Deflector Shield to Maximum!

[Sparrowhawk]

http://space.newscientist.com/article.n ... news_rss20

Magnetic "deflector shields" could one day guard astronauts against dangerous space radiation, if experiments now underway pay off.

[Boothby]

Interesting article.

But it also mentions that UHMW (Ultra High Molecular Weight Polyethelyne) is also a good shielding material (great stuff, that UHMW!)

[jotabe]

Dunno what to say.
For one, we still don't know the effects on human being of such high magnetic fields.
For other, i have always been a fan of water shields: you have shield, fuel and beverage in a single fluid!

[Dr. Mobius]

There might be a little problem though if you hit a dust mote at 20k mph and your shield, fuel, and beverage spews out through the impact hole.

[jotabe]

At that temperature, water would freeze instantly, patching it ^_-

[eriador]

Huh? No... other way round, it would boil because of the pressure. Space isn't all that cold, because there aren't any molecules to rob kinetic energy from a substance.

In the case of a person, exposure to hard vacuum doesn't freeze you, but instead causes bruising (from capillaries bursting under pressure), and in longer exposures your fluids boil away, which causes all sorts of problems (like the bends, but worse). Hypoxia is also a problem because air gets sucked out of your lungs, but that's not what we're talking about.

[jotabe]

That's right, i didn't think it through. Vacuum of space would evaporate it rather quickly.

But eventually, i think it would freeze, since we are talking about large amounts of water. If the "water shield" was directly in contact with the casing of the ship, it would be already beyond frozen (giving enough time of travel in space).

About human beings... has it been ever done the experiment? Getting an animal without protection out to the space: what would happen first? Blood vessel embolia or freezing? Afaik, the experiments have been done in ultra-vaccum chambers on earth, so it couldn't be as cold (correction: low temperature) as the space.

[mazer]

Dunno what to say.
For one, we still don't know the effects on human being of such high magnetic fields.

don't we live in earth's magnetic field?

[eriador]

But eventually, i think it would freeze, since we are talking about large amounts of water. If the "water shield" was directly in contact with the casing of the ship, it would be already beyond frozen (giving enough time of travel in space).

Only if it were kept under pressure.... and then it would take a while.

About human beings... has it been ever done the experiment? Getting an animal without protection out to the space: what would happen first? Blood vessel embolia or freezing? Afaik, the experiments have been done in ultra-vaccum chambers on earth, so it couldn't be as cold (correction: low temperature) as the space.

Space isn't low temperature. There is nothing to BE cold. Remember, heat is simply random motion of molecules, so something that is colder has less random motion. In space, there are no molecules around to move, so it can't be cold.

Anyway... I've heard of some cases of people being exposed to hard vacuum (for example: in NASA test chambers). IIRC, they passed out from hypoxia pretty quickly, because the air got sucked out of their lungs. After that was the bruising caused by capillaries bursting. Also, dehydration (especially around mucus membranes) happens very quickly, as liquids boil away in the low pressure.

[Wil]

About human beings... has it been ever done the experiment? Getting an animal without protection out to the space: what would happen first? Blood vessel embolia or freezing? Afaik, the experiments have been done in ultra-vaccum chambers on earth, so it couldn't be as cold (correction: low temperature) as the space.

Space isn't low temperature. There is nothing to BE cold. Remember, heat is simply random motion of molecules, so something that is colder has less random motion. In space, there are no molecules around to move, so it can't be cold.

Anyway... I've heard of some cases of people being exposed to hard vacuum (for example: in NASA test chambers). IIRC, they passed out from hypoxia pretty quickly, because the air got sucked out of their lungs. After that was the bruising caused by capillaries bursting. Also, dehydration (especially around mucus membranes) happens very quickly, as liquids boil away in the low pressure.

It's CRAZY, but I was talking to someone about this just the other day. I eventually found this and all questions were answered!

http://imagine.gsfc.nasa.gov/docs/ask_a ... 70603.html

[jotabe]

Well, space is not really empty: the vacuum is never perfect. The small density of particles allows us to assign a temperature to the space.

But this discussion is reminding me more bits of data: in space we almost won't lose heat due to conduction. Our body is permanently radiating infra-red; this loss is negligible in the high density medium that is our atmosphere. In the space, though, the insulation against the losses due to radiation is the most important thing.

I don't know how long it would take, if longer or shorter than death due to depressurization, but we would end up frozen. Maybe not frozen as in "all your water turns into ice", since that would require exchange of heat with the particles in the space, but as in "cold enough to bring metabolism to a halt".

Now that i think about it, this loss of heat would happen even if we where in a particularly hot region of the space but with the same density.

For Mazer: Earth magnetic field is very weak, at least compared to the fields that would be required to shield a spaceship against charged particles.

[eriador]

Ehhh... Wil found the link describing what I was trying to say. But yeah... you have a point.