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LCD 'Engine' For Spacecraft Attitude Control

Posted by kdawson on from the little-more-to-the-left dept.

Bruce Perens writes "Japan's IKAROS satellite, which earlier performed the first successful demonstration of a solar sail, has broken more new ground. Liquid-crystal displays — yes, like in your video monitor — were fabricated into strips on the edges of the solar sail. By energizing some of the LCDs and changing the reflective characteristics of parts of the sail from specular to diffuse, JAXA scientists successfully generated attitude control torque in the sail, changing the spacecraft's orientation."

8 of 95 comments (clear)

  1. A Crookes Radiometer? by Mad-Bassist · · Score: 1, Interesting

    It's neat to see this phenomenon being used for a spacecraft.

    --
    "The only legitimate use of a computer is to play games." - Eugene Jarvis
  2. Next up... by peacefinder · · Score: 3, Interesting

    Downwind faster than the solar wind!

    --
    With reasonable men I will reason; with humane men I will plead; but to tyrants I will give no quarter. -- William Lloyd
  3. Useful for stationkeeping? by GreenTom · · Score: 2, Interesting

    Neat. Anyone have an order-of-magnitude idea if this could be used for stationkeeping on sats in Earth orbit or for attitude control in deep space missions? Just wondering if it produces enough torque to control a real spacecraft. IIRC, for most spacecraft fuel for attitude control is the limiting factor on mission duration, and I think in some cases (e.g., Kepler) it's the only expendable. Could a spacecraft using this technique have virtually unlimited life? If you're solar powered and don't burn fuel, what limits lifetime-- dust on the solar arrays? Battery degradation?

    1. Re:Useful for stationkeeping? by GreenTom · · Score: 2, Interesting

      Fair enough, and didn't mean to imply that IKAROS is not real. But, IKAROS is a technology demonstrator. As far as I can tell, the solar sail is the payload, and it's performance requirements are based around testing the solar sail. I was wondering about the amount of torque this kind of setup produces, and if this technology is a potential alternative to thrusters for bleeding the reaction wheels on future spacecraft.

    2. Re:Useful for stationkeeping? by mangu · · Score: 2, Interesting

      if this technology is a potential alternative to thrusters for bleeding the reaction wheels on future spacecraft.

      I suppose that the idea is to make momentum dumping unnecessary. If the torque is always perfectly zero there will be no momentum accumulating on the wheels.

    3. Re:Useful for stationkeeping? by Bruce+Perens · · Score: 4, Interesting

      It seems you don't get solar wind in a magnetosphere, so the two systems each work best where the other won't.

      --
      Bruce Perens.
  4. Holography by Bruce+Perens · · Score: 2, Interesting

    How about using computed holography driving embedded LCDs to make a light sail act as a sort of synthetic-aperture device? You could have multiple steerable beams, receive with multiple steerable reflections, etc.

    --
    Bruce Perens.
  5. Re:All the torque that's needed by mangu · · Score: 2, Interesting

    As I understood from the press release, the purpose of the test was to find a viable way to control the attitude of the sail itself. Being so thin, it would flutter and probably be ripped apart if handled roughly. An LCD is an interesting idea in this context, although I believe the LCD would be orders of magnitude thicker and heavier than the solar sail.

    As for the momentum needed, it would be very small, because the disturbing momentum itself is very small. Since all the perturbation comes from radiation pressure, it's no big deal to get the correction from radiation pressure as well.