CELSS (Closed Ecological Life Support System) is a "living machine" which, ideally, provides it's inhabitant(s) with 100% of their life support (organic food, fresh oxygen-rich air, clean water) by recycling the waste products generated by the inhabitant(s) and by the CELSS itself. We call that "closing the loop". As it has been said, "the devil is in the details". CELSS is relatively new in the world. Now, of course, the planet-wide life supporting biosphere it a large scale CELSS. By studying what nature does to recycle we may apply these principles on a much smaller personalized scale. It helps to design for the worst possible scenario in the harshest environments (like Mars) and then it becomes easier and simpler to build robust systems for kinder climates. So, to start, imagine we have landed on a barren planet with no air, water, or food to eat except what we brought with us. Here's what we have to work with (this can get gross):
1) HUMAN BODY: feces, urine, farts, belches, vomit, snot, spit/saliva, phlegm, sweat, tears, earwax, milk, sperm/semen, smegma, menstrual blood, blood, pus, nail clippings, hair, dead skin, water vapor, CO2, trace gasses, heat, medicine residues, and (if someone dies) dead bodies and body parts
2) PLANTS: unused biomass, garbage, plant oils, O2, CO2, ethylene and other trace gasses, water vapor
3) ANIMALS: much the same as what humans output
4) MATERIALS & PROCESSES: oils, soaps, worn out clothing (composed of natural fibers/dyes only), laundry & wash (gray) water, out-gassings (solvents/trace gasses from materials used in the CELSS shell construction and other items inside the CELSS).
That's what we have to work with in the "hermetically sealed version". Of course, on Earth or anywhere there are some useful outside resources, our task would be easier. Yet, if we design the hermetically sealed version, I`m sure, on the way to the final design, we will cover just about any condition or environment we can imagine. While we are brainstorming this "ultimate CELSS" we need to be aware of the amount of energy required to make the whole thing work. The less energy required the better. Also, technologically complex systems tend to break down faster than simple systems. We adhere to the engineering principle of KISS (Keep It Simple Stupid). We don't want to design anything which requires a lot of repairs, maintenance, or spare parts. The number of human hours spent per day keeping the system fully operational should also be considered. We're not into this to work ourselves to death. We shouldn't have to spend more than a hour or so a day doing our chores in an optimal system. Remember, we're on a planet's surface so we have gravity on our side. In space we would have to spin the whole thing to simulate gravity. For now, let's stay grounded and focused on the transformations.
The MATERIAL INPUTS listed above must be transformed into the following:
1) nutrient rich water and soil for plants, fungi, and symbiotic micro-organisms
2) CO2 and trace gas-rich air for the plants, fungi, and symbiotic micro-organisms
3) clean water for humans and animals
4) oxygen rich air with few trace gasses (ethylene, methane, carbon monoxide, and other exotics) for humans and animals
5) continuously and regularly producing organic food supply for humans and animals
Get the picture? What goes around comes around. There is a dynamic relationship between humans, animals, plants, fungi, and symbiotic micro-organisms. What we are trying to do is optimize this relationship by building containment vessels which provide optimal conditions for each of the above. We want to make everyone and everything involved very comfortable and in a state of being nurtured at all times. We also want to do this in a way which prevents pathogens from thriving. We're aiming for a high oxygen level (aerobic) conditions throughout the CELSS. Anaerobic conditions (such as found in septic systems) are to be avoided because they breed disease and poisonous gasses like hydrogen sulfide (rotten egg odor) and methane. Plants out-gas ethylene which is, at certain concentrations, a growth inhibitor for the plants. It too needs to be converted or a hermetically sealed system will die.
How large should a fully operational CELSS be? As small as possible and small is possible. Here are some optimistic figures from the CELSS life support research community:
ESTIMATED GROW SPACE REQUIRED PER PERSON
(may be stacked into multiple levels for more efficient operation)
14 m2 - Gitalson
56 m2 - Bios3
20-30 m2 - Cullingford & Schwatekopf
13-50 m2 - Bugsbee & Salisbury
56.9 m2 - Oleson & Olson
8-20 m2 - MacElroy & Averner
15-20 m2 - Eckhart
24 m2 - Hoff
15 m2 - Vasilyew
As you can see, the above figures are tiny compared to the amount of space the average human being requires for life support in both hunter/gatherer and agriculture- based civilizations. Since the Earth's "carrying capacity" is already exceeded because of the rapidly expanding human population, anything we do to reduce an individual's "footprint" (space/resource required to keep a person alive) is a step in the correct direction. Lab work (NASA Ames) has already proven that all the air, water, and food for one person can be grown in a 16' x 16' space under optimal conditions with controlled atmosphere, temperature, lighting, and nutrients. Of course this was a highly engineered "hydroponics" style system which required considerable electricity for the lighting, pumps, and climate control plus an outside source of plant nutrients. So, it cannot really be called a CELSS but it sure is an encouraging experiment. I bet we can do pretty good together too!
That's enough for the moment. Read through the above a few times and start dreaming of how you might turn each of the MATERIAL INPUTS into what we need to get in return. If you have any ideals fleshed ot in some detail, please share them with the group. My job here is to facilitate the "think tanking" and keep us on course to building a functioning CELSS. I'm going to be poking and prodding so don't take it personally when I question you input or put a new twist into the puzzle. Doing so is part of my job facilitating this group. One thing I'm going to be stressing is INTEGRATING FUNCTIONS. If one piece of hardware can do 3 things simultaneously, I'm probably going to suggest it.
Looking forward to working with you all! - Terry Ryan Kok (aka: Jade)