population of crop pests such as the cornborer, thecabbageworm, and the boll weevil.Although the environment inside the agriculture sections consists mainlyof plant growing machinery and hydroponics equipment and will naturally notsupport many pests, the probability that pests will infect communal growingareas which do not use hydroponics is high, since many pests, their eggs, andtheir offspring are small and easily hidden by natural habitat.

Predatorsconsume their nonspecific prey and thus can be used to control a wide varietyof pests, mostly crop pests.� Theyinclude beetles and lady beetles of the Chilocorus kuwanae, Chilocorusstigma, Coccinella septempunctata, Coleomegilla maculata, Cryptolaemusmontrouzieri, Harmonia axyridis, Hippodamia convergens, Pseudoscymnustsugae, Rodolia cardinalis, Stethorus punctum, Lebiagrandis, and Aleochara bilineatis species; bugs of the Campylommaverbasci, Deraeocoris nebulosus, Geocoris spp., Orius spp.,and Podisus maculiventris species; lacewings of the Chrysoperlacarnea/Chrysoperla rufilabris and Hemerobius spp. species;midges of the Aphidoletes aphidimyza species; mites of the Galendromus� occidentalis, Galendromus� pyri, Neoseiulus� fallacies, Zetzellia mali, Euseiustularensis, and Phytoseiulus persimilis species; and harvestmen ofthe Phalangium opilio species [ref 35].While predators may play a limited role in the containment of pests,they would serve as a major educational and physical link back to earth, andchildren born in �ther would still be able to identify themselves with theirancestors even though they live in space.

Beneficialpathogens and antagonists aid humans by infecting and suppressing harmful pests[ref 35].� The term pathogen usuallyrefers to a bacteria, virus, or fungi that infects harmful insects or mites,while the term antagonist refers to a microorganism that is helpful in the controlof microorganisms that cause food spoilage and plant disease [ref 35].� Pathogens, like parasitoids, are speciesspecific in their selection of hosts, but both pathogens and antagonists can beinserted into solutions that can be sprayed [ref 35].� Antagonists will probably be used the most since they, whenincorporated into waxes and other coatings, can effectively inhibit foodspoilage.� Pathogens to be used onboard�ther would include viruses, bacteria, fungi, nematodes, protozoa, and algae,while antagonists to be used would include the species of Ampelomycesquisqualis, Phanerochaetegigantea, Pseudomonas syringae, and Trichoderma spp. [ref35].

Weeds thatreached �ther would quickly propagate and cover much of the arable landscapeinside, since there would be little to no preexisting methods to control thoseweeds.� To offset this effect, naturalenemies of weeds should be imported to �ther.Weed feeders include moths, fungi, weevils, beetles, and flies.� However, their effectiveness may be limitedby parasitoids and predators, which may also prey on weed feeders.

IV.A.9 Interior Space/Layout

����������� Spacefor colonists must be adequate for their needs yet not so much as to beredundant and unnecessary.� Space forCELSS machinery, recreational and social functions, living habitats,communications infrastructure, transportation, agriculture, storage, andbusinesses must be provided for [ref 34].While some space needs are unique, many based on communal activities, suchas assembly space, share common elements with other needs.� Thus, a space designed for assembly could besimultaneously used for a mosque, a church, and a community hall.� Hopefully, instead of having tensions arisefrom shared use, it is hoped that the different elements of �ther will be bondedcloser together because of this sharing.Recreational areas are needed for housing the recreational activitiesthat will be available to the colonists, their importance is discussed later.� Open spaces with grass, trees, and possiblysome recreational areas, on the other hand, if placed next to high-densityregions provide a release from the pressure of other people, and also diminishthe sense of living in a manmade object [ref 34].� They can alleviate the sense of artificiality that arises whenpeople are placed into created environments.Introduction of pets that colonists can grow or take care of would alsohelp create a sense of control as well as maintaining a visible connectionbetween the colonists and earth.� Thedesign and construction of habitats should closely adhere to privacy andpersonal aesthetics goals set forth by the individuals who will eventuallyreside in those habitats.� Thus, it mustfollow that a very flexible but fast method of construction must be employed,which could give rise to many different types of dwellings [ref 34].� Such a system could be achieved by usingmodular parts, which can provide a wide variety of combinations.� The structure would be made out of metalbeam components, while panels fashioned out of lunar slag and with decorativecoverings would provide soundproofing and fire deterrence.

����������� Thespace needs inside the torus can be summarized in the following table.

While the total figure of 1.37x10⁷m² clearly exceeds the total area available on the primary floor ofthe torus, it should be noted that the torus also contains a lower level thatwould house most of the agriculture and food processing space and that mostbuildings in �ther will be multi-story, thus creating out of a piece of landtwo, three, or four times the original amount of space.

IV.A.10 Hygiene

����������� Hygienewater has the potential to place a high strain on the CELSS, particularly thewater management subsystem.� Hopefullythe majority of colonists will be able to maintain an acceptable level ofhygiene while not using an excessive amount of water.� Toilets in the residential areas will be similar to those onearth for maximum ease and comfort, but those in the microgravity environmentof the work areas will have to be highly reliable and not suffer the mechanicaldifficulties of the integrated fecal/urine collector onboard the spaceshuttle.� Showers should be efficient aspossible, thus the use of graywater heat recovery systems is warranted.� In such a system, the exiting wastewatertransfers some of its heat to the incoming cold water, thus reducing the energyload on the water heater.� Graywaterheat recovery systems could also be implemented in other areas where hot wateris needed.

IV.A.1 Food

����������� Foodis an essential part of daily living, as it not only fulfills physical needsbut also psychological and social needs.Shared meals help create unity between colonists and food serves as aform of recreation in boring environments.For example, good food is a major motivation for sailors in submarinesand remote Antarctic research bases [ref 13]. Thus it is important for food aboard�ther to not only be nutritious but also to be delicious.� However, due to the restrictions of theCELSS, most meals will be heavy on cereals and vegetables.� Further discussion of this issue can befound in the CELSS section.� Consumingalcoholic beverages are a common recreational pastime in the US, it also causesmany problems if the consumer becomes inebriated.� However, it also serves as a powerful motivator for somepeople.� The allowance of alcohol on�ther will have to be seriously considered, and although current NASA policiesno alcohol to be available during space missions, to some careful consumptionof alcohol is seen as a valid way of releasing stress [ref 13].

IV.B Long Term Habitability Aspects

����������� Long-term habitability aspects are as follows: crewcomposition, health care, communication, privacy, and entertainment [ref1].� They become important whenconsidering extended periods of residency.

IV.B.1 Crew Composition

����������� Crewcomposition will be important in long-term missions because colonists must beable to work together.� However, debateover whether colonists should be selected on a �first come, first serve� basisor on a merit basis arose.� While theselection of colonists should not be exclusive, unwanted elements of societysuch as criminals should not be allowed onto �ther.� A combination of these two selection processes was finallychosen.� The initial wave of �pioneers�would consist of merit based selected colonists who would essentially test�ther�s CELSS reliability, then a �first come, first serve� selection processwould be initiated for the �settlers,� who would take the remaining open slotsin �ther.� Companies could also applyfor a group permit, but the available slots for companies would be limited sothat the opportunity to live in space would be presented to individuals.� Equal representations of both sexes would bedesirable, as well as representatives from most major cultures.� The screening process for the pioneers willnot be as selective as those conducted for astronauts, but those who go willfirst most likely be above average in cognitive and spatial aptitude, bewilling to take risks, be cooperative, and be emotionally mature andstable.� The pioneer population will bearound 5,000-10,000 and will live in �ther for 1 year before the settlerapplication process begins.

IV.B.2 Health Care

����������� Maintainingdistinguished health care facilities will be important for attracting permanentresidents to �ther.� The ideal healthcare system would provide the best health care available while respecting therights of the physician and the patient [ref 32].� A sufficient number of physicians is needed for the proper healthcare of the colonists, and some specialty services would also be provided, butfor some extreme cases that would not be able to survive the journey back toearth, transportation of specialized doctors from earth would have to bearranged.� Hospitals and emergencyvehicles would be provided for, and the goal of one doctor per 400 personsshould be maintained to provide quality care.

IV.B.3 Communication

����������� Communicationcan be divided into communication within �ther, communication between �ther andother space habitats or earth.Communication serves both task and socio-emotional functions [ref 14].� Task communication involves the organizationand coordination of work, while socio-emotional communication is more of apersonal nature.� Communication within�ther will mostly be in the form of verbal and nonverbal communication.� Ambient noise from machinery and its implicationson communication has already been discussed prior; however, decreasedatmospheric pressure will also impair sound transmission, and colonists wouldbe required to talk louder than normal.For obvious reasons, all colonists must be fluent in a common tongue,this requirement is especially important in demanding situations, when ahuman�s ability to process complex information is diminished.� Using current standards, the officiallanguage onboard �ther would be English.However, even when two or more people are communicating in the samelanguage, there exists the problem of regional dialects and accents.� Obstacles to effective communication wouldinclude subtleties of intonation, inflection, context, meaning, andinterpretation [ref 14].� However, theseare mostly unavoidable obstacles, as the colonists will come from many culturesand regions.� Hopefully, the situationwill rectify itself as the colonists interact with each other and develop a newdialect of English.� Nonverbalcommunication has three modes: paralinguistic (amplitude, rate, and tenor ofspeech), kinesic (facial expressions and gestures), and proxemic (distancing orplacement).

Nonverbalmiscommunication will occur in the micro-gravity regions of �ther, whereproxemic and kinesic modes of nonverbal communication will be hindered by thepuffiness of the face and difficulties in anchoring oneself.� Again, cultural and regional difficultieswill cause proxemic miscommunication, since different cultures considerdifferent distances as too close or too distant [ref 14].

Communicationbetween �ther and other space habitats or earth will necessitate the use of anelectronic medium; thus, satisfactory bandwidth will need to be achievedbetween these three points.� Thiscommunication will be in the form of different types of media such as fullmotion video, audio, written messages, and data.� This type of communication will be of utmost importance tocolonists who have left family or friends on earth to live in space.� Generally, if the dialogue is between familymembers, full motion video is the preferred means of communication as itcontains the most modes of communication (kinesic, paralinguistic, andlinguistic).� However, communicationthrough normally instantaneous means is made awkward because of the timenecessitated for the electromagnetic wave to traverse the distance in betweenearth and �ther.� The time lag that isintroduced would be noticeable, but not overwhelming.� Given the fact that real-time full motion video isbandwidth-consuming, adequate bandwidth must be allocated to facilitate themassive demand that would be placed on this service inside �ther and between�ther and earth.�

Audiocommunication is next in being most information-rich as it contains bothparalinguistic and linguistic modes [ref 14].Many technical challenges are present with a fully duplex audiocommunication system in which both users can speak at will [ref 14].� Attaining high quality in audio is alsodifficult if not using free arrangements (where individuals are attached tomicrophones and earphones), but is essential for frequent usage andsatisfaction of the system.� Audiocommunication has the advantage that most users are familiar with telephonicdevices on earth and that it offers more privacy over video communication.� If high audio quality is attained, then thismeans of communications will account for most communication inside of�ther.� Written messages are only ableto transmit text and pictures and are limited to the linguistic mode ofcommunication.� Most written messages in�ther will assume the form of computerized exchanges, thus an infrastructurefor handling this medium will need to exist.

In gainingwidespread acceptance of the video, audio, and written lines of communicationonboard �ther, the designer must fully understand the colonists� needs, thebenefits of the designed system must be made clear to the colonists, and thecolonists need to be properly trained in the operation of the differentsystems.� Integrating the opinions ofpioneers into the design process is helpful for designers trying to understandthe attitudes and needs of people living in space [ref 14].�

IV.B.4 Privacy

����������� Privacyis arguable one of the most difficult and perplexing parts ofhabitability.� Not only do individualshave varying levels of privacy, the notion of acceptable privacy differs fromculture to culture.� Given the contextof an international population living onboard �ther, designing for privacy is acomplex issue.� The term �privacy�refers to a plethora of meanings, such as the �need for adequate space; visual,physical, or psychological separation; low population density; control overspace, possessions, or information; freedom of activity; and many otherconcepts� [ref 14].� One definite way toease the sense of little privacy is to ensure that each colonist receives anample amount of space that he or she can call his or her own.� Another is to allow the colonists to controlinformation about themselves, thus there should not exist detailed dossier of answeredquestionnaires and on each and every colonist.A sense of privacy is further enhanced if homes and apartments aresufficiently acoustically insulated so that conversations can be kept privateand annoying ambient noise kept to a minimum.Crowding will become less of a problem if neighbors become acquaintedand become friends instead of merely being strangers who live in a closeproximity.

IV.B.5 Entertainment

Off-dutyfunctions are essential to balancing the colonists� work.� Most recreational activities available tohumans on earth must also be available to colonists.� Humans have a tendency to choose passive entertainment overactive entertainment [ref 14].� Passive entertainmentis usually in the form of mass media such as magazines, television shows,movies, etc. and can easily be provided for in �ther.� However, active entertainment is also an important means ofrelaxation and the needs of the colonists in this aspect should be addressed.

Some types ofentertainment would not be available to colonists because of severalreasons.� Smoking will be strictlyforbidden as it would place too great of a strain on the CELSS air managementsubsystem.� Other recreational drugs inthe form of sedatives, stimulants, hallucinogens, and painkillers have shown tohave no positive uses outside of the medicinal world and will not be availablefor recreational purposes due to the negative effects brought about bylong-term use.� One exception would becaffeine, and others could probably be found given more research.

Not only mustconventional active and passive entertainment be provided, but other, novelentertainment should also be available to enhance the appeal of living in�ther.� Given the exotic locale of�ther, such entertainment will be plentiful.Such entertainment could be earth-based activities that have beentransplanted into a zero-g environment such as swimming, handball, and tag, ornew activities that the colonists invent.

IV.B.6 Education

����������� Providinginspirational education is key to combating boredom and creating a sense ofpersonal growth.� The learning processis continual and should be aided and encouraged by both school andcommunity.� Due to the size of �ther,schools of decent size would be able to be constructed for pre-primary throughpost-tertiary education.� In theprimary, secondary, and tertiary schools there should exist a plethora ofclasses, but not at the expense of quality.Core classes in the basic sciences, mathematics, languages, socialsciences, and fine arts should be complemented and applied to daily life inother classes.� Being able to chooseclasses would alleviate the deprivation of control in an artificial environmentsuch as �ther.� The structure of theeducation system in �ther should be left for the colonists to decide, but itshould be noted that constant interaction between different ages is beneficialto the unity and development of the community.Educational opportunities for older generations should be made availablein either distance learning or �night classes� offered at tertiary educationalestablishments.

����������� Schoolsare not the only places where education occurs, cultural establishments such asthe library, museums, and research centers also offer excellent educationalopportunities.� The library could serveas a book repository for school classes while also serving the general public.

IV.B.7 Interior Transportation

����������� Lifeonboard �ther will require efficient means of transporting colonists from anygiven place inside �ther to another place.Public transportation would be the most effective way of meeting thisneed, since it can transport people using a minimum of infrastructure andenergy.� Design goals for publictransportation should include low jerk rates (1-2 m/s³), lowaccelerations and decelerations (1.5 m/s²), insignificant or nofares, fast transit speeds, pleasant accommodations, high reliability, littleto no noise, and extreme safety [ref 42].Transit speeds should be fast so as to not cause inconvenience, but shouldnot be so fast as to cause massive Coriolis forces.� Thus speeds tangentially in opposition to or in conjunction withthe rotation of the colony should cause no more than a 0.1g deviation, thus theapproximate maximum speed should be 7 m/s (26 km/h).� Monorails will be used to provide �therians with fast publictransportation.� Monorails trains areeither suspended or supported by a single rail.� Wheels that make contact with the rail supply the forward motion.� Because of their simplicity, monorailsoperate quietly, efficiently, and reliably.The monorail line would be constructed so that passengers will have agood view of the colony interior, but will not be so high as to cause largeCoriolis forces when the passengers embark and disembark from themonorail.� Bike and walking paths wouldalso be built to facilitate easy access.Transportation from the torus to the spheres would be handled byelevators inside the connecting spokes, which would also move slowly to preventuncomfortable Coriolis forces.