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Study shows space travel is harmful to the brain (phys.org)
39 points by iProject 1753 days ago | hide | past | web | 19 comments | favorite

>The round trip to the red planet, in particular, could take as long as three years.

That "up to" is technically correct, but seems pretty misleading. I don't think anybody would seriously propose such a trip.

Per wikipedia (http://en.wikipedia.org/wiki/Manned_mission_to_Mars#Windows)

>However, typical Mars mission plans have round-trip flight times of 400 to 450 days.[14] A fast Mars mission of 245 days round trip could be possible with on-orbit staging.

And of course if you are only interested in a one-way ticket (obviously with a drastically changed life expectancy when you arrive) then you are only looking at a trip in space of a few short months. (I think in theory you can get down to 88 days to Mars with the Aldrin Cycler, for example).

No part of going to Mars isn't going to likely kill you, either nearly instantaneously or slowly. Mars missions are going to create a lot of bodies. I'd love to be proved wrong there, but that just seems to be the reality of anything we can do in the foreseeable future. This risk is understood though, nobody who has seriously considered going for it is unaware. You may as well write articles on the dangers of BASE jumping.

In 1893, when there was no consensus whether there might be sea or land around the north pole, the polar explorer Fridjof Nansen had a theory that there is only sea, and that the currents flow the ice over the polar region from Eastern Siberia, over the pole, towards Svalbard and Greenland.

So he set up an expedition, 12 men and food for 5 years, sailed north of Eastern Siberia and deliberately stuck the ship in the ice. Then waited ...for 3 years, and yes, finally emerged from the ice on the other side, near Svalbard.


I dunno. NASA has pulled off some ridiculously long odds in the past, and I'm always amazed at how low the body count of manned missions to the moon is. (Apollo 13 was nothing short of a miracle, even all Hollywood interpretations aside).

I think that so long as no one attempts a mission to Mars before they're actually ready to do so, we'll be alright.

If get bored after a few missions and don't go back, then we might pull off a low to no body count. But the more missions we do, the more those unavoidable risks start to stack up. If we actually start getting up to "colony" scale, my money is on there being a decent bodycount, regardless of any herculean precautions.

Throughout the history of man, people have jumped into the unknown abyss, wondering if they would ever return. Today, we have lots of evidence that somebody might or might not return, but if nobody jumps, we will never cross the abyss.

I hope people continue jumping.

Let's hope the Martians fare better than the Native Americans.

"While space is full of radiation, the earth's magnetic field generally protects the planet and people in low earth orbit from these particles."

The magnetic field protects only against charged particles (usually coming from the Sun). Galactic cosmic rays or solar flares are not blocked. The atmosphere blocks most of that, as well as the planet itself. In low-Earth orbit, you have half the horizon covered by the planet, so you get only half the radiation.

On Mars, you would get a little lower radiation as you would in low-Earth orbit. The atmosphere albeit thin does provide some shielding and the planet itself removes half the radiation (as in LEO). Greater distance from the Sun also reduces the impact of solar radiation.

Normal radiation levels pose little danger in space, you mainly have to worry about shielding during solar coronal mass ejections. When that happens, you usually have a few minutes to hours of warning (courtesy of our fleet of solar observing satellites). For adequate shielding you need to design a 'storm shelter' in the middle of the spacecraft, surrounded by the crew's food, water and waste.

Note that we've had astronauts spend years in space and the physiological damage was from low gravity rather than radiation. I don't understand why NASA has never built a rotating space habitat to solve this problem.

  I don't understand why NASA has never built a rotating space habitat to solve this problem.
Because it's difficult to do right. There is a maximum usable RPM beyond which humans cannot function due to dizziness/disorientation, and a somewhat lower max beyond which excessive coriolis effects would make working in the habitat incredibly annoying; generally, you don't want to go about 2rpm, though you could push it by screening your astronauts for spin-adaptability. This puts a lower limit on how large the habitat must be to achieve any particular level of spin gravity; for anything approaching 1g, it's pretty large, and no one knows just how little gravity is required to prevent the physiological effects of microgravity. To get even half a g at 2rpm, you'd need a structure 112 meters in radius, which is pretty dang big for a spacecraft.

You could probably still manage that with current technology if you just have two small spacecraft modules at the ends of a 224m tether (or a somewhat shorter tether if you have some unmanned equipment that's heavier than the crew module and can serve as a counterbalance rotating with a smaller radius), but then you've got a bunch of other problems to deal with. How do you dock with a rotating structure? Safely approaching a rapidly spinning tether in orbit is not an easy task. Then you have to match rotation, unless there's a non-rotating hub, which would result in enormous complications to the structure. How do you move it / do stationkeeping? All thruster burns now have to account for the structure's angular momentum. And stationkeeping will be more of an issue that with 'normal' spacecraft because tidal effects will make a tether in orbit want to wobble. Additionally, there may be electromagnetic drag to deal with, and the associated voltage buildup across the structure that you'll need to find a way to safely discharge.

And then there's space debris. If the cable is damaged, you either get flung off into an unrecoverable orbit, or you hit the atmosphere and burn up.

So, all in all, hardly surprising that NASA hasn't bothered yet.

How about a giant donut balloon that inflates once in space? NASA could fill it with balls and charge admission while waiting for the expedition's supplies to reach Mars.

An inflatable torus might be a good way to create a friendly working environment for further construction, but further construction will be required. There're still the issue of docking to worry about, and you get new problems when you allow inhabitants to move around an arc; some active system is required to ensure that, as people and equipment move about, other stuff gets adjusted to ensure that the center of rotation always remains at the center of the torus. Otherwise, it will start to wobble, resulting in different gravity levels around the torus and inducing stretching force along some axis. If the balance is successfully restored (and the station does not tear itself apart) but not quickly enough, then you have vibration damping issues to worry about.

These problems become less severe as you make the structure large and larger (and thus the mass of the inhabitants less significant), but larger structures are of course more difficult and more expensive to construct.

Why no 2001-style rotating orbital station? Probably because it's not easy, it'll be big and heavy, and Big and Heavy and Orbital is definitely not cheap.

Moving mass — people moving around — within a rotating structure will transmit vibrations throughout the structure, even with mass dampening.

As an example of the considerations around vibrations within ISS, astronaut Sunita Williams indicated that the ISS exercise equipment is intentionally isolated from the ISS structure, as the vibrations of the crew members exercising causes problems for the solar arrays.

Source: http://www.youtube.com/watch?v=doN4t5NKW-k

How a rotating space would help the problems with lack of gravity? I mean, our gravity is up-down and the acceleration from a rotating environment would be lateral. Doesn't that make difference to our body?

No, it doesn't. "Down" is defined by the direction of acceleration, so saying that the centripetal gravity would be somehow sideways doesn't make sense; your body has no means of telling the difference.

What your body can sense is the presence of coriolis effects.

Ok, let me rewrite.

The acceleration I feel is in the head-feet direction, so it's relevant for the muscles, since their fibers seems to be aligned in this direction. The centripetal acceleration would be perpendicular to the usual muscular development, so... in this scenario, would that place still work for astronaut's body?

No, it wouldn't. There is no meaningful way for gravity to be "perpendicular to the usual muscular development". You would orient your head-foot axis to match the direction of the acceleration you feel. Floors and walls in a space habitat would be built in that orientation. Doing otherwise would be just as stupid as lying horizontally on Earth and then complaining that gravity goes the wrong way.

Oh, I see. So it was more of a question that I could not observe how this would be built than its effectiveness per se. Thanks for clarifying.

On a side note, they mention one equipment like that in this novel(a hell of a good scifi): The Martian, by Andy Weir. Available for free online, really funny.

Out of all the of astronauts who flew, only 8(Some sources say 11) have died of cancer. About the same number of cosmonauts have died of cancer. Even fewer died of brain cancer. Deke Slayton was the only Skylab astronaut to die of a brain tumor.

Doesn't seem too surprising. The atmosphere and magnetic poles do work pretty hard to insulate us.

Precision medicine will work to prevent the effects of cosmic radiation and DNA sequencing will probably be used to select candidate that are less likely to develop Alzheimer's or cancer in high risk environments. Surely it's been already figured out but the article doesn't mention it.

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