The Human Body May Not Be Cut Out For Space 267
Hugh Pickens DOT Com writes "The human body did not evolve to live in space, and the longest any human has been off Earth is 437 days. Some problems, like the brittling of bone, may have been overcome already. Others have been identified — for example, astronauts have trouble eating and sleeping enough — and NASA is working to understand and solve them. But Kenneth Chang reports in the NY Times that there are some health problems that still elude doctors more than 50 years after the first spaceflight. The biggest hurdle remains radiation. Without the protective cocoon of Earth's magnetic field and atmosphere, astronauts receive substantially higher doses of radiation, heightening the chances that they will die of cancer. Another problem identified just five years ago is that the eyeballs of at least some astronauts became somewhat squashed. 'It is now a recognized occupational hazard of spaceflight,' says Dr. Barratt. 'We uncovered something that has been right under our noses forever.' NASA officials often talk about the 'unknown unknowns,' the unforeseen problems that catch them by surprise. The eye issue caught them by surprise, and they are happy it did not happen in the middle of a mission to Mars. Another problem is the lack of gravity jumbles the body's neurovestibular system (PDF) that tells people which way is up. When returning to the pull of gravity, astronauts can become dizzy, something that Mark Kelly took note of as he piloted the space shuttle to a landing. 'If you tilt your head a little left or right, it feels like you're going end over end.' Beyond the body, there is also the mind. The first six months of Scott Kelly's one-year mission are expected to be no different from his first trip to the space station. Dr. Gary E. Beven, a NASA psychiatrist, says he is interested in whether anything changes in the next six months. 'We're going to be looking for any significant changes in mood, in sleep, in irritability, in cognition.' In a Russian experiment in 2010 and 2011, six men agreed to be sealed up in a mock spaceship simulating a 17-month Mars mission. Four of the six developed disorders, and the crew became less active as the experiment progressed. 'I think that's just an example of what could potentially happen during a Mars mission, but with much greater consequence,' says Dr. Beven. 'Those subtle changes in group cohesion could cause major problems.'"
Re:Roll on! (Score:5, Informative)
Dealing the coriolis and tidal forces might be worse than the problem it's trying to solve, unless you have a really enormous centrifuge.
Re:That's some bad eyeball squashing (Score:4, Informative)
To be fair, in zero gravity, it's easy to get confused about 'under' and 'over'.
that's why I usually bet on the spread
A tethered design more realistic in near term (Score:4, Informative)
Turning one's head rapidly in such an environment causes a "tilt" to be sensed as one's inner ears move at different rotational rates. Centrifuge studies show that people get motion-sick in habitats with a rotational radius of less than 100 metres, or with a rotation rate above 3 rotations per minute. However, the same studies and statistical inference indicate that almost all people should be able to live comfortably in habitats with a rotational radius larger than 500 meters and below 1 RPM.
That would mean a rather massive structure. So, an alternative design that would use less material is two stations tethered together and rotating around a common center. Or a station and a counterweight. Still, this requires a strong tether, which also means additional mass.
This approach is suggested, for example, in this Mars Society article: The Use of SpaceX Hardware to Accomplish Near-Term Human Mars Mission [marssociety.org].
For radiation shielding, they suggest to use the "consumables", which probably means fuel, raw materials, equipment and water.
Re:Space or Lack of Gravity? (Score:5, Informative)
The Human Body May Not be Cut Out For The Ocean (Score:4, Informative)
PersonFrom1420 submitted via church door nail, "The human body was not designed by God Almighty to live on the ocean in seafaring ships, and the longest any human has traveled has been close to coastlines. Without the protective cocoon of the coastal fish and shore leave, nautical travelers are subjected to Gout, Scurvy, and a malaise of the spirit that shall certainly result in dire consequence for any vessel attempting to find a new world to explore. In a Royal experiment, debtor's prisons are filled with scum of the streets, sealed away, and their outcome is surely the same as a nautical traveler who looks forward to a new life and possible riches from fruitful exploration. Also, if even one ship has a mutiny, NASA (the Nautical Authority of the Spanish Armada) should instantly force all manned sea faring traffic to halt for over a year, as various Royal Agencies, none of whom understand how to tie a knot, let alone sail a ship, confer over the loss, and consider halting this foolishness to focus on more incense swinging for the plague and merkin production at home. Certainly there is no profit to be gained in these new lands that are worth losing entire ships of human beings over, and there can be no future lands there that will ever be suitable for our children's children. May this missive find you in good health, Signed P.F.1420"
Re:Roll on! (Score:5, Informative)
Rats can't puke.
http://www.ratbehavior.org/vom... [ratbehavior.org]