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Moon Space

Moon Swirls May Inspire Revolution In the Science of Deflector Shields 76

Posted by timothy from the tractor-beams-still-a-challenge dept.
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.'
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Moon Swirls May Inspire Revolution In the Science of Deflector Shields More

Moon Swirls May Inspire Revolution In the Science of Deflector Shields

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  • Other uses. (Score:4, Funny)

    by Anonymous Coward on Tuesday June 10, 2014 @12:11PM (#47203687)
    When not in use, could the power from the deflector array be diverted to the weapons systems?
    • Yeah my first question was whether or not it would be strong enough to repel the Romulan's attacks.

      • Re:Other uses. (Score:5, Funny)

        by NoNonAlphaCharsHere ( 2201864 ) on Tuesday June 10, 2014 @12:21PM (#47203769)
        More importantly, can we reconfigure it to emit a tachyon pulse?
        • To many problems with temporal fluxes, can't be done

        • More importantly, can we reconfigure it to emit a tachyon pulse?

          Probably not, but I'd lay odds we could manage to get a coherent graviton beam out of it.

          20KW? Sounds to me like the Elephant In The Room is a small on-board nuclear reactor to power the craft.

      • Yeah my first question was whether or not it would be strong enough to repel the Romulan's attacks.

        Look. Polarizing the hull plating was good enough for grandad. It's good enoug

    • Sure, just make sure to use torpedoes instead of phasers if entering a wormhole when there's an engine imbalance

    • Re: (Score:1)

      by Rashdot ( 845549 )

      Or how about the holodeck.

  • Weak magnetic fields on the moon. (Score:1)

    by Anonymous Coward

    Isn't anyone curious what exactly is generating the magnetic fields on the moon?

    • Re: (Score:2, Funny)

      by Anonymous Coward

      I bet ICP would like to know...

    • Yeah, especially that big magnetic anomaly in Tycho crater.

    • Re:Weak magnetic fields on the moon. (Score:5, Interesting)

      by i kan reed ( 749298 ) on Tuesday June 10, 2014 @12:39PM (#47203917) Homepage Journal

      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.

      • Re: (Score:3, Interesting)

        by DoctorStarks ( 736111 )
        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 [wiley.com] 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.

    • most of it is believed to be left over from the early time when Moon still had molten core and a dynamo similar to what the Earth still has.

    • Little purple men.

  • Reminds me of how servo tabs work (Score:3)

    by Solandri ( 704621 ) on Tuesday June 10, 2014 @01:24PM (#47204299)

    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. [...] 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.

    Back in the days when they couldn't outfit a plane with hydraulic actuators, they'd use a servo tab [wikipedia.org] 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).

  • Next up: We need a centrifuge in orbit! (Score:4, Interesting)

    by wisebabo ( 638845 ) on Tuesday June 10, 2014 @01:25PM (#47204311) Journal

    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).

    • Re: (Score:3)

      by slew ( 2918 )

      Perhaps if we can dump the Ruskies...

      Actually, when it comes to the ISS, the "ruskies" might decide to dump the US first (at least the Russians claim that, "The Russian segment can exist independently from the American one. The U.S. one cannot."). Apparently Russia has already "banned" the US from using their RD-180 engines which power the Atlas V rockets used to launch our military satellites as a consequence of this Ukraine tiff...

      Perhaps you are unaware of how much regression has occurred the US space program. You talk about the science o

    • In the long run, I think we will re-engineer humans for space.

    • I'm sure the Russians will take your suggestion under advisement. As it stands now, they're more likely to be building a next generation space station than the U.S. is. Look at recent analysis of the U.S. Space Program. Insufficient funding and no realistic goals, I believe was the short summary. If the U.S. manages to build a space station with a rotating hab, it will be a commercial venture, like Bigelow's proposed "hotel" in space.

    • Planetary surface colonization is only a romantic sci fi fantasy. It would be much much easier to construct and equip rotating space stations than to colonize planetary surfaces.

    • Re: (Score:2)

      by Xyrus ( 755017 )

      Well, not necessarily. If we can integrate gravity into the GUT, we may be able to create and manipulate gravitational fields like we do with electricity and magnetism. But that's also assuming that the mechanism for creating and controlling such fields isn't prohibitive which is a pretty big assumption.

    • If you made a huge cylinder centrifuge building with different floors, all spinning at the same angular velocity, called omega, then the centripetal or centrifugal acceleration is omega squared times radius, is greater at the outer, lower on the ladder layers than up towards the center, and you can go from floor to floor to see what you like, and the workout gym should be on the bottom floor, with the biggest gravity, while you could sleep in a suspended sleeping back in the center core room that's not even
      • sleeping bag, not sleeping back.. i must be getting sleepy
        • The real reason to have the floors spinning at the same angular velocity and dropping gravity as you go to the center, is the Coriolis force. It's a weird force to try to explain, you can get some idea of it when you watch a video of a guy spinning a bicycle wheel, then flipping the rotation axis, or when you're handling fast spinning heavy metal objects, they have "extra" inertia that manifests itself in weird ways. A previous poster on Slashdot mentioned that the smallest radius cylinder he calculated peo

    • Re: (Score:2)

      by Xtifr ( 1323 )

      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.

      Disagree. Large-scale habitats/SPS/O'Neill Colonies have always been the best option. No huge gravity wells to deal with, since rotation provides your G's, and, while they are extraordinarily expensive, they cost nothing compared to a full-scale terraforming effort, and can provide a shirt-sleeve environment in basically no time flat. The one remaining big knock on them was the issue of radiation shielding, and now, that may be solved.

  • ... but then again, they might not.

    Is this a weaker version of Betteridge's law?

  • "And who knows what other tricks ..."

  • The cited paper refers to http://www.minimagnetospheres.org/ [minimagnetospheres.org], which has some interesting detail on the concept.

  • Cosmic rays (Score:3)

    by buback ( 144189 ) on Tuesday June 10, 2014 @03:24PM (#47205551)

    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.

    • Cosmic rays hit you down here on Earth too, even if the atmosphere does block some. But your cells have a certain capacity for repair, including DNA repair, and only if you're drained, and drained faster than you can replenish, do you have permanent effects. And by the way they "are" talking about solar radiation, in the sense of Aurora Borealis, hitting you. Go watch some youtube on Aurora Borealis to see what they are talking about hitting you without a magnetic shield. Aurora borelais happens at the magn

  • Whiter means less radiation?? (Score:1)

    by Anonymous Coward

    Don't things on Earth left to bask in the sun's radiation turn white and lose pigmentation? Rather than gain it?

    • Not everything. My skin does exactly the opposite. There may be a specific process at work with the lunar regolite.

  • Just an aside about the statement ending " .... that, until recently, astronomers could not explain."

    There's a lot of stuff like that in science. There are even things that we don't know that we don't know about.

    That should give a person pause for thought the next time they hear some scientist or engineer speaking definitively about some proposed solution to disease, the economy, and especially climate change.

    The more grandiose and definitive the idea, the more likely it is vulnerable to what isn't yet kno

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