Hey folks,
Years ago I saw a science-fiction illustration of an an asteroid that had been hollowed out and set to spin, meaning people could live on the inside surface a la Ringworld. This seemed like a nifty way to transport a lot of folks on a long-distance journey, but I wonder how realistic it is.
A few questions spring to mind about this scenario:
(1) In the illustration, there was an artificial “sun” in one end of the enormous chamber. Would something like that possibly be an effective way to light and heat such a large room? Granted the closest and farthest ends of the asteroid would probably be inhospitable, but could a sizable temperate zone be devised using only a single light/heat source? I know they’ve managed to pull it off on Earth, but then our sun isn’t permanently in one side of the sky.
(2) Could a large ecosystem exist in such a relatively small, closed system, without the benefit of weather patterns? This would (presumably) be like that Biosphere II experiment times a hundred.
(3) Wouldn’t the forces of accelerating and decelerating cause everyone to lean forward or backward as they walked around the place? Isn’t this a problem with any potential spaceship that wants to incorporate some kind of gravity mechanism?
I had an idea for a story based on this scenario but I’m really enjoying myself more just speculating on the logistics of such a ship.
Try to find Gerard O’Neill’s book “The high frontier, human colonies in space” if you can, or research his ideas online. The general consensus seems to be that he underestimated the practical difficulties in constructing such habitats, and overestimated the political will of the time to set out on such a project, but the notion itself seems to be sound. His idea was more of artificial structures, made from asteroidal or lunar raw materials, but using an asteroid as the fundamental structure of a space habitat is a common variant.
Depends on the size and shape of the habitat, but it seems possible. I don’t see the advantage in putting it at one end instead of the center of the habitat, though. That makes the center your ‘tropic region’ and the ends your ‘poles.’ To even it out you might put two smaller light-heat sources closer to the ends. Most often, the light source is based on a system of gathering sunlight from the outside and reflecting it inside.
Depends on how natural an ecosystem you want. I think it would be practical for relatively controlled farming and raising chickens and other small livestock. You’d need to set up sprinkler systems for rain, maybe use fans to force air movements, etcetera, and watch that the soil stays healthy, that there are proper parasites to break down biomatter and keep it fertile, and that no malignant fungus starts to spread etcetera.
I think these effects wouldn’t be too noticeable… you’d get used to weighing slightly more as you moved towards or away from the spin. A greater problem, in very small habitats, might be the space sickness of your head weighing slightly less than your feet (because it’s further towards the center.)
Hope this helps with your story and your speculation.
I think the OP meant that if you want to use this thing as a starship, you’ll need to give it a linear acceleration in addition to the rotation. Any practical starship drive will likely be continual-acceleration, which means one of two things. Either it’s a very low acceleration (say, 1/100 of a g), which is actually practical for a starship drive, in which case you just don’t worry about it (the “tilt” of the floor will be too small to worry about), or it’s a larger acceleration, in which case instead of making the inner surface a cylinder, you make it a stack of frustra of cones, with steps or elevators or whatever between them. So on any given cone, gravity would be more or less constant, and the floor would be more or less level. Of course, if you somehow have a strong enough propulsion system to maintain a constant 1 g, then you don’t bother spinning it at all, and just have “down” be towards the back of the ship. And you wouldn’t much want more than 1 g of propulsion, even if you had the tech for it, because there’s no way known to decrease the effective gravity.
Thanks for the responses. I guess a nice setup might be to have a light source at each end - greater and lesser - that pulsed opposite each other, to simulate day and night.
Also sounds like such a spaceship might be able to be somewhat automated, y’think? I ask because my story idea involved folks living inside who forgot or didn’t know they were on a spaceship at all.
The idea of having light coming from one end of the cylinder was basically a money/energy saving one, but it’s not applicable to a starship. The idea was to put a mirror at the end of the cylinder and reflect sunlight through a window into the interior. More optics (secondary mirrors or something) along the centerline of the ship would disperse the light somewhat evenly. Obviously, this won’t work for a ship in interstellar space, but will for a habitat in solar orbit.
You do realize that the idea that the passengers/crew of a generation starship forgetting they are on a ship is not especially new, don’t you. I hope you come up with a new twist to this sf cliche.
An asteroid converted to an interstellar vessel is used in Russell’s The Sparrow, if you’d like another story where the practical considerations are discussed. That one uses a constant linear acceleration as described by Chronos rather than a spin.
Also, it’s worth noting that planetary scientists argue about how many asteroids can be legitimately considered solid bodies of rock, versus gravitationally bound assemblages of smaller objects: clumps of gravel, basically. Reality is, some are one and some are the other, and there’s probably a range in between, but nobody knows for certain yet the relative proportions of the types. So it may or may not even be a realistic platform for construction.
Read John Lewis’s Mining the Sky for a detailed examination of asteroid makeup, according to our best information, and written for a lay audience.
Sorry, I should have prefaced that with “I know the premise has been done before.” Don’t worry, that’s not the twist of the story. I was just wondering how plausible it is.
Thanks for the added recommendations. It wouldn’t even have to be an asteroid really - could (and probably would) be built from scratch.
You might want to read “Rendezvous with Rama” by Arthur C. Clarke. Also Rama II by the same writer plus aurthor Gentry Lee. It covers a lot about what life would be like inside an giant asteroid or, in this case, something else!
The Night’s Dawn trilogy from Peter Hamilton heavily features inhabited asteroids and giant living space stations (in between descriptions of horrible violence and planets fully of drunken Irishmen :rolleyes: )
This was also the premise for the RPG Metamorphosis Alpha, where the campaign setting was a colossal multi-generation ship whose inhabitants had regressed to barbarism (and also mutated). Some of the earlier Might & Magic games have settings like that too.
For an excellent story about humans living inside of Halley’s Comet (story is inside Solar System, no internal light source like you’re envisioning), read Heart of the Comet by David Brin & Gregory Benford.
I enjoyed the book, but it was very different from what the OP is suggesting. The mission was to nudge the comet’s orbit to where it can be mined. They didn’t hollow out the comet, they just dug enough tunnels for a hundred or so people to live in. There was no artificial gravity (except a spinning excercise area, as I recall).
Anyway, I really don’t see why you’d make a spaceship out of an asteroid. If you spun it to simulate gravity, it would break apart. You could reinforce it with metal, but you still have a lot of rock that’s not doing much other than slow down the spaceship. Basically, it’s akin to hollowing a mountain on earth to make an apartment building. It’s far more practical to mine the asteroid, purify the metal and use it to construct a spacecraft.
Well, it sounds good, but the practical difficulties of making this plan work mean that no one has yet figured this out. What a lot of people forget about the Biosphere 2 experiment is that it demonstrated that we really don’t have the technology or know-how to make a large-scale, isolated, self-sustaining ecosystem yet. I think eventually we’ll figure it out, given enough time.
Correction: What it demonstrated was that the specific folks who made Biosphere 2 didn’t have the needed know-how. The biggest problem with B2 was that the concrete hadn’t cured completely, and was still absorbing oxygen. You can get around this problem just by waiting a bit longer after you build the thing. And you could probably get away with a much simpler ecosystem than Biosphere 2, if you don’t mind having to do maintenance on it.
Fair enough, but I think Biosphere 2 is the only example of such an isolated large-scale ecosystem. I would also mention that we don’t have the technology or know-how to create working large-scale ecosystems even if they remain in contact with natural ecosystems. I’ve worked in restoration ecology, and my experience with wetlands restoration has not given me faith in human ability to create (as opposed to augement) functional ecosystems (A cite to let you know what I mean). We really don’t understand enough to put together all the parts in an open system, so I have serious doubts about our potential ability to succeed in a closed system. That’s not to say we haven’t had some limited success (I’d certainly like to think my own projects have had some success), but we’re definitely still learning baby steps when it comes to creating sustainable systems.
The more I think about it, the more it seems that it’s virtually required that a generation ship in sf have the inhabitants forget they are in a ship. I can’t think of any stories where such a ship has gone for more than a few generations without this happening.
So maybe your twist should be that it doesn’t happen
Don’t worry, that’s not the twist of the story. I was just wondering how plausible it is.