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Spacecraft May Surf Magnetic Fields

Posted by kdawson on from the radioactive-space-stocking dept.

Maggie McKee writes "Future spacecraft may surf the magnetic fields of Earth and other planets, taking previously unfeasible routes around the solar system, according to a proposal funded by NASA's Institute for Advanced Concepts. The electrically charged craft would not need rockets or propellant of any kind. To get charged up, the spacecraft could either fire a beam of charged particles into space or simply allow a radioactive isotope to emit charged particles. Because long, thin filaments have large surface areas for holding charge, the spacecraft might look like Einstein's head — with wiry filaments sticking out at all angles — or a weird space 'stocking.'"

5 of 98 comments (clear)

  1. Re:Last I Checked by headkase · · Score: 5, Informative

    The Sun's magnetospere is bigger than the orbit of Pluto if I remember correctly. And it doesn't have to be exclusive, you could use the magnetic "sock" for a stage of the journey and maybe propellents in another stage of the same voyage and then you short range teleport for the last 5000km ;). It's just another useful tool to employ from a mission planning perspective.

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    Shh.
  2. Fixed it for you by TheTopher · · Score: 2, Informative

    Mason Peck of Cornell University in Ithaca, New York, US, has received a grant to study the idea, which is based on the fact that magnetic fields exert forces on electrically charged objects with a velocity that is not parallel with the field lines.

    I'm guessing this system will work by having an orbit that travels over the magnetic poles, as the magnetic field lines are much closer there, and reversing the charge between poles so that it doesn't end up at the same altitude as it started. One problem, the further you get from Earth, the further apart the lines and therefore, less force. It seems as if it's going to take a very long time to get anything close to an escape velocity (if even possible). Who knows, it may even be more efficient to just shoot those charges out the back, aka ion drives.

  3. Re:Umm... capacitance of the ball made of filament by Alex+Belits · · Score: 3, Informative

    Corona in a gas is easy to produce because gas can be ionized by strong electric field along the spike or fiber, giving you a lot of charged particles to carry your discharge current. In vacuum you have nothing but those electrons that are already in metal -- you can emit them if you are negatively charged, and can't emit anything if you are positively charged (think of it as a giant diode tube). Even if you emit electrons, you have to move very fast so magnetic field will divert them away from you, and once you are sufficiently positively charged, emission will stop.

    Most likely at best this will produce a cloud of electrons following a positively charged spaceship, so forces that magnetic field applies to both will almost completely compensate each other. With radioactive source of charged particles (positively or negatively charged), or electron cannon you can produce more charge on the spacecraft, and probably it can be combined with ion engine that produces charged particles anyway.

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    Contrary to the popular belief, there indeed is no God.
  4. A few glitches in this idea: by Ancient_Hacker · · Score: 3, Informative
    A few glitches in this idea:

    • Building up and keeping a substantial charge may be difficult-- the solar wind will tend to get in the way.
    • "Steering" is a bit misleading. Assuming you can only shoot out electrons, you're limited to one polarity of charge, so you can only turn in one direction, normal to the magnetic field.
    • Most planets have a bit of inclination, so you're going to be turning into an angle to the ecliptic-- not very useful if you want to aim at another planet.
    • A sudden solar flare is likely to really mess up the charge, leading to unexpected twists and turns.

  5. electric solar wind sail by jovius · · Score: 3, Informative

    There exists another interesting invention around about the same principles. This one however uses solar wind, not magnetic fields, is steerable and able to work itself against the solar wind by adjusting the polarity and charge of the individual wires. They are apparently doing practical research on this right now. A short english description can be found at http://www.electric-sailing.fi/index.html