Life support
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A life support system is a collaborative series of systems designed to provide a person with the various necessities of life. Normally, a citizen of the Third Imperium will obtain all of these basic necessities simply by living in a city: a person may rent an apartment or buy a home to provide most of their living requirements, and may regularly visit groceries and restaurants to provide their food and drink. In space, this convenience disappears, and persons must track their primary needs a little more closely.
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Light
Light is provided by the basic environment system inside a dwelling, or aboard a vehicle or starship, available at Tech Level 5 and above. If this technology is not available, a person must provide their own illumination.
Candles are popular on planets because they are cheap and do not burn intensely: a candle that is dropped will generally go out, whereas a torch that is dropped will generally start a fire.
In space, the rate of oxygen consumption of a candle is usually considered too prodigious for low-technology life support systems; the lack of artificial gravity would also prevent the candle from being ignited without flash-burning the entire compartment. A single candle consumes a significant amount of oxygen in an hour, many more times than does a human being.
The light required for comfortable reading is measured at 50 lux, although human eyes can read at illuminance levels as low as 10 lux with significant effort. 100 lux is required for easy perception of detail, with eye strain for detail possible at 20 lux, and is the illumination of a typical corridor. A brightly-lit room in a typical office is bathed in 400 lux. A sunlit day on Earth when the sun is directly perpendicular (as on the Tropic of Cancer during summer) is approximately 100,000 lux, for comparison.
Food
Food provides the fuel for human life, and people must maintain certain dietary standards in order to maintain peak effectiveness.
TL Food Cost Volume Mass Classification ---- ------------------------------------ -------- ------ ------ ------------------- 0 Fresh Vegetables, Gathered, 8 kg 60 15 8 Natural Resource 0 Fresh Fruit, Gathered, 8 kg 55 13 8 Natural Resource 0 Fresh Berries, Gathered, 8 kg 50 11 8 Natural Resource 0 Fresh Seeds, Gathered, 8 kg 80 8 8 Natural Resource 0 Fresh Nuts, Gathered, 8 kg 75 9 8 Natural Resource 0 Fresh Meat, Hunted, 8 kg 90 8 8 Natural Resource 0 Fresh Fish, Speared, 8 kg 60 8 8 Natural Resource 1 Fresh Vegetables, Cultivated, 1 t 250 1 875 1 000 Processed Resource 1 Fresh Fruit, Cultivated, 1 t 275 1 625 1 000 Processed Resource 1 Fresh Berries, Cultivated, 1 t 300 1 375 1 000 Processed Resource 1 Fresh Grains, Cultivated, 1 t 250 1 000 1 000 Processed Resource 1 Fresh Seeds, Cultivated, 1 t 375 1 000 1 000 Processed Resource 1 Fresh Nuts, Cultivated, 1 t 550 1 125 1 000 Processed Resource 1 Fresh Meat, Ranched, 1 t 1 750 1 000 1 000 Processed Resource 1 Fresh Fish, Netted, 1 t 850 1 000 1 000 Natural Resource 2 Fresh Vegetables, Cultivated, 1 t 150 1 875 1 000 Processed Resource 2 Fresh Fruit, Cultivated, 1 t 200 1 625 1 000 Processed Resource 2 Fresh Grains, Cultivated, 1 t 200 1 000 1 000 Processed Resource 2 Fresh Seeds, Cultivated, 1 t 300 1 000 1 000 Processed Resource 2 Fresh Nuts, Cultivated, 1 t 450 1 125 1 000 Processed Resource 2 Fresh Meat, Ranched, 1 t 1 500 1 000 1 000 Processed Resource 2 Fresh Fish, Netted, 1 t 650 1 000 1 000 Natural Resource 7 Fresh Fish, Cultured, 1 t 500 1 000 1 000 Processed Resource
- Cost is in Credits (Cr).
- Volume is in litres (L). There are 1000 litres per kilolitre (kL). There are 13.5 kilolitres per displacement ton (DT).
- Mass is in kilograms (kg). There are 1000 kilograms per tonne (t).
- Classification is the Trade Classification of the commodity, for purposes of imports and trade. See p.52, Referee's Manual.
Every day, a person consumes approximately 1.5 kilograms of food. For most common eating habits, lunch is the largest meal of the day at approximately 750 grams, followed by dinner at 500 grams and breakfast at 250 grams. Other routines divide the daily intake into three square meals of approximately 500 grams each, or into two square meals of approximately 750 grams each.
Fresh Foods
Fresh foods are foods that have been extracted directly from the environment or from semi-intelligent lifeforms. Fresh foods include meat, fruit, vegetables, grasses (and/or their grains), seeds, and berries.
Fresh foods are very healthy, flavourful, and nutritious and are what most people prefer to eat. However, they are also extremely bulky and spoil quickly, even if stored in a vacuum-filled cargo bay (which tends to cause the food to lose its palatable consistency).
At very low tech levels, fresh foods are extracted by hand, hand-picked by gatherers or slain by hunters in the open wilderness. Such foods are so difficult to come by that they are extremely expensive to buy from others; most family groups work to obtain their own food and do not share or trade with other family groups unless considerable value is offered.
As agriculture and domestication are better adopted, fresh foods become considerably easier to obtain, though the additional work required to grow the plants and then harvest them causes them to be classifiable as Processed Resources instead of Natural Resources. Fish are still obtained in the wild by netting, and continue to be netted until the adoption of aquacultured fish in the TL7 era introduces an alternative—though sometimes problematic—solution.
Spear-fished foods, wild-picked foods, and hunted foods continue to cost as much as they did in the TL0 era; though technology and knowledge improves over time, the sheer lack of skillful hunters and the depletion of resources that comes with better technology ensures that costs remain relatively stable over the ages.
TODO shelf lives
Dried Foods
Dried foods are fresh foods that have had their water content removed; they are designed to be transported overland in an environment that has plenty of natural water. If water can be obtained freely from the environment, dried foods weigh half as much as fresh foods and take up less volume for the same nutritional value. They are also much less perishable, lasting nearly ten times as long as fresh foods.
When carried aboard a starship, or overland in a climate that has no water, dried foods must still be accompanied by water, usually stored in barrels or tanks. In this case, the dried foods provide no advantage in volume or mass over fresh foods, but still provide a considerable advantage in terms of perishability.
TODO shelf lives
Prepared Foods
Prepared foods are foods that were once fresh foods but have been processed to produce new foods. Examples of prepared foods in a TL8 society, for instance, include burritos, waffles, candies, etc. All prepared foods are ordinarily stored in boxes or crates and are given preservatives. Once a container of prepared food is opened, it is then usually treated as fresh food and will spoil if not kept frozen or kept cool.
Prepared foods are less healthy for a person than fresh foods, due to the high quantities of preservatives and micro-nutrients that arise from the preservation processes. Most food consumed in any TL8 society ranges from ten percent to thirty percent prepared food.
TODO shelf lives
Preserved Foods
Preserved foods are foods that have been specially prepared for long shelf life, usually by being stored inside cans and other impervious containers.
TODO complete description, shelf lives
Artificial Foods
Artificial foods are foods that are designed to provide all of the body's nutrition in a perfectly digestible format, with no wasted nutrients or fibre. Such artificial foods include liquid meal replacement beverages, nutrient pills, and synthetic food paste.
Artificial foods are intended for short term consumption only; aside from being relatively tasteless or filled with micro-nutrients that lend a metallic flavour, a lack of continued bowel movements over a long term (one week or more) from the artificial foods will cause weakening of the gastrointestinal tract and an overall sense of discomfort. People who resume a normal diet will suffer from diarrhoea, constipation, and/or unpredictible bowel movements until the atrophied intestinal muscles manage to achieve ordinary equilibrium.
TODO medical issues and tasks associated with long term artificial foods
Cooking
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Water
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Air
Humanoid Consumptions
Humans, Vargr, and Aslan are air-breathing lifeforms which subsist in oxygen/nitrogen environments. Intelligent beings such as these require fairly exacting standards of air to be capable of breathing. Air on Terra is comprised of 21% oxygen, 78% nitrogen, and 1% other gases, including argon, xenon, and other inert gases, as well as tiny portions of carbon dioxide (less than 0.04%).
Aboard spacecraft, a "pure" atmosphere is maintained, consisting entirely of 21% oxygen and 79% nitrogen. Carbon dioxide exists in a limited capacity in rooms where humans are respirating, but is eliminated in its entirety in the atmospheric maintenance systems (assuming they are functioning normally).
Every minute, the average human male inhales 6 L—1,638 milligrams—of air. 21% oxygen and 79% nitrogen (and/or other inert gases) is inhaled. Of this air, some of the oxygen is consumed via the respiratory process, while carbon dioxide (a waste product produced by humanoid tissues) is released. When we exhale, 16% of this air consists of oxygen that was not immediately consumed, and 5% of the air consists of carbon dioxide, with the nitrogen (and other inert gas) being entirely unaffected by the respiration. In other words, out of 1,638 milligrams taken in per minute, 1,294 milligrams of nitrogen are exhaled back out. 344 milligrams of oxygen are taken in, with 262 milligrams of oxygen and 82 milligrams of carbon dioxide exhaled back out. In other words, on a minute-by-minute basis, a person consumes 82 milligrams of oxygen and produces 82 milligrams of carbon dioxide, in spite of having to inhale and exhale over 1,638 milligrams of air.
Despite this wasteful respiratory process, the human body requires that the oxygen concentration remain very specific. In oxygen concentrations lower than 19.5%, humanoids do not get enough oxygen to breathe normally, and begin experiencing trouble. This will lead to unconsciousness within several minutes, and eventual death -- though, if the patient is returned to an oxygenated atmosphere, he or she will recover unless the body's tissues had been damaged severely.
Every hour, a person at rest consumes 4,920 milligrams of oxygen and exhales 4,920 milligrams of carbon dioxide.
A typical 6 metre by 6 metre by 2.5 metre chamber consists of 90 kilolitres of air. If this chamber is filled with 21% oxygen and 79% nitrogen and has no ventilation, then it contains 18,900 L (5,159.7 grams) of oxygen. Because 19.5% oxygen or lower is dangerous, this means that the room only contains 1,350 litres (368.55 grams) of breathable oxygen, which will be exhausted entirely within 75 hours at a standard rate of consumption. However, oxygen is not the only concern; concentrations of carbon dioxide above 0.4% produce disorientation, and concentrations above 0.7% induce rapid unconsciousness. For the carbon dioxide levels to reach 0.4% within the chamber, it would take only 360 L of carbon dioxide. That works out to about 20 hours of breathing. It goes to show you how dangerous life aboard spacecraft can truly be, and illustrates the importance of having oxygen recyclers in most survival lockers.
A kilolitre of volume contains 1,000 litres of air by definition. This air becomes poisoned with carbon dioxide within roughly twelve minutes. This air becomes depleted of breathable oxygen within roughly 48 minutes. Multiply these figures by the number of kilolitres in a location, and divide these figures by the number of occupants in the location to yield a basic estimate on the duration of livable time within that location if all atmospheric processing has failed.
Consumption by Flame
Flame consumes oxygen at an extremely prodigious rate, considerably faster than a human being does. Flame consumes oxygen at a 3:4 rate of oxygen consumed per fuel consumed. A camp fire that consumes 12 kilograms of fuel per hour will consume 9,000 grams of oxygen per hour. As a human consumes 4.92 grams of oxygen per hour, it is clear that the fire consumes oxygen at a far more prodigious rate!
A 600-gram candle burns to nothing within one hour, meaning that the candle has consumed a staggering 450 grams of oxygen, over 90 times the rate at which a human does!
From these figures alone, it is clear that fire in a low-tech life support system is to be avoided at all costs.
Shelter
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Heat
Space is cold, but not as cold as people think. The temperature of any object in space is more or less proportional to its distance from all of the stars in the galaxy, but because the infrared output of any star attenuates cubically with distance, generally only the local unary, binary, or trinary stars matter.
Unlike in an atmosphere, an object in space cools very slowly and warms very slowly. This is because there are three methods of heat dissipation -- conduction, convection, and radiation -- and in space, only the spontaneous emission of heat in the form of infrared radiation is possible. While exposed directly to sunlight, an object warms until it reaches its maximum temperature proportional to its distance from the star(s). While completely occluded from sunlight, an object cools until it reaches absolute zero (in practice, though, the obstruction will also radiate some heat onto the object behind).
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Fire
Fires release, on average, 13.1 kilojoules of energy per gram of oxygen consumed. They consume oxygen at the same rate they consume fuel in a 4:3 ratio of fuel to oxygen. In other words, if 4 kilograms of fuel are burned purely to ash per hour, then the fire consumes 3 kilograms of oxygen per hour and the fire will release 10.9 kilowatts of energy, most of this being released as heat.
TODO
Zero-G Fire
If an open flame is caught in the presence of air currents in a zero-gravity situation, it will simply expand to consume as much oxygen and fuel as possible in as fast a time as possible—fires on planets are kept in check by gravity, but in space, a ventilated fire will flash through an entire compartment and scorch everything inside, assuming there is fuel for it to spread to and its fuel produces gaseous soot (otherwise the flames will simply form elliptical shapes around their fuel sources).
In zero gravity, a fire cannot usually be struck if there is no movement of air: any spark which would set fuel alight will quickly consume and exhaust the supply of adjacent air and replace it with carbon dioxide or some other non-flammable gas. Its oxygen spent, the fire goes out.
Particularly small, efficient flames may be able to persist based on simple diffusion, with newly-produced carbon dioxide spreading outward while available oxygen spreads inward. Evaporated fuel from the source permeates through the burning sphere, allowing a uniform combustion; if the sphere is extinguished, the fuel will precipitate or solidify as a cloud of smoke or a hollow solid-faced ball. Thus, it is possible to light a candle in space, though not particularly advisable. Again, depending on air movement, the small flame may be capable of producing a column of nearly-invisible efficient blue flame of a significant length that may touch off other flammables in the area.
The rate of fuel consumption of such a small flame is significantly reduced in space. Reduce the fuel consumption by 75%.
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Exercise
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Gravity
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