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Thread: Orbital Habitats - A Flexible Solution for Humanity

  1. #31
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    I'd rather see the technology required to build a self sustaining colony developed and then see people go to mars and stay there, rather than spending the limited available funding on a short term expedition that may not be followed up in a way similar to apollo.

  2. #32
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    But you have to ask yourself: Why do you want to live in a safe?
    If you would enjoy going to live in a space station, why not join the submarine force and try it for 90 days....or so?
    It's one thing to talk about it from the hot tub with a glass of rose in your fingers and a BLt on rye. When your dinner comes out looking like toothpaste
    and you are drinking re-cycled water and breathing re-cycled air you may find that life in space may lose it's lustre real soon.
    We go into space when we have to....for brief periods, and do so at our immediate peril. Spaceship Earth is, after all, the best spaceship ever.
    Best regards, Dan

  3. #33
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    Quote Originally Posted by danscope View Post
    But you have to ask yourself: Why do you want to live in a safe?
    Because it feels cozy. I'm a city slicker. I love a densely packed metropolis where the horizon is UP. That's why my "dream habitat" is similar to an inside-out Coruscant.

    If you would enjoy going to live in a space station, why not join the submarine force and try it for 90 days....or so?
    An orbital habitat wouldn't need to be that small, thankfully.

    It's one thing to talk about it from the hot tub with a glass of rose in your fingers and a BLt on rye. When your dinner comes out looking like toothpaste and you are drinking re-cycled water and breathing re-cycled air you may find that life in space may lose it's lustre real soon.
    I already drink re-cycled water and breath re-cycled air. Dinner doesn't come out of a tube, but there's no reason to expect space habitats will be restricted to tube food.

  4. #34
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    Shuttle every three days?

  5. #35
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    Quote Originally Posted by danscope View Post
    Spaceship Earth is, after all, the best spaceship ever.
    Until it isn't, and we find we have no alternatives.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin

    Any technology distinguishable from magic is insufficiently advanced. Gregory Benford

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  6. #36
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    Even if Yellowstone blows it's stack completely, it will not remove all life on Earth. But it will kill...in a big way. However, life on Earth will always be easier
    than life in space. The problems in space in a confined environment are exponentially more difficult and those who venture in it are constantly at peril. No question. And there is a big difference between a "supported" orbital experiment....supplied with spare parts, materials, supplies and services, medicines and new crews........and just a space station.
    Best regards, Dan

  7. #37
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    Life in space will be more difficult, but many humans will do it anyway. We humans have a weird habit of living in some places just because we can. Look at Eskimos.

    It'll happen sooner or later (okay, later), and given the incredible potential resources available in asteroids and small rocky moons...someday extra-terrestrial inhabitants will outnumber Earthlings.

  8. #38
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    The ultimate advantage of planets over habs: Gravity. Our skeleton and circulatory system weren't built to float. All the logistical advantages of space habs over planets don't mean anything if you can't address the very practical reality that humans just weren't evolved to function in no-grav or low-grav environments.

  9. #39
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    Quote Originally Posted by Doodler View Post
    The ultimate advantage of planets over habs: Gravity. Our skeleton and circulatory system weren't built to float. All the logistical advantages of space habs over planets don't mean anything if you can't address the very practical reality that humans just weren't evolved to function in no-grav or low-grav environments.
    That's actually an advantage for orbital habitats. We don't know what the healthy range of gravity levels is, but we can certainly play it safe and rotate a space habitat to provide 1gee. But with a planet, you're more or less stuck with whatever you get.

  10. #40
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    Dan,

    With carbon nanotubes (dozens of times stronger than steel and weighs less -- 2.6 grams per cubic cm, to be precise),we can build them MUCH larger than a submarine. In fact, for a physically enjoyable experience in a habitat, it's MINIMUM radius of 224 meters (735 feet). Any smaller radius and rotation neccessary to maintain a pseudo-gravity of 1G will likely cause "dizziness, nausea, and disorientation" due to the corriolis effect. The fastest rotation allowable is about 2 to 3 rpm (SOURCE: http://en.wikipedia.org/wiki/Artificial_gravity)

    As for Coruscant-by-Earth (Issac's "Manhattan" on Page 1) and Ecotopia-in-orbit (filrabat's "orbital ecosystems" Page 1, POST #1 in fact)? That's not really an issue at all - other than debating material requirements for each type of environment. There's plenty of opportunities to create our own "Paradise in Orbit".

  11. #41
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    It'll happen sooner or later (okay, later), and given the incredible potential resources available in asteroids and small rocky moons...someday extra-terrestrial inhabitants will outnumber Earthlings.
    Soon, your passport will say "Earth-born" or "disporal".

  12. #42
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    Areas that need to be developed for truly self-sufficient habitats include maintaining stable artificial ecosystems (including minimizing loss), space mining (asteroid/comet/moons), processing and purifying materials in space, manufacturing the tremendous variety of parts needed, balancing rotational/centrifugal structures, and possibly repairing DNA damaged by excess cosmic radiation. Each of these will likely go through several stages of development using near-Earth stations before true colonization occurs.


    What about quarantine? Any new germ, bug or seed that gets into a closed-loop ecology could really mess up the hab's living situation. A "beaded" hab design --several independant units linked together-- would allow for plenty of compartmentalized redundancy.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin

    Any technology distinguishable from magic is insufficiently advanced. Gregory Benford

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  13. #43
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    Hi, The balancing of an orbital 2001 style space station is essentially fairly simple. The few primary commodities necessary in space are water, air ,
    food , and parts.
    That water will be carried in tanks. Those tanks, piped together comprise their own trim and drain system, just like will be found on any submarine.
    As more modules are connected to the station, they get piped into the system.
    The location and mass of each section will be carefully monitored.
    This is how you can rotate a large structure and have a smooth rotational capability. It's not that hard. When a person moves around to a different compartment, his weight is registered and noted by the central computer, and
    the trim system will pump water to the adjacent tank . Done.
    Yes, the water and trim system, like the people, have to be kept from boiling or freezing. But, that's a simple enough chore. Just buy the good heaters.
    You know.....the 'good stuff' .
    Best regards, Dan

  14. #44
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    Quote Originally Posted by danscope View Post
    Yes, the water and trim system, like the people, have to be kept from boiling or freezing. But, that's a simple enough chore. Just buy the good heaters.
    You know.....the 'good stuff' .
    That's good to know, thanks. I think heating won't be a problem; for most designs that allow sunlight in for growing plants, the problem is getting rid of excess heat.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin

    Any technology distinguishable from magic is insufficiently advanced. Gregory Benford

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  15. #45
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    I already pointed this out on another thread, but it applies here too; evenrything we will need to do to build real self-sustaining space colonies will have to be tested and retested in the field, which means in space. That is something we can do now, and aren't. And whether we start today, or in twenty, forty, or eighty years, we'll still have to go through the same process of learning how to make things work under the actual conditions that a permanent space habitat will face. If we don't go through this process now, someone else will have to go through the same process later. It's not something we can fully simulate on Earth, there are too many unknowns. That's what I'm proposing; that we start the process. I'm not saying we could just "throw a colony up there", but there are many things we can be doing using nothing but existing launch systems, that will be necessary, and are currently going undone. The early testbed model habitats can be located conveniently in LEO, they need not be full scale, just enough to work out all the kinks (of which there will no doubt be many). A LEO location also gives the test colonists somewhere to fall back to when things go wrong --and they will, prototypes are supposed to be tested to destruction. It's how we learn not to wreck them.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin

    Any technology distinguishable from magic is insufficiently advanced. Gregory Benford

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  16. #46
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    What makes you say we haven't already started? Many things can be tested on Earth, and we have been doing experiments to that end. Many things need to be tested in space, and to one extent or another every manned space program has represented some progress in that area. This includes various long term manned satellites, from Gemini to Soyuz to Skylab to ISS.

  17. #47
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    Quote Originally Posted by Noclevername View Post
    That's good to know, thanks. I think heating won't be a problem; for most designs that allow sunlight in for growing plants, the problem is getting rid of excess heat.
    Hi. You are certainly welcome. Take a very good look at Arthur C. Clarke's
    Space Station, for you will see the future.
    Best regards,
    Dan

  18. #48
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    Quote Originally Posted by IsaacKuo View Post
    What makes you say we haven't already started? Many things can be tested on Earth, and we have been doing experiments to that end. Many things need to be tested in space, and to one extent or another every manned space program has represented some progress in that area. This includes various long term manned satellites, from Gemini to Soyuz to Skylab to ISS.
    Not at nearly the rate that was and is possible. I do appreciate that progress has been made, but mainly geared towards extended missions in space, not permanent living conditions.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin

    Any technology distinguishable from magic is insufficiently advanced. Gregory Benford

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  19. #49
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    One of my favourite designs is the open ring, which could (in theory) be built up to 2000 km in diameter if the outermost layer is made of carbon nanotube.
    Larger versions, such as the Halo, Iain Bank's Orbitals, and Larry Niven's Ringworld, all require materials stronger than anything known to be physically possible.

    Here is Forrest Bishop describing the 2000km version
    http://www.iase.cc/openair.htm
    here is a method of illuminating them (pdf)
    http://www.orionsarm.com/whitepapers/SpaceRings.pdf
    and here is a page with a few images I have made of them
    http://www.orionsarm.com/worlds/Arkab_Prior.html

  20. #50
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    We might start with smaller, more mobile habs, that way it's easier to dodge any large debris (or intentionally aimed projectiles; there's always going to be dangerous people, even in space). It also allows the colonists to go where the resources are, if necessary.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin

    Any technology distinguishable from magic is insufficiently advanced. Gregory Benford

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  21. #51
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    Quote Originally Posted by eburacum45 View Post
    One of my favourite designs is the open ring, which could (in theory) be built up to 2000 km in diameter if the outermost layer is made of carbon nanotube.
    The big problem with an open ring is that the air will spill out unless the structure is almost perfectly rigid. Imagine unrolling the ring so that it's a flat trough with gravity pointed downward. What happens if the trough sags? The fluid inside will spill out, except for a little bit at the bottom of the sag.

    The same thing will occur to the ring, when it slightly distorts into an oval shape.

    You can theoretically mitigate this effect by partitioning the ring into tall "buckets". The individual "buckets" can be tilted by a significant angle and still hold in the air. However, it would require less material to simply put a roof on the top--and such a roof would practically eliminate air loss altogether. (With any sort of open design, some air will leak simply through brownian motion.)

  22. #52
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    Even Niven's Ringworld, with its thousand-kilometer Unobtanium walls, still had some air loss.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change. Charles Darwin

    Any technology distinguishable from magic is insufficiently advanced. Gregory Benford

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  23. #53
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    Habitats are full of air.

    Quote Originally Posted by filrabat View Post
    Dan,

    With carbon nanotubes (dozens of times stronger than steel and weighs less -- 2.6 grams per cubic cm, to be precise),we can build them MUCH larger than a submarine. In fact, for a physically enjoyable experience in a habitat, it's MINIMUM radius of 224 meters (735 feet). Any smaller radius and rotation neccessary to maintain a pseudo-gravity of 1G will likely cause "dizziness, nausea, and disorientation" due to the corriolis effect. The fastest rotation allowable is about 2 to 3 rpm (SOURCE: http://en.wikipedia.org/wiki/Artificial_gravity)

    As for Coruscant-by-Earth (Issac's "Manhattan" on Page 1) and Ecotopia-in-orbit (filrabat's "orbital ecosystems" Page 1, POST #1 in fact)? That's not really an issue at all - other than debating material requirements for each type of environment. There's plenty of opportunities to create our own "Paradise in Orbit".
    Hello FILRABAT

    Note that an spherica lhabitat with the minimum radius of 224 meters wil have a volume of 45,000,000 M3

    With a M3 of air having a mass of 1.3 Kg you will need a minimum of 58,000 metric tons of air to fill your habitat.

    For a O'Neil structure with Km3 of inside space you will need millions and millions of tons of air.

    Where to find it ? How to process it , to transport it ?

  24. #54
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    galacsi,

    I didn't do calculations on a sphere of that size, but you're probably right about the area.

    Actually, I'd much rather have cylinders or rings than spheres. While spheres do have lower material requirements, their pseudogravity decreases fairly quickly away from its equator - especially one with only a 224 meter radius. I don't know the precise math for determining the Gs at the 40 deg latitude of a spherical habitat, but it's bound to be noticeably lower than 1G. For example, here on Earth (close enough to a true sphere to not substantially alter the rotation speed per latitude data), one degree of longitude at the equator is 111 km. At 60 degrees, it 55 km while at 30 degrees it's about 90 km (I grew up at 32.75 N, so i know that :P). The poles, of course, are 0.00 km.

    With that steep a pseudogravity change over a 351 meter distance (pole to equator), that'll hugely reduce the useable area of the habitat if we wish to continue living in the 0.9 to 1G range (which I'd want to, otherwise the lower G's will likely confuse our motor coordination substantially). Even though we can mark of pseudogravity boundaries with fences, that still won't solve the "useable are per G" problem. With a cylinder or ring, you don't have that problem. If you desire gravity options, simply build another ring outside the existing ring, then speed up or slow down the rotation as its appropriate.

  25. #55
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    A spherical outer shape doesn't decrease the total usable living area significantly. A cylinder needs to have sidewalls anyway, and the most efficient shape for these sidewalls are rounded caps. The end result is something which is similar in shape to a sphere anyway.

    Of course, a cylinder can theoretically be made long and thin, to minimize the end cap area. However, this results in an unstable colony which needs active control and compensation. Otherwise, the colony will end up spinning end-over-end.

  26. #56
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    Where to Find Habitat Materials

    Quote Originally Posted by galacsi View Post
    Hello FILRABAT

    Note that an spherica lhabitat with the minimum radius of 224 meters wil have a volume of 45,000,000 M3

    With a M3 of air having a mass of 1.3 Kg you will need a minimum of 58,000 metric tons of air to fill your habitat.

    For a O'Neil structure with Km3 of inside space you will need millions and millions of tons of air.

    Where to find it ? How to process it , to transport it ?
    One word, Galacsi --- V-E-N-U-S

    That promises to be the one-stop shop of habitat construction, given its 96% CO2 atmosphere @ 93 ATMs. Think of how much carbon we can acquire for the nanotubes, not to mention oxygen for the habitat atmosphere (further not to mention other uses of that O2 split from the carbon!). Even better, Venus it's atmosphere is so massive that even small percentages of other gases yield plenty of absolute masses of that gas (three times as much Nitrogen by mass that Earth's atmosphere). Heck, there's even enough water vapor remaining to supply a decent amount of water for several huge habitats. If the water runs out or gets prohibitively expensive to extract? Use the Sulfuric Acid (H2SO4) to get water and sulfur dioxide! Sulfur itself has a large number of uses.

    Need silicon for some reason? Build high-temperature tolerance robots at the surface to send it to the floating balloons 25 km above the surface!

    Needless to say, this is for at least a century in the future. I'm simply looking long term. Regardless, expect Venus to be "The Workshop of the Solar System" in a few centuries.

    As for the near-present -- well, it's inevitable we'll have to get the carbon, O2, N2, H2O, etc, from Earth (for the most part, at the very least). But it should be enough to get us started.

  27. #57
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    Venus has a deep gravity well, and a thick atmosphere. It's easier to get stuff from Earth than from Venus (especially with the Moon around to play gravity maneuver tricks with). I do like the "aeroscoop" concept, but this is limited to scavenging stuff from the upper atmosphere. That means just carbon and oxygen, I think.

    I have higher hopes for harvesting moon material in the Jupiter or Saturn systems. Jupiter would be better for solar and/or tether power, but Saturn lacks Jupiter's annoyingly intense radiation belt. The distances involved in the Saturn system are a lot smaller and more manageable than Jupiter's vast system.

  28. #58
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    Quote Originally Posted by IsaacKuo View Post
    A spherical outer shape doesn't decrease the total usable living area significantly.
    What about the area with the same gravity range as Earth (0.9 to 1.1 G)? I think that's the healthiest long-term gravity for we humans, given that we evolved in it. Certainly we can live in lower and perhaps somewhat higher G's, but we aren't adapted for it.

    Of course, a cylinder can theoretically be made long and thin, to minimize the end cap area. However, this results in an unstable colony which needs active control and compensation. Otherwise, the colony will end up spinning end-over-end.
    Much less likely if the length = 2r (same as length = diameter). In fact, if you assume a "Lego blocks" building model instead of buiding a whole solid shell from the get-go, you can add both circumference and cylinder length at the same time. It also allows habitation of a partially completed outer shell. In fact, we could begin human habitation of the habitat much quicker - for we won't have to wait for completion of the whole orbital for habitation to begin.

  29. #59
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    Quote Originally Posted by IsaacKuo View Post
    The big problem with an open ring is that the air will spill out unless the structure is almost perfectly rigid.
    --- (With any sort of open design, some air will leak simply through brownian motion.)
    Bishop's original design had transparent, non-loadbearing, slightly spherical endwalls made of plastic just to stop leakage. I haven't modelled them, as I like to see the surface of the ring, but they should be included. Many plastics would degrade in ultraviolet light near a star, so perhaps the material for this transparent endcap would be a problem.

  30. #60
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    Quote Originally Posted by filrabat View Post
    What about the area with the same gravity range as Earth (0.9 to 1.1 G)? I think that's the healthiest long-term gravity for we humans, given that we evolved in it. Certainly we can live in lower and perhaps somewhat higher G's, but we aren't adapted for it.
    That is not necessarily the case. Humans are upright bipeds, a very unusual bodyplan, and over time a very large proportion of us develop back problems. With a slightly lower gravity I think a lot of those problems might be more manageable.
    The rings in OA often rotate to give a gravity of 0.8 gee, which is a fairly arbitrary compromise between full gravity and low, moon-like gravity. A slightly lower rotational speed could help reduce certain gravity-stress related illnesses.

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