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Moon Swirls May Inspire Revolution In the Science of Deflector Shields
KentuckyFC (1144503) writes 'One curious feature on the Moon's surface are "lunar swirls", wisp-like regions that are whiter than surrounding areas and that, until recently, astronomers could not explain. But one team of physicists recently showed that these areas are protected by weak magnetic fields that deflect high energy particles from the Sun and so prevent the darkening effect this radiation has. The problem they had to solve was how a weak field could offer so much protection, when numerous studies of long duration spaceflight have shown that only very powerful fields can act like radiation shields. The team now says that these previous studies have failed to take into account an important factor: the low density plasma that exists in space. It turns out that this plasma is swept up by a weak magnetic field moving through space, creating a layer of higher density plasma. That's important because the separation of charge within this layer creates an electric field. And it is this field that deflects the high energy particles from the Sun. That explains the lunar swirls but it also suggests that the same effect could be exploited to protect astronauts on long duration missions to the moon, to nearby asteroids and beyond. This team has now produced the first study of such a shield and how it might work. Their shield would use superconducting coils to create a relatively weak field only when it is needed, during solar storms, for example. And it would create a plasma by pumping xenon into the vacuum around the vehicle, where it would be ionised by UV light. The entire device would weigh around 1.5 tonnes and use about 20 KW of power. That's probably more than mission planners could currently accommodate but it is significantly less than the science fiction-type power requirements of previous designs. And who knows what other tricks of plasma physics engineers might be able to exploit to refine this design. All of a sudden, long duration space flight looks a little more feasible.'
When not in use, could the power from the deflector array be diverted to the weapons systems?
I bet ICP would like to know...
Yeah, especially that big magnetic anomaly in Tycho crater.
Educated guess:
Iron deposits. When exposed to a moving charged particles, say, solar wind, iron very slowly begins to magnetize, as individual electron spins are pushed very gently into alignment with their neighbors. We exploit this much more vigorously in the purposeful creation of permanent magnets here on earth.
I can't even begin to imagine how impossibly long it must have taken to happen on the moon.
Or another theory: it's magneto's secret moon base.
Technically meteorites are the parts of metors that make it to the Earth's surface. So micro or macro, meteorites are not a problem for space vehicles.
Back in the days when they couldn't outfit a plane with hydraulic actuators, they'd use a servo tab instead. Without hydraulics, all the force to move a control surface had to come from the pilot, which became a problem when the larger control surfaces like the elevator required several hundred pounds of force to move it.
The servo tab was a small flap at the end of the control surface (usually the elevator). It would deflect the airflow at the tail end of the elevator, causing the elevator surface to move in the desired direction, causing the elevator to deflect air in the opposite direction of the servo tab, causing the plane to pitch. In effect, the pilot only has to move a small control surface; the effect of the wind on that small surface would move the larger control surface for him. The MD-80 is probably the most common aircraft people are familiar with which uses servo tabs (it uses minimal hydraulics).
That's great! (No really: I'm not being sarcastic, that gets rid of one of the two great barriers to deep space travel and living on all the planets not-as-large-as-the-earth).
The other BIG problem is: What level of gravity do humans need to THRIVE for long periods of time? (That is so that they do not suffer from bone density loss, cardio-muscular problems, etc.) Is it 1/6 gee (moon)? 1/3 gee (mars)? Or will humans need a full 1 gee to live and, eventually, safely REPRODUCE?
If the answer is humans need a full gee, then we might as well just resign ourselves to limiting our trips into the solar system to quick jaunts and robotic explorers. (While you *might* convince colonists to spend say an hour a day doing exercises to maintain their health, no way would you be able to make a fetus do them). We'll need to re-engineer humans before we can make a serious effort to colonize another world. (The only rocky planet with anything near our level of gravity is Venus and it is a hellhole). That's why the loss of the centrifuge planned for the ISS that would examine the effects of "partial gravity" (as opposed to the "micro-gravity" the ISS currently has or the regular gravity that we have) on biological systems was so disappointing. Literally it would have told us whether or not colonization of space was really feasible in the near future. (It probably wasn't going to be big enough to hold people but just seeing how partial gravity affected laboratory mice would go a long way to answering these questions).
Perhaps if we can dump the Ruskies, with the money saved with using Space-X's rockets we could build a decent centrifuge to make these (literally) VITAL studies. Maybe we don't even need to attach it to the ISS; just take two of Bigelow's(?) inflatable habs, add a cable and spin! (Just by changing the cable length you could alter the g-forces so no additional propulsion other than the initial thrusting would be required). But that's the deluxe model, you could just take the Dragon capsule and have a cable attached to its spent second stage and spin THAT (the center of gravity might not be in the "middle" but it should work fine). Keep it in orbit for a few generations of mice and dissect them when they return.
While we're at it, we should probably look into circadian rhythms... (but maybe mars, with it's 24-1/2 hour "day" is close enough).
Protecting from solar radiation is great, but i understand that the greater threat is cosmic rays. Solar radiation is somewhat easy to block, because you just put a light element shield, like hydrogen tanks, between the astronauts and the sun.
Cosmic rays are much harder to shield from because they are so high energy. They also come from everywhere, so require a omnidirectional shield.
Just wondering why would Mars lose its oxygen and hydrogen to solar wind if such a small magnetic field can provide such big deflections?
rajmohan_h@yahoo.com
It's not a bad theory, but the leading candidate relates to impact processes that leave what is called "remanent magnetization". The science is not settled. The abstract here gives you a feel for the kind of discussions taking place (but you probably have to pay to get to the article). Google will turn up more work along these lines, including tests in hypervelocity launcher facilities.