Now as I understand it, in a typical O'Niel design one end of a colony cylinder end would face the sun and light would be reflected through huge windows with large mirrors. This prevents anyone from having to move their book in a circle to read it. It seems to me all that window area is going to waste and that with artificial lighting the entire interior area of the colony could be used for habitation. A diamond window at the end of the cylinder facing the sun could let light in from the side and the inconvenience of this sideways light could be reduced by having the ground slope up to the far end of the cylinder so everything won't be in shadow. Mirrors and piped sunlight could overcome the problem of sideways light, but artificial lighting might still be easier.

Having the endcap transparent in the middle and opaque around the edges, then putting a structure along the axis holding angled mirrors, would allow you to direct sunlight along the entire inner surface with no sideways Sun.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

No doubt all of these variations will be tried over time.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Before there are permanent orbital habitats, there will be smaller, longterm test beds. Probably including some on the ground. What criteria, other than actually being in space, would have to be met for a truly comprehensive test of the concept?

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Hi, If you are talking about an habitat, there are two styles:
1. Re-supplied on an regular basis ..........and

2. A completely self- sufficient ...grow your own food thing .

Habitat one we already have. Nuclear Submarines scrub their air and are
reasonably self sufficient for the length of their patrol . Operations like ISS and
Salyut 1, Skylab all do the basics . But they are on an umbilical chord from which they depend.
We should like to get towards # 2 . It will get interesting.

Best regards, Dan

They tried to do that here in Tucson (Biosphere 2) but it turned into a farce . . .

http://en.wikipedia.org/wiki/Biosphere_2

What I'm asking is, how would you do it right? Assuming you can find people willing to spend years if not decades inside one.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Biosphere 2 could have been done right.

ETA . . .

From the same wiki article:

It depends on your purpose. For instance, if you are focusing on biological recycling, or are going with more mechanical with biological. Or if you are working on a spacecraft system (highly mass constrained), a Mars colony (which has access to extra water, carbon dioxide, nitrogen, etc. so some constraints are looser), or a large space habitat near Earth (not terribly mass constrained, with tighter constraints on supplements than a Mars colony, but closer to Earth if there are problems).

In general, I would do a lot of experiments, but grand demonstrations would come much later. Do keep in mind that there have been real experiments, though they tend to be focused more on spacecraft systems.

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Hi, Clearly, we are not going to constrain mass to a design for interplanetary
transport. We have to develope systems that can simply survive in LEO for an extended period of time....say two years. At least in LEO, you have the probability of a supply ship from Earth at distant intervals, and if a severe threat
comes up. The 2001 space station seems properly qualified for success in this endeavour.
Building something too small ensures it's failure and demise.

Best regards, Dan

So again I ask: How would you design such an experiment?

Should I move this to its own thread as a separate subject?

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Hi, The real question is ...." How will you fund this space station?"
Then, depending on who supervises the " Committee " , you will possibly get
an experiment worthy of the money required to fund it, and the capability to
accomplish those missions in LEO which we need and seek. Now you can test the longer term space worthyness of such systems in the real situation.
Having separate cells ...as in the 2001 wheel system, allows you to try different systems simutaneously without interfering with other experiments.
This allows for flexibility.
Clean air, food and gravity. Sounds simple.
Best regards, Dan

But not the one I asked, and have yet to see any answer.

...Yes, designed how?

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

As you all know well, I prefer using rather low-tech approaches, although I appreciate that techno-based solutions will be inevitable, especially for the earliest models of space habitats.

Personally, I'd start by testing two kinds of systems, based on their air and water sustaining systems:

1. Purely artificial (i.e. machines alone regulate the level of O2, CO2, N2, H20, etc.

2. Purely Natural (i.e. purely from plants and small animals existing in the system)

Even the simplest #2 -- using only small, sterilized herbivorous mammals (mice, herbivorous birds, etc) is going to be very complicate. You need the following:

a. high-O2 producing plants
b. Animals producing enough CO2 to sustain the plants

That alone takes care of the Atmospheric mix requirements. This is not nearly enough though.

c. Liquid water source - in a purely natural system, it won't rain (at least not in any way I'm aware of). That translates into no water for either plants and animals

d. Food source for the animals - we also need to make space for food sources the animals naturally eat. We certainly don't want them eating the high-O2 producing plants (that alone is enough to cast doubt on the reliability of animal experiments in the smallest experimental habitats - humans, after all, WILL know what plants not to touch, even if we are partially herbivorous).

e. Probably other factors I haven't thought of yet.

So in the end, I think it's more efficient experiment with human-habited ecosystems from the start; for it'll give us a more reliable picture of what will happen than animals without any clue whatsoever their purpose for living is.

I think the optimal solution, both the most efficient and the safest, will be a combination of biological and technological means to sustain an appropriate air, food, and humidity environment. If one system breaks down, the other can compensate as a backup (at least for the early, experimental stages of habitat formation...which will undoubtedly take place in LEO)

I'm surprised that the ISS doesn't have a module who's sole purpose is to grow food for the station.

Note that humans are animals. The amount of CO2 plants need to generate enough oxygen for one human is equal to the amount of CO2 one human generates.

Also note that plants don't really need us animals around. They generate CO2 through their own respiration. If they "run out" of CO2, then they stop growing, but they'll still live. If animals aren't eating them, then they don't really need to be growing to replace lost tissue.

And if animals aren't around, then there's a limited supply of organic nutrients anyway. Plant growth will be limited by either CO2/water or nutrients. Once the supply limit is reached, no more growth is possible. It's only when animals are around that plant tissue gets eaten and converted into nutrients, CO2, and water.

The plants can be aquatic, so they're literally surrounded by water. Cyanobacteria and algae don't need rain.

There's nothing inherently wrong with the animals eating the oxygen producing plants. That's how the Earth's biosphere works. All that's required is to make sure the plant growth potential exceeds the rate at which the plants are being eaten.

Even if you should (for some reason) need to rapidly increase the CO2/O2 ratio, you could simply use non-biotic means such as (carefully!) controlled combustion.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

And I say again: It depends on your goals. Keep in mind that there have been a good number of experiments, such as the Russian experiments (some with people) for semi-biological long term support for space travel.

__________________
I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser