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. 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.
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 think that so long as no one attempts a mission to Mars before they're actually ready to do so, we'll be alright.
I hope people continue jumping.
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.
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.
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.
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.
What your body can sense is the presence of coriolis effects.
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?
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.