Electrodynamic Tether

(en.wikipedia.org)

83 points | by Amorymeltzer 846 days ago

2 comments

  • dr_dshiv 844 days ago
    I remember reading about this at the time. As a 15 year old obsessed with Nikola Tesla, I thought it was the coolest thing in the world. A 20km tether that generated electricity using the Earth’s magnetic field as a dynamo? Wow.

    “NASA has conducted several experiments with Plasma Motor Generator (PMG) tethers in space. An early experiment used a 500-meter conducting tether. In 1996, NASA conducted an experiment with a 20,000-meter conducting tether. When the tether was fully deployed during this test, the orbiting tether generated a potential of 3,500 volts. This conducting single-line tether was severed after five hours of deployment. It is believed that the failure was caused by an electric arc generated by the conductive tether's movement through the Earth's magnetic field.“

    • m4rtink 844 days ago
      You are trading IIRC height or speed for the energy you "pump" out of the electrodynamic tether. So it's not a pure power source, but you can use it to maneuver in Earth's magnetic field without using propelant, with energy from solar panels.

      Or possibly you can use it as a battery, "dragging" something up with solar power, then converting that potential energy back to electricity. :)

      • hinkley 844 days ago
        I can't recall if it was NASA or Tethers Unlimited that proposed using solar power to boost a tether into a higher orbit to offset some of the momentum transfer.

        Since we aren't spending a lot of time on these systems, I'm guessing they've discovered how impressively complicated it is to do a 4 dimensional rendezvous. It's hard enough in orbital mechanics to hit a 'stationary' object, and now you're going to spin it end over end...

  • halvor 844 days ago
    the superior way of accelerating/decelerating stuff in space. if you are fascinated by this mode of propulsion email me at halvor@solstorm.io. we are hiring
    • JPLeRouzic 844 days ago
      > the superior way of accelerating/decelerating stuff in space.

      I am a lay person but IMO you are confronted to some hard challenges:

      - Where do you attach your tether on the targeted satellite as each of the ten of thousands satellites in orbit is not built in a standardized way?

      - What is the risk that the targeted satellite desegregates when pulled down by the tether and debris stay in orbit for a long time? Particularly antennas and solar panels?

      - What is the risk that in the dragged down procedure, your satellite/tether combo endangered another satellite?

      - How do you plan to recognize the attachment point, and to maneuver around the satellite to reach it? For example the attachement point could be "buried" in an unreachable location because of antennas or solar panels?

      • halvor 833 days ago
        the answer to all your questions are simply to attach it on the satellite prior to launch.
      • tata71 843 days ago
        Why would he mention this stuff here?
        • JPLeRouzic 842 days ago
          As noted in other comments, electrodynamic tethers are used in space since a lot of time. What is interesting is how to solve practical challenges such as using a tether with a satellite target that was not designed for this kind of operation.

          In 2011 I attended the first 100YSS conference when it was organized by the DARPA (a big thanks DARPA!) and there was a very interesting presentation about these topics.

          https://en.wikipedia.org/wiki/100_Year_Starship#100_Year_Sta...