Monday, August 3, 2015

The Basics

Some say space is hard. Things break, people die.

It's still true.

We are in our infancy, struggling to find our feet and set out on the path to a sustainable and permanent presence in space. We have learned an enormous amount from the first pioneers. We have a framework, we do tests, we simulate. Still, things go wrong. It's unavoidable.

Set aside for a moment our current state. Look to the future. How would a permanent human colony look?

 First off, radiation in space is a huge problem. Without shielding your lifespan drops to a few years at best or one bad solar storm at worst. A permanent colony will be shielded against radiation (and by extension against micrometeoroids).
 Second, a colony requires a broad range of resources. Water, oxygen, plant nutrients like carbon, potassium and phosphorus, structural materials like aluminum, titanium and iron, and inert gases like nitrogen and argon. There is no one place in the solar system to find these things other than Earth, so the colony will be built close to the elements which are rarest and most difficult to harvest or transport.
 Third, the colony needs to produce its own food and maintain its own atmosphere. More than that, it needs to be able to build the parts and tools necessary to do that for an expanding population. That means complex manufacturing processes turning out semiconductors, zeolites, pumps, filters, pressure vessels, heating coils, etc.
 Fourth, an enormous amount of energy is required. In space nothing is free. Using LED lighting, it can take up to 15 kilowatts of power just to feed one person. While efficient, that process still produces nearly 15 kilowatts of heat that has to be removed. Getting rid of heat is complex and awkward in space because there is no convection or conduction (generally speaking), so only radiation comes into play; that requires a lot of radiator area which can compete with solar panels for available space.
 Fifth, a colony needs to be accessible. If the chosen location is too remote then the initial construction will be prohibitively expensive. In addition, most practical paths to self-sufficiency start with trade between the colony and Earth. If shipping times are long then the value of goods is reduced. This also makes it easier to maintain lifeboats if that option is used.

So, this future colony is heavily shielded (literally heavy). It has heavy manufacturing processes; most visible are those that use solar reflectors for heat (carbonyl processing of iron/nickel, zone refining silicon and rare earths, melting basalt for fibers, sintering regolith blocks). It has large areas of solar panels and almost equally large areas of heat radiators. It is physically large with abundant space for the people living there and the systems (both biological and mechanical) that keep them alive, but the habitable area is not visible from the outside (no giant glass windows).

 In future posts I will describe a plan for a colony that meets these requirements. There are several places it could be built; a larger program of colonization would use two or three of the prime locations and share the benefits between them.
 I intend to get as in-depth as I can given the information available. I don't have access to simulation tools and I'm not a structural engineer, so a lot of this information will be a first guess based on assumptions, rules of thumb, research paper abstracts and other unreliable sources. Still, there are some surprising resources available to the general public and I will try whenever possible to point them out.
 There are several others out there pushing their own orbital colony ideas. That's fine. Competition is good, but so is being able to incorporate the best ideas. I have no reason to believe my designs will ever be built, but perhaps I will see a problem or a solution in a way that helps someone whose design will be built. I'm also doing this for myself to keep my mind occupied, improve my math skills and to give myself an excuse to read research reports and space articles for hours at a time. You're welcome to read along.

If you have not already done so, go over to Project Rho and get familiar with the gritty details of life in space. I find the page on thermodynamics particularly amusing and depressing at the same time. It's a resource for science fiction writers but the information provided is accurate. Follow up with Hop's blog to learn about orbital mechanics, among other things. I will provide links to many and varied references as I use them.

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