It has been made clear that for long-duration spaceflight or long-duration stays upon another planet or Moon, we must develop a means to support ourselves while there. The best duration of human life beyond our planet is currently in the range of two weeks. By providing recurring supply deliveries at a frequency of one every six weeks, we have been able to extend the stays of astronauts aboard the ISS for 20 years.
As we move from Earth orbit to the Moon, such supply shipments will very quickly become economically, and logistically strained. We must develop life support systems capable of supporting not just one or two persons, but teams or even communities. Residents that will stay for not just weeks, but years at a time.
The challenge revolves around not only providing air, water, food, and waste processing for scientists on the Moon, Mars, or Beyond; but being able to continuously supply that life support without receiving materials and goods from Earth. All current forms of life support systems used today are based upon technological solutions, using chemical, or electronic devices that perform very specific, highly technical tasks. Each of these devices requires some form of catalyst, additional components, that trigger the reactions to do the conversions that ultimately provide oxygen, and freshwater to those that have to work within the environment. It is important, that waste products (save urine) are not processed, but discarded in departing cargo vessels to burn up in the atmosphere. Not only does this lose an important source of biomass, but the process destroys raw materials in devices, parts, and soiled uniforms of the crew.
It is clear that a traditionally technological solution, because it is based on the industrial supply chain, is not going to serve us in the long term. Instead we must reorient our thinking to a new and different perspective. In our current civilization, we humans are the ultimate consumer of resources. We must become the shepherd instead.
In agriculture, when a plant matures, it releases a seed. The shell contains everything that the small seedling will need to travel, establish, and grow at its destination to reach a stage where it can draw additional nutrients from it’s surroundings. As such, if we are to achieve a biological life support system we must mimic this mechanism.
First, everything needed for human life support must exist within the environment that the humans are transporting in, and will set up, at their destination on the moon. Given that all of the components nutrients and supplies must be present, it would seem that we would need to transport large quantities of supplies when we go. But this is a misconception.
In fact following the principle of the biological seed we only need to provide minimal sufficient supplies to help us reach an equilibrium point, where we can acquire our supplies through, or from our new environment. This does not necessarily mean that we can only visit locations that have carbon, nitrogen, oxygen, hydrogen, etc. in easily accessible components within the environment. What it does mean is that as nature on our planet recycles everything, and I mean everything, we must consider ways to do the same once we arrive at our destinations. But even then, recycling is only one part of the equation. We must engage other species to participate, in much the way they do here on Earth.
I have formulated a simplistic View that starts with four principles or components. These components are first air, then water, then food, then wastes. I described them in this order because it is the order in which they are most important to our bodies.
AIR
Air, or rather the oxygen necessary for us to breathe is the first and most critical element we must be able to provide within our biological life support system. Without the oxygen in our air, we can suffocate within just moments. Nature fulfills this using multiple layered biological systems. The largest and greatest of these systems, and perhaps the most prolific system, is one of the smallest organisms living on our planet today: cyanobacteria. A recent paper discussed recent progress in understanding the oxygen output and carbon dioxide sequestration of several species in lab experiments. Early estimates of the required amount of cyanobacteria culture medium we’re estimated in gallons or hundreds of gallons of culture material to provide the minimum oxygen requirement for one human. It was suggested in this new paper, that in fact it may be possible to reduce the culture medium quantity to as small as 21 liters.
WATER
Our second parameter is water. Without it, we perish in as little as three days. Life giving water is a chameleon, that can be found in many forms. It provides the home for the cyanobacteria discussed in the first section. Water is perhaps the most renewable resource on the planet. It can be recycled over and over; it can carry wastes away, bring fresh supplies of fish and other foods, and as well, it provides a foundation for cooling – or heating, in our homes.
FOOD
Our third parameter is food. A human can generally survive up to seven or eight days without food, before death overtakes you. Ergo, we’ve got to eat. There are two general methods that we humans use to acquire food: one is to farm it, through vegetable and grain crops; fish farms, chicken farms, sheep, cattle, and other animals that we husband. As it has for thousands of years, we assume it will continue to be the most straightforward, economical, and consistently productive method to produce food. As such our biological life support system will include a garden of sufficient size to produce leaf crops, root crops, and fruiting crops in order to provide basic sustenance within the Habitat. But it must also be understood that the farm not only provides human food, but the garden provides a home for other biological components that interface and interact with the plants, their roots and the water flowing beneath them to facilitate the growth of those plants.
In addition, we must also produce compact high protein animal food sources, for fish, and chicken or ducks, such that when integrated with the garden, the whole can provide balanced, nutritious meals for the residents of the habitat. We shall come back to this integration Factor after we discuss wastes.
WASTES
We recognize that rather than referring to the byproducts of digestion and metabolization as wastes, we should understand that one creature’s wastes are another creature’s food. In the same way that cyanobacteria consume carbon from carbon dioxide, and the plants consume the fish wastes, so too the Black Soldier Fly larvae are ravenous feeders on fecal matter – human and animal. This property lends their species the benefit of being able to live in the toilet facility. By incorporating BSF, we do not have to bag, and destroy the waste material of humans, and can retain the biomass within the habitat.
CONCLUSIONS
The discussion above includes only a small fraction of the components that we have realized, and are including within our habitat design. And that list continues to grow. So far we have learned how to include 10 different species that with the shepparding of humans, can provide Air Recycling, Water Recycling, and food/waste recycling. These processes have the capacity to close the multiple cycles in a Biological Life Support System, providing for all the sustenance needs of the humans within the habitat.
Be cautioned, while these results are promising, there is a caveat. Our progress has been made by starting with a small system. As Biosphere 2 found, there are variables upon variables to be addressed. Working from our small footprint, we have hope to not repeat the mistakes of others as we move on to Phase 2: Integration Prototype.