The whole point of a Cycler that just keeps to its standard orbit, is that it can be built (and expanded over time) to include massive shielding against solar flares and cosmic rays for the extended orbit it is in. No need to match orbital speed every cycle with Earth and Mars, so mass becomes irrelevant once put into that cycle orbit. The shuttles can do that matching planetary orbit speeds, transferring people and cargo at each end.
A shuttle would accelerate to match the cycler at one end, dock, the people could transfer to the habitat, and then at the other end, reboard the shuttle and match orbit with the destination; while a similar shuttle is loaded and fueled to do the same on the return trip.
If necessary, the Cycler could eventually include a spinning part to siimulate gravity. Note it may not need a full 1g; just enough to mitigate bone deterioration.
It seems a bit pointless to simulate anything stronger than Mars gravity on a cycler going to Mars. If you can’t adapt to Mars gravity on the cycler you may as well go home.
Sorry, I don’t have a cite - it was explained on one of the many science podcasts I listen to. I will see if I can re-locate it this weekend and post it. But I do remember that one of the issues was dizziness/nausea when turning your head, an effect you don’t get with real gravity.
I don’t know, The exercises they do on the ISS seem to put more stress on their bodies than 10% G would, and they still can’t walk when they get back. But I’m just guessing as well.
Right, but there is a world of difference between using resistance exercise to put your muscles and bones under strain for an hour a day and actually living in a gravity environment.
And if they were doing similar exercise in a 10% gravity environment, then they would do even more good.
Many of the issues seem to come from the body just not knowing which way is up. Fluid builds up in the eyes and brain, and all sorts of things that could be mitigated with just enough gravity to give a sense of direction.
And, as I said, eating and using the bathroom would be greatly simplified.
But, we don’t have any studies on any environments other than 1g and 0g. The astronauts were not on the moon long enough for there to be any real information about how they did there.
We should be building little centrifuges that we can put mice in, see how they react to different gravities, as well as how well things gestate in that environment.
Such proposals have been made, but I’m not aware of any that have flown.
That’s highly exaggerated. Astronauts are obviously unsteady when first getting back from space, and for safety reasons they tend to be carried out of the capsule, but they recover quickly. They can walk around normally after about a day. Sometimes quicker.
k9bfriender gives good reasons why exercises aren’t exactly a direct replacement for some level of gravity. They help keep up bone and muscle mass, but not much else.
We could be talking about a radius of hundreds of feet, maybe thousands. Would people notice this at all? Or even unnoticed effects? We don’t really know since it’s all an impractical thing to test here on earth. At some radius I think people should be fine, I don’t know how the 300 ft. radius previously mentioned was arrived at. I would assume a 300 ft. minimum and larger would be better. Much larger if people are going to be living in space. We could be talking about miles. Probably kilometers though, I think space will be metric. But the point of doing this would be to create vast areas that support food farming that would support human life on the space station plus more to help feed the Terrans. I assume food will grow much better in something less than 1G allowing the area at the 1G radius to be pretty large and hold a good sized population.
Solar flares are definitely a problem, but they are not even considered in the statistics I gave. The biggest issue is cosmic rays, which are omnipresent. It has been proposed to encase the spaceship in ice, but that would take 250 - 400 tons for the NASA version, which is smaller than Spaceship. There is a promising material but it hasn’t been proven yet.
Large rock collisions can squash a city also. A large habitat would have more time to patch a hole, and a real one would probably not have the empty wasted space of the O’Neill type of habitat. I heard O’Neill speak at Princeton in 1981 and I wish I were more convinced.
Nowhere in the movie (or the book as far as I can recall) did they say that the Discovery had a full g of gravity in the ring. Kubrick can be excused for not making it bigger since he built the damn thing. And, nitpick, 2001 was filmed in England. Kubrick was about the least Hollywood director I can think of.
Yes, good points. However, the astronauts are jogging and it is obvious they are close to 1G. Running in low G would look very different. (Of course, by running with the spin they increase their centrifugal force a bit.) Since the point about coriolis effects on the inner ear is barely known, Kubrick can be forgiven for glossing over it for visual effects. But yes, he was extremely fussy about verisimilitude compared to Hollywood. This was one of the first movies to try to realistically display space activity.
As I said, somewhere during a discussion of 2001 they mention that it would actually take a wheel 300 feet diameter to avoid coriolis forces messing with the inner ear. So someone, somewhere did either calculations or experiments. (I.e. see at what point coriolis forces create discomfort on a centrifuge, and extrapolate.)
True. That simplifies the size issue. As I understood, one of the problems is bones leaching calcium during weightlessness. So presumably even lunar gravity is better than none - although Heinlein in Moon Is A Harsh Mistress postulates that even an extended stay on the moon is not compatible with return to 1G. However, let’s agree that even lunar gravity is sufficient to reduce most of the medical issues, so we can put one colony there.
The probem with a roatating cycler module that is fully shielded - I recall something that about 6 feet of moon gravel would be decent shielding. So unless we want an heroically strong wheel, I suppose the rotating part would be inside a non-rotating external shield container so the shield does not need much structural strength.
My concern with those giant empty O’Neill cylinders is with the rare but not impossible chance of a meteor that creates a hole 10 or 20 feet diameter. That would be lethal for a city block of a modular habitant city on the moon, perhaps - but by the time someone could marshall the emergency crew to address a 10-foot hole (or an in-and-out) the air and most of the habitants and a lot of the contents would be sucked out. I’m not sure what sort of external shielding could protect against that. It just seems like an “eggs in one basket” scenario. I assume something like th 2001 space station would have pressure doors between segments of the ring, so most of it would remain unscathed.
I’m not convinced that Coriolis forces are as big as a problem as they’re made out. Humans are remarkably adaptable. It may be that a few days adaptation is enough to feel normal. It might not be a very pleasant few days, but moving around slowly and being generally careful would avoid the worst of the nausea.
The evidence for adaptability is limited, but so far points in the direction that high speed rotation isn’t a huge obstacle:
Recent data indicate that these earlier limits in rotation rate for eliciting Coriolis motion sickness are overly conservative. For example, Young et al. (2001) have recently shown that subjects can quickly adapt to motion sickness induced by rotation of the head during centrifugation at 23 rpm. Higher rotation rates permit a shorter radius to obtain a specified gravity level. Consequently, this result opens the possibility for a short-radius centrifuge within the space habitat to provide artificial gravity as an alternative to rotating the entire space vehicle.
There were experiments where they put people into centrifuges, and found that they got disoriented at certain RPM’s. They didn’t leave them in there for days, months, or years to see if they could adapt.
It would certainly help. Once again, there is no experimental data, but I would think that it would at least mitigate the damage done from zero g.
My proposal is to burrow into a small asteroid. Plenty of resources if we learn to use them. Build your rotating habitat inside of that.
That would be extremely rare. The hole punched in the habitat is going to be about the same size as what hits it, and there aren’t that many rocks of that size, comparatively, anyway. And if you have the technology to make an O’Neil cylinder, you would easily be able to see such a rock a long way off.
A ten foot hole also wouldn’t be as dramatic as all that, it would take hours or days for the atmosphere to reduce substantially, and anything more than a few hundred feet away would barely feel a breeze.
Finally, if you’ve built inside of an asteroid, then you have that shielding.
Blue Origin is working on seperating elements and making solar panels out of in situ resources.
If that works out, then it’s easy enough to build a bunch of solar panels on the outside of the rock you are burrowed into, and you can use the aluminum and oxygen liberated to fuel rockets to adjust the orbit.
Is there also a compelling argument for the individual?
It seems to me, you’d have to be out of your mind to seriously consider “colonizing” anything off planet.
What are you going to do except being bored out of your skull?
With a bit of luck, they might find some native tribesmen who, after their initial fear, would end up helping them. Who knows, they might even find turkeys.
Yeah, this is another area where the research is deficient. Of course we have plenty of data on humans in 1 g, and we’ve had humans in 0 g for over a year, so we have data on that, but the longest any human has ever spent in anything between 0 and 1 is the few days each the Apollo astronauts spent on the Moon.
Another option in low-but-not-zero gravity is for the astronauts to wear lead suits to bring their total weight up to the same as on Earth. That wouldn’t put exactly the same load on all of the bones and muscles as being on Earth, but it might be a good enough approximation.
Yeah, it might make sense for shielding. Maybe. The thing with shielding against cosmic rays, at least for the ultra-high-energy stuff, is that too much can be worse than not enough. Getting hit by an ultra-high-energy cosmic ray will break apart one molecule in your body. If that molecule is a DNA molecule, and if your body’s protective mechanisms fail to control that cell, that can cause cancer, but those are both big ifs, so it’s not too likely. But if your shielding gets hit by an ultra-high-energy cosmic ray, then the collision can result in thousands of energetic particles, which can do thousands of times as much damage to a body. To thoroughly protect against cosmic rays and their spallation products, you need shielding that’s ludicrously thick and heavy, all to protect against what would be a fairly minor risk if you instead minimized your shielding.
There’s also the risk of radiation from the Sun, but that’s easy, because it’s slow enough that you can see it coming, and you know where it’s coming from. Just make sure that your fuel tank is between you and the Sun when it hits.
Not necessarily. Once you’re in orbit and able to get to the vicinity of any other large body (like the Moon), you can pretty much do almost anything you want, with an almost arbitrarily small amount of energy, if you’re patient enough. Or rather, you’re still using lots and lots of energy, but you’re harvesting it from the orbits of other celestial objects.
There may not be a need to get entire asteroids closer to earth. Hopefully the valuable materials, mostly common metals to construct space habitats, can be mined out in the belt and only the product moved toward earth. Plenty far away from us still, but closer to the sun to take more advantage of solar energy and closer to us for faster communication with the robots from down here.
Not that it won’t be another cause for the nutcase CTs to entertain themselves with, but that will happen no matter what we do or don’t do.
Trying to survive? There would probably be lots of food production, oxygen production and habitat maintenance. And you you could catch up on your reading!
I assume that some percentage of the colonists are researchers, interested in the geology or chemistry of Mars, the moon, wherever the colony is located. There may be some advantage to astronomers of being there, so some are working to build or operate observatories.
Oddly enough, in 2001 the moon seems to have 1/6 g outside, when the astronauts are in their spacesuits, but inside, during the briefing scene, it looks like 1 g all the way.
It would be interesting to compute what size meteoroid would create such a hole, and its probability. Not very large, I’d guess. Plus, the hole wouldn’t be all your worries, since the rock would smash through a bunch of layers of the habitat also, and no doubt damage the infrastructure. All in all, I bet the probability of terrorism would be higher.
