

Study shows space travel is harmful to the brain - iProject
http://phys.org/news/2012-12-houston-problem-space-brain.html

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jlgreco
> _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.

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ComputerGuru
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.

~~~
jlgreco
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.

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SoftwareMaven
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.

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

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iwwr
"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.

~~~
gliese1337

      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.

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mkr-hn
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.

~~~
gliese1337
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.

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neurotech1
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.

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

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Catalina
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.

