Tuesday 4th of January 2005
Biospheres, et al
Writing about the EcoSphere and the SpaceShipTwo, et cetera the other day threw me off in a tangent. I believe the next pressing challenge in manned space exploration is human life support. How do you sustain Humans on both long space voyages and permanent colonies far away from Earth? -the former could have solutions such as achieving a state of lethargy or just getting to the place in question fast enough that sustenance for long periods of time is no longer a problem. But the latter I believe has only one concrete solution (as I don’t think constantly sending supply ships is a good solution) -recreating Earth’s biosphere.
Only small amounts of matter enter the Earth’s system in the form of meteorites and possibly water ice. Then there’s only a few hydrogen and maybe other molecules (and today, spacecraft) that may reach escape velocity and leave Earth forever. Aside from that, Earth is a system that is closed to matter, but quite open to energy -mostly from the Sun. It gives the necessary fuel for Earth’s many systems and processes in the atmosphere, hydrosphere, biosphere (lovely photosynthesis) and even lithosphere. Eventually, most of this energy degrades to heat, which is emitted back into space as thermal radiation. Some of the Sun’s energy may be tied up for geologic intervals as chemical bond energy in such fossils as coal, oil and natural gas.
Being able to recreate Earth’s biosphere would give us the wonderful benefits of waste recycling, possibly by using green plants (i.e. algae or higher plants) to remove carbon dioxide to produce oxygen and even food for our long journeys, just as on lovely Earth. Transpired water vapor could be condensed and reused, and wastes from the crew would at least be partially recycled to the plants, the ecosystem’s primary producers.
There have been many attempts to construct small, closed ecosystems with light always being the key. For example, Clare Folsome sealed small aquatic ecosystems consisting of algae, brine shrimp, and other organisms (Basically the EcoSphere previously mentioned) in glass flasks. Although the flasks were prepared in the 1950s, some of them still retain fuctioning mini-communities.
Biosphere 2, at a cost of over 150 million dollars and covering 1.2 hectares of desert in Oracle, Arizona, stands in flagrant contrast to those relatively simple systems; including different types of “biomes”: ocean, freshwater and saltwater marshes, tropical rain forest, savanna, desert, intensive agriculture, and human habitat -in an attempt to mimic those of Earth. It didn’t work -oxygen and carbon dioxide levels fell, social problems arised, disaster ensued. Nowadays you can go visit it, piss around it and stuff.
As an interesting side-thingy; some economist used the cost per resident of the Biosphere 2 to calculate the monetary value of Earth’s biosphere.
Given that it does at least as good a job at sustaining humans as Biosphere 2, it should be worth at least as much per resident. This leads to a rather large, but finite, price of Earth itself.
So, Earth is worth at least ($240 M / 8 people) X 6.5 Billion people on Earth = 195 million billions of dollars.
Going back, I think such an attempt to mimic every single process on the Earth biosphere is flawed for our space explorations purposes. You only need to do the minumun necessary to make it work, no more, no less -just like politicians do; and it most assuredly works, because they keep on defecating on our faces and we keep on re-electing them.
Such were the ideals of the Bios-x projects of the Soviet Union. Bios-1, which, in 1965, reached 80%-85% closure with one Human in a 12 cubic meters area. Some suggested that traditional food plants, such as vegetables and wheat, be introduced into the system. To this end, in 1968 the Bios-1 sealed chamber was attached to a 2.5 x 2.0 x 1.7 meter chamber for higher plants and renamed it to Bios-2.
In 1972, Bios-3 was built in Krasnoyarsk, Siberia at a cost of approximately 1 million rubles (then, roughly equivalent to 1 million dollars), not counting the labor. It consisted of 315 cubic meters of space, sutiable for up to three Humans. They mainly used chlorella algae with artificial xenon lights to achieve a balance of oxygen and carbon dioxide. Water and nutrients were stored in advance and were recycled.
Bios-3 was used to conduct 10 manned closure experiments with one to three man crews. The longest experiment with a three man crew lasted 180 days (in 1972-1973). The total time of closure -that is, the time that one or more crew members have been sealed in one of the three facilities-exceeds one year.
I think small systems such as Bios-x are more productive for space exploration. It’s easier to stick them into a ship and it’s easier to build one on the surface of a planet (imagine giving a piggyback ride to 3000 species all the way to Mars, as Biosphere 2 proposed). Even so, Bios-3 only managed to achieve 90% closure -meaning, it will eventually fail, unlike mother Earth.
And we think we’re grand.
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