SUSTAINABILITY

WHAT IS SUSTAINABILITY?
We use the term "sustainability" to mean the use of local resources so that residents on the Moon and Mars don't have to have everything shipped to them at great cost. Without this technical sustainability, all other types of sustainability are not possible. The lower the shipping costs the easier it will be to continue any funded program and close any business case. By using local resources and recycling, future generations can have access to these resources.

WHY SUSTAINABILITY?
There are many benefits from sustainability. Reduced shipping costs is an obvious benefit. It makes it much easier to continue development of a base and settlement even if funding were to be reduced. Also, if for any reason cargo ships from Earth were to stop, a fully self-sustaining settlement would be able to continue. Finally, if a settlement were to grow to the point of seeking political independence from Earth, achieving material independence would enhance that possibility. But one doesn't have to go that far. Just reducing shipping costs is benefit enough.

MEASURING SUSTAINABILITY
Sustainability isn't a nebulous concept. We can measure it. It is the reduction in mass that has to be transported from Low Earth Orbit the more a base becomes self-sustaining. So, if we can achieve a 50% reduction in cargo mass then we are 50% self-sufficient. If the base is so self-sufficient that our needs are reduced by 90% then we are 90% Earth independent by mass.

High levels of sustainability can be achieved more easily than commonly presumed. The key factor is that most of the bulky mass is "dumb mass" meaning that it is one kind of material without a lot of hard-to-produce complexity. Dumb mass includes, propellant, water, air, CO2 for plants, gross metals, and even plastic. And, although food is very complex at the cellular level, we don't have to manufacture each cell -- it manufactures itself. By contrast, high-information material such as motors, sensors, and electronics tend to be fairly low mass. For this reason, we believe that a greater than 75% sustainability level can be achieved within the first five to ten years of the establishment of a permanent base.

Recycling means getting to use the same resource repeatedly. As they like to say on the International Space Station (ISS), "Yesterday's coffee is today's coffee" if you know what we mean! Recycling can go a long ways towards increasing the self-sustainability of the base. For example, water shipped to the ISS can be recycled at 93%. So one could ship one liter of water and it will last as long as if one were to ship 14.3 liters of water without recycling.

SUFFICIENT SUPPLY
High-information components (e.g. electronics including chips) can be produced on Earth and shipped to an off-Earth base at lower cost than trying to produce those things at the base. For achieving economic sustainability, this makes the most sense. But for those goals requiring full self-sufficiency one can stockpile large quantities of these items and hence buy the base a very long time before it would need to be further resupplied. During this amount of time, the base could implement technology protocols to produce good-enough replacements (e.g. 8086 chips). Using this approach, full self-sustainability can be achieved just as soon as the stockpiles are large enough such that the base could survive indefinitely without needing any fruther shipments. Using ISRU and sufficient supply we believe that full self-sustainability could be achieved many years before a million-person city on Mars could be established.

IN SITU RESOURCE UTILIZATION (ISRU)
ISRU is the term used to described the harvesting of local resources and using it at the base. Volatiles include things such as water, carbon, nitrogen, and sulfur. These are present in sufficient quantities and concentrations on both the Moon and Mars. Metals come in different forms and their locations are also known for both the Moon and Mars.

GROWING FOOD
Food makes up a substantial part of shipped mass because it is constantly being consumed. So growing food will be an important, early goal.

The Agriculture Working Group (AgWG) of the Space Development Network has sought to identify the best approach to growing food. Our design is to start with large inflatable habitats, telerobotically cover it with dirt for radiation shielding, and use solar panels to produce electricity to power very specific LEDs. Rocks would be crushed and mixed with organics to make soil while using a pumping system for a hybrid soil-hydroponics approach. The GreenHab environment would be optimized to maximize production. Tools and machines would be used to reduce labor requirements. The goal would be to meet all of the nutritional needs of the crew while recycling plant waste.

MAKING HARDWARE
Metals would be extracted from local sources and processed to produce basic metal materials such as blocks, sheets, bars, tubes, wire, and metal powder for 3D printers. Then machining equipment would produce components which would be assembled into equipment including more machining equipment.

MAKING HABITATS
Another big challenge for achieving full self-sustainability is that of producing habitats from local materials. The Network keeps a near-term focus and our goal is to attempt to demonstrate full self-sustainability in an analogue base in Texas. For these reasons we will be using the Martian context as described below. So our plan is to start with a large inflatable working hab. Plastics would be produced from Mars air and water ice simulants and molten plastics would be pumped into molds. In this manner, sections of a double-walled PlasticHab would be produced and then fused together by microwaving metal particles between each section. By so doing, PlasticHabs could be created which could be connected to each other for an ever-expanding base.

THE MARS CONTEXT
The Moon has all of the elements need to acheive full self-sufficiency. In particular, the lunar polar volatiles have been proven to have those elements (including carbon and nitrogen) in the quantity and concentration needed to sustain a base growing into a very large settlement.

That said, Martian resources are significantly easier to extract. Whereas volatiles can be obtained telerobotically from permanently-shadowed craters at the lunar poles, we can get those on Mars simply by sucking in and concentrating the Martian air.

Unoxidized metals are also much easier to obtain on Mars than the Moon. Three rovers on Mars have already seen about 50-60 nickel-iron meteorites. These make ready sources for machining parts that have to be metal (and not plastic).

For these reasons it will be much easier to demonstrate full self-sustainability (FSS) using the Mars context our Moon-Mars Analogue Base. Indeed, our current opinion is that we can demonstrate FSS without needing to produce integrated circuits. Any FSS demonstration using the Moon context will wait until we do so using the Mars context and after greater funding is secured.

THE SUSTAINABILITY PROJECT
We hope to secure funding for a new type of analogue base - the Moon-Mars Analogue Base (MMAB). Projects conducted there will follow a Plan for illustrating and demonstrating for how an initial permanent base could operate. But a large and important side project will be the Sustainability Project in which we seek to demonstrate full self-sustainability given Mars analogue inputs. This will require a great deal more research, planning, and funding than we have had so far.

GETTING INVOLVED
If the Sustainability Project interests you and you think that you have what it takes to help this project in credible manner, feel free to contact us at: DevelopSpace1@gmail.com.