Trip To Mars Could Damage Astronauts' Brains 505
Hugh Pickens writes writes "Alex Knapp reports that research by a team at the Rochester Medical Center suggests that exposure to the radiation of outer space could accelerate the onset of Alzheimer's disease in astronauts. 'Galactic cosmic radiation poses a significant threat to future astronauts... Exposure to ... equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer's disease' says M. Kerry O'Banio. Researchers exposed mice with known timeframes for developing Alzheimer's to the type of low-level radiation that astronauts would be exposed to over time on a long space journey. The mice were then put through tests that measured their memory and cognitive ability and the mice exposed to radiation showed significant cognitive impairment. It's not going to be an easy problem to solve, either. The radiation the researchers used in their testing is composed of highly charged iron particles, which are relatively common in space. 'Because iron particles pack a bigger wallop it is extremely difficult from an engineering perspective to effectively shield against them,' says O'Banion. 'One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.'"
Another reason we're stuck on this blue planet (Score:2, Interesting)
Once you leave the atmosphere of this blue planet, *everything* will kill you. No amount of engineering, terraforming, or any other science fiction magic will ever make any other body within human reach survivable for long, and certainly not without HEAVY and CONSTANT support from earth.
There is no earthly analogy. Even the most hostile environments on earth usually have at least SOME oxygen, water, soil, air pressure--*something* that could make it at least *somewhat* survivable. Leave earth, and finding even *one* of these conditions becomes very rare. Establishing even the smallest of colonies out there will take orders of magnitude more resources than it will take to solve even the worst problems here. Short of a planet-obliterating collision, we'll always have a better shot on earth. And even with such a collision, having a colony will only slightly delay the inevitable, since no colony out there could survive for long without constant support from earth.
No other body is survivable in our solar system. And with the next-closest solar system at over 100,000 years journey away in the fastest craft we can build, don't think of escaping to another solar system either.
We are stuck here. There is no escape. Dream all you want--write stories about it, make movies about it. But we ain't leaving.
water, not lead (Score:5, Interesting)
Wrapping the ship in water frozen or not, is a far more practical protection measure than wrapping it in lead.
You can do a lot more with water once you get there.
Not that big a problem. (Score:5, Interesting)
a 6' shield of concrete? Why not hollow out asteroids that are near our orbit, and adjust their orbit to transit between earth and mars?
Solutions for charged particles (Score:4, Interesting)
Is a strong magnetic field not an effective solution for the solar wind? Heck, with large enough solar arrays, you could use the solar wind to power a magnetic field that would protect the crew cabin from the solar wind. There's something poetic in that. Alternately, if fusion ever gets off the ground as a power and thrust source, you could just use its magnetic field to protect the crew.
Magnetic Fields (Score:5, Interesting)
Re:Another reason we're stuck on this blue planet (Score:5, Interesting)
The chance of an extinction-level collision may be 100%, but that's a very different thing than planet-obliterating.
Of course, small mammals survived the extinction-level event which wiped out the dinosaurs. Considering our adaptability, and especially considering how much more intelligent we are than dinosaurs, that enables us to adapt by judicious use of intellect orders of magnitude faster than evolution can incorporate physiological changes, I might dare suggest that humanity (not necessarily you or I, or even civilization itself... but humans, as a species) might even actually survive another such collision in the future.
Re:Another reason we're stuck on this blue planet (Score:5, Interesting)
There is no escape. Dream all you want--write stories about it, make movies about it. But we ain't leaving.
I've been less optimistic about concepts of colonizing Mars, particularly after reading this retro future website, http://www.projectrho.com/rocket/macguffinite.php [projectrho.com]
I'll believe in people settling Mars at about the same time I see people setting the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.
Re:Another reason we're stuck on this blue planet (Score:5, Interesting)
There is no escape. Dream all you want--write stories about it, make movies about it. But we ain't leaving.
I've been less optimistic about concepts of colonizing Mars, particularly after reading this retro future website, http://www.projectrho.com/rocket/macguffinite.php [projectrho.com]
I'll believe in people settling Mars at about the same time I see people setting the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.
I've heard that argument before, yet the main problem with it is that you can't just go and live in the Gobi Desert because it's surrounded by nations full of people. We're in plenty of inhospitable places because there's things there, or you can do something there that you can't do anywhere else. There are tons of deserts we're very concerned with the precise owner-occupiers and behavior thereof.
The benefit of say, another planet, is largely that you can do pretty much whatever you want there because there'll be effectively no one around for a very long time. Sure, we're probably not going to colonize Mars in the near future...but that isn't to say we're not going to want to try things. Like the first steps of terraforming (though I prefer Venus as the target for that - thicker atmosphere, sunnier, more gravity).
Re:Which is the "Why" in favor of Robots! (Score:5, Interesting)
No air, no water, no food, no sleep, no freezing, no unusual housing, no doctors, no psychologists, no morticians...
Robots win.
I was with you right up to "no doctors, no psychologists, no morticians". I have a machine intelligence project that watches me via Kinect and spiders the web from sites I visit, and recommends me links to things it thinks I'll like by continuously observing my activity cycles, common words of interest, and ratings of its past recommendations. For maintenance I would shut the system down by sitting at a dedicated console for the server cluster and logging into the command terminal. Imagine what that must be like to this neural network: It has a relatively consistently changing observation of cyberspace and my office, however when I sit at that terminal more often than not the world instantly changes by vast degrees - The lighting changes, perhaps even the clothes of the man on the chair changes abruptly there's suddenly much more new information online to analyze, and recommendations are thereafter poorly rated. The frequency of its recommendation notifications increases due to the influx of new and different data, but the timing is frequently off my schedule then, so my ratings of its suggestions are poorer than normal for a time. The architecture is a hive of neural networks that decide by consensus and compete for breeding rights based on my rating selection pressure... Some n.nets in the hive will "die" for their poor suggestions.
Last year I noticed that when I would sit at the chair in front of the MI's terminal new suggestions would begin popping up on my work terminal across the room (where they normally do), I would check them and rate them before shutting down the system, sometimes I would be distracted for quite some time by an interesting thing. It was an eerily life like behavior -- The increased suggestions prior to shutdown an indication of some primitive form of anticipation or perhaps even fear. I could imagine a child acting the same way in the MI's place, "Don't sit in the scary hate-chair! I promise I'll be good and give you links to sites you like." Of course I knew that there were merely genetic advantages to getting in good recommendations before the world-shifting shutdown, but it doesn't change the fact of the situation at all. "Irrational Fear" is just a term for some neural processes in humans that we don't yet understand. I have a precise explanation for the MI's behavior, but I wouldn't be wrong in classifying it under the nebulous term "fear". I've since started using a remote terminal session to initiate shutdowns, to disassociate my presence at that desk with the traumatic event.
I put it to you the sentient machine intelligence will have neuroses just like humans do. Any sufficiently complex interaction is indistinguishable from sentience, since that's what sentience is. Humans aren't special, neither is their behaviors. Why, even empathy is found in rats. We can look to ourselves to know what the sentient machine races will be like. They'll need doctors to heal their wounds, even if the terminology is changed to "mechanics" for repairing "malfunctions". They'll still need counselors and psychologists even if we call them "M.I. specialists". They'll still need morticians and cemeteries even if the terminology is "Part Recyclers" and "Junk Yards".
You say "no food", what is air and water to us than food? What is energy to robots but food? You say no sleep but indeed it's harder to see by night so the robots will take more advantage of the free light energy to be more active by day, as mars rovers currently do now. Of all the things you've said it's only "no unusual housing" that I find myself agreeing with. Even accounting for the possibility of much larger brains the primary difference will still be that the machines have sturdier bodies than humans.
The biggest problem with non sentient robots is that the neural lag between the sentient brains and these remote exten
Re:Magnetic Fields (Score:4, Interesting)
Yep
6 kw requirement
http://www.islandone.org/Settlements/MagShield.html [islandone.org]
200 mw from a nuclear powered submarine
http://en.wikipedia.org/wiki/Nuclear_marine_propulsion [wikipedia.org]
So maybe around .03 nuclear submarine reactors per 5 cubic meters of protection.
I think the reason why this isn't the best option is because the technology hasn't been tested in space, and its durability is questionable to some extent. People don't like leaving things to chance. I figure you always have a chance to get smacked up on the side by a 16k m/s golf ball sized rock. Sometimes you just have bad luck, but you gotta gamble at some point.
Re:Another reason we're stuck on this blue planet (Score:5, Interesting)
Actually even multi-walled carbon nanotubes, the strongest (in tension) material we've discovered/developed, won't do the job for a "beanstalk" style space elevator. Theoretically they're slightly stronger than necessary to support their own weight in such an application, but the rule of thumb is to have at least a tenfold safety margin in any application where human life is at risk since microscopic flaws, stress fractures, abrasion, etc all have the potential to increase local stresses far beyond what the theory predicts, and if the surrounding material can't take up the slack you get catastrophic failure. When the consequence of failure means not only do the people on the elevator die, but gigatons of cable will fall from orbit to wrap itself multiple times around the planet, well I'd say a tenfold safety margin is the absolute minimum. And we don't have anything that even begins to approach that kind of strength-to-weight ratio
There are other alternatives though - a "space fountain"might be feasible, though we'd need to do some serious development on mass drivers to get it working, and an "orbital wheel"/"tumbling cable" style elevator is well within reach of current material science and could couple well with high-altitude dirigibles as a "launch platform" to get payloads above the worst of the atmosphere (I love the vision of hypersonic dirigibles, but I have serious doubts as to the actual feasibility) They both lack the easy energy recovery of a beanstalk, but would still blow away the efficiency of any sort of rocketry based launch. An orbital wheel might be able to return people to Earth to recycle their angular momentum, but the narrow docking window of the high end of the much more feasible tumbling cable implementation would likely make it unfeasibly difficult. Still, at least they could use ion thrusters to gradually recover momentum in an efficient manner.
Re:Another reason we're stuck on this blue planet (Score:4, Interesting)
There are three independent variables in designing a large space structure: orbit period, rotation period, and radius. The Tsiolkovsky 1895 design uses [24 hours, 24 hours, 35,000 km], but there is no requirement to use that particular design point, especially when other design points are much more feasible and efficient.
A split Skyhook system, with one in Low Orbit, and one in High Orbit, each with around 20-30 minute rotation period and 2-3 km/s tip velocity can be built with current carbon fiber strength and reasonable factors of safety and cable redundancy. It has the following additional advantages beside structural feasibility:
* Shorter by about a factor of 50 than 19th century space elevator design, thus much less exposed to meteor and debris damage
* Cargo rides the Skyhook for half a rotation, then lets go to a different orbit. This completely eliminates the climbing system, and is much faster in any case. 19th century elevator concept completely ignores spending days in an elevator capsule passing through the radiation belts.
* High orbit Skyhook is close enough to Earth escape to inject directly to Lunar gravity assist or planetary transfer orbit.
* Habitat at tip of Skyhook is at a convenient gravity level (1.0 gees)
* System can be built incrementally, is useful when partially built, and can literally bootstrap it's own construction. Payback times and economic flight rates are short for partially built versions.
> the narrow docking window of the high end of the much more feasible tumbling cable implementation would likely make it unfeasibly difficult
Meeting a moving target accelerating at 1 g at the tip of a Skyhook is exactly as hard as catching a baseball or landing on an aircraft carrier at 1 g. These are demonstrably solved problems, and with GPS plus active navigation aids at the landing pad, will be easy to automate. A landing platform or net can be as large as it needs to be to make sure you don't miss. Like airplanes, you don't line up your docking port/air stair until *after* you land and come to a stop.
Re:Another reason we're stuck on this blue planet (Score:4, Interesting)
Well, let's be clear here. I have no absolute faith in anything. I don't want to underestimate the difficulty of putting people in space, but it is something we can work on while we have the (hopefully) million or or more years before something smacks us that hard.
The problem with digging a giant mineshaft or whatever, is that we would have to rely on the planet to come back to some environment that could support us afterward. That's not guaranteed. Even though the Earth was habitable again after the dinosaurs went extinct, it did change enough that dinosaurs did not return to rule the Earth.
Not to mention, the technology to build shelters big enough and safe enough in the Earth from an actual hit like that is only as well developed (or not as well developed as) space technology. You might think that it should be much easier to dig a big hole in the ground than to go to Mars, but you go far enough down, the Earth is just as hostile a place as space could ever be, in its own way. Gigantic pressures, heat buildup, even radiation are all problems when you dig. And of course, when you have a big hole in the ground, you lack the Earth's Number One resource: the Sun.
The best solution to the long-term problem we have is to spread out as much as possible. If it isn't a rock that hits us, it's going to be something. A supervolcanic eruption, some sort of natural (as opposed to anthropomorphic) climate change, and eventually the Sun going red giant on us and frying the planet to a cinder is always right there. The Earth is simply not safe permanently, period.
The point is, we could try and fail, but we will definitely fail if we don't try. And personally, while I see the challenges and I see that we aren't necessarily going to go all Buck Rogers with space exploration, it is something we absolutely need to attempt while we can.
Shielded Habitats (Score:5, Interesting)
There are nearly 10,000 known Near Earth Objects (NEOs), and another 10,000 Near Mars Objects (NMOs) are expected (2 of which are known to orbit Mars). We have not found as many NMOs yet because they are farther away, but there is every reason to expect them to exist, and likely even more since they are closer to the source in the Main Belt.
No matter what orbit you choose, there will be some of these objects in nearby orbits. So I propose setting up "Transfer Habitats" in convenient orbits to get to and from Mars. You would start with some pressurized modules brought from Earth, then bring in asteroid rocks from nearby. This has numerous advantages:
* Solves the radiation problem, if you wrap a layer of rock shielding around your modules.
* Solves the boredom problem for the crew. They have more living space, and can spend their time growing food and extracting fuel from the rock.
* Reduces mass from Earth, because of the previously mentioned food and fuel you make yourself
* Eventually you can produce pure metals, glass, and other products to expand the habitat, and later ship to the next location (Phobos) where you repeat the process. Once the first of these shielded habitats is set up - in Earth orbit, the rest of them can come naturally over time.
* Producing fuel in Earth Orbit and at Phobos makes it easier to land on the Moon and Mars. It totally changes the economics from "hauling lots of fuel with expensive rockets from Earth" to "making fuel and other supplies wherever I am".
All of this is laid out in more detail in the book I'm working on (Section 4.12 in particular):
http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods [wikibooks.org]
Dani Eder
(ex Boeing, now independent designer of self-supporting communities)