Biosphere Construction

Hey: just tossing some ideas about regarding the construction of an enclosed biosphere.

First off, I would want it buried, or partially buried (for an earthbound closed system). I would have to built across a series of piers dug into bedrock, preferably. Across that would be an array of steel girders to provide a solid, unshifting foundation. Wouldn't be able to have the structure shifting in such a fashion as to cause cracks in the seal - as that would defeat the putpose. Also, there would likely be a sizable gap between the walls and the edge of the hole it's sitting in. This hole would have to be irrigated, of course; but that doesn't pertain so much to the actually construction as it does to the circumstantial location where it's being built.

Next, it would need some sort of rigid exo-structure. Something like a cement wall made of stacked cinder blocks. They would be self-supporting, and would comprise of a floor and the outside walls. These would be padded around with a stiff form of durable, but flexible insulation. A super stiff styro-foam would be good here. Lastly, it would be sealed on both the inside and outside surfaces using some sort of unimpregnable material. Painting it all with a very thick coat of latex could work here.

At this point we have a perfectly sealed... bowl. We would have to erect some sort of central supporting structure that would be the principle load bearing setup. Depending on the layout, this could support only the roof, or possibly a second floor. This all depends on the circumstances required for interior layout, and has less to do with the superstructure.

At this point, we get concerned about the ultimate goal of the exercise: do we concentrate on the closed biosphere, or do we worry about construction techniques that can be extended into the space program. I would argue that the first time we do this, just worry about the closed biosphere research.

So, we place a glass (or some other highly uninhibitive material) roof on the beast. Make an airlock in one corner of the roof, and position some mirrors so as to concentrate solar light through the roof. Also, set up a solar array, (or use a geothermal source) to generate a renewable energy flow. Between the single air-lock, and the outside stable energy source, it should be feasible to sustain life inside for extended periods of time. The target timeframe should be 10 years or better without resupply, and it would be permissible to obtain a significant initial store before beginning the experiment. Perhaps we do it in a series of step-ups, starting at short durations, and working up to the very long durations. Ultimate goal would be relatively perpetual sustainability.

Phase two would see a second biosphere built from the knowledge gained of the first system. However, this time more compact and lightweight construction techniques would be used - keeping in mind that a similar creation could be built for the purpose of space habitation. This means building radiation shielding into the equation, as well as designing in a shape that would be able to be rotated if in zero-g. This actual system may be to scale, but things would still be oriented to earth gravity (IE: down!), and the structure would have to be able to support it's own weight.

During this second phase, a modular construction type would be used, such that the third revision would be able to be lifted into orbit in peices if we ever came to that...

All in all, a long and hefty project. But it isn't evil. *grins*