Plasma Thruster


Some of you probably have plans to build your own spaceships, we know we do. Well, the propulsion system can be a bit tricky, especially if you plan on using plasma drives. This breakdown and build of a simple plasma thruster should help you on your way. All you really need is some Argon, a large capacitor bank, and a custom nozzle. You’ve already got most of that right? As usual, be very careful. This is high voltage and very hot.

34 thoughts on “Plasma Thruster

  1. Very cool!

    Anyone remember seeing a high school science fair project that demonstrated ion propulsion using I think knitting needles in plastic tubes suspended from a thin wire connected to an automobile ignition coil? Apparently by pulsing the current into the coil one could get this ‘rocket’ to swing like a pendulum. I think I read this in an old encyclopedia my parents had.

    1. Dude I thought I was crazy but you showed up on Google so this encyclopedia exists. I remember exactly this. Some old like “World Science Fair” project thing. like late 70’s encyclopedias. Yes. I tried to build it with BB’s, pen tubes, and welding wire once but didn’t have any of the automotive pieces to make the power.

      1. I remember the exact same thing but I think I saw it in the late 60’s. I used a straight piece of copper wire filed to a point on one end with a soldered on bb at the other end. I’m pretty sure I rounded up the car battery and ignition coil but chickened out when I read the coil output was 3,000 volts or so.

        1. I did get this to work with the BBs ,welding wire and a car ignition coil and won the local science fair in 1976. I was 11. What was the name of the encyclopedia? was it “Scientific American” or “Popular Science?”

    2. I was just talking about this with a friend tonight back in the early 70s my father bought me this mind control rocket that hung from the ceiling no moving Parts ion propulsion all I remember was seeing would look like a nail inside of it he wouldn’t let me keep it up because it’s fun so fast it was worried it would take my eye out

  2. This is the same basic principle as a Jacob’s Ladder, right?

    Too bad it’s not particularly powerful. I’d have figured out a way to mount it in the trunk of a car for an extra boost of speed. :)

    It’d make an awesome cigarette lighter, though. :D

  3. This is both really cool, and no small achievement! If his measurements of 20-40 N of thrust are correct, then this thruster is achieving on the order of the same thrust as some experimental ion engines. Most ion thrusters are measured in terms of milliNewtons, not Newtons! :)

    That being said, he probably uses more power and much more propellant than those designs, but for a hack attempt, that’s fantastic! :) Well done!!

  4. This definitely works differently to an ion engine. It seems to be very similar to a jacob’s ladder, although I always thought they worked due to the hot gas rising rather than magnetic effects.

    Someone with a jacob’s ladder try it upside-down please!

    20-40 N sounded like bollocks, but then I read his current is 30-40 kA!

  5. This thing is amazing to see in person just with the sheer amount of power it expels in just a short amount of time. The EMF it releases when it fires also causes massive amounts of distortion on any electronic recording device attempting to get a shot of it. It was a very impressive piece of work.

  6. An upside down jacobs ladder will just arc across the spark gap until it melts. The heat from the plasma is what causes the spark to rise from what I’ve read and seen with my own jacobs ladder. Yes, I melted the hell out of one while not paying attention while it was in a non-vertical mode (it fell over…oops!). Killer hack tho!

  7. I saw the development of this thing from start until its current state. A video would be awesome except the discharge takes place in 6ms. That is MUCH less that one frame of standard video, so it would need a high speed camera. The further challenge to that would be convincing someone with a high speed camera to allow it so close to such a large EMP. And it actually IS much closer to a rail gun then a Jacobs ladder. The Lorenz forces of the current flowing through the ionized argon accelerates the argon generating the thrust.

  8. Some comments from guy who designed and built that beast:

    1) This thruster operated at about 14 Megawatts peak.

    2) As shown, this device is actually an arcjet thruster. The operation is similar to a chemical rocket where hot gases are expanded in a nozzle to get thrust – except here the gas is heated by an electric arc.

    3) In order for magnetoplasmadynamic effects to generate the bulk of the thrust, the device must be operated in a near vacuum. I couldn’t get a hold of a large vacuum chamber so I went with arcjet operation instead.

    4) Total thrust of 20-40 N is respectable, but not a good performance measure. You could probably get 20 N by throwing a few bowling balls. A much more useful measure is thrust per unit of propellant mass. This is know as the specific impulse (measured in seconds. Yes, seconds. That’s just how the math works out.) The space shuttle’s main engines operate at about 450s. Arcjets operate around 2-3,000s. MPD thrusters operate upwards of 30,000s. My thruster was probably somewhere around 2,000s, which puts it at the low range of an arcjet. Not too shabby. Results probably would have been much better with a proper nozzle.

  9. Thanks, Matt. That’s a sweet bit of kit there. I’ve got a megawatt stack I could try, but previous experiments found tungsten melting like butter on a hot griddle. How’d the nozzle hold out?

  10. So you need 14 MW for 40 N thrust- or 350 KW for 1 N. Hm… If we suppose you are using solar cells with 350 W/m2, and 1 m2 of cells is only 0.1 kg mass, you need 1000 m2 of cells to produce 1 N thrust, and weight of cells is 100 kg. Then your acceleration is a=F/m=0.01 m/s. Not bad at all for an electric thruster, and with solar cells, working time is unlimited. In ~1 day you would achieve 1 km/s speed, in 100 days 100 km/s. That’s excellent! Even with solar cells weighing 1000 kg, design is still very good and useful, for example for asteroid belt exploration.

  11. Hey! speaking of space engines, I’ve got a
    doosie. I thought this up when thinking about
    the plausibility of using the equivelant of
    the electrons spinning around an atom (at the
    speed of light) but if you could get the atoms
    to go foreward and around, you wouldn’t be limited
    by rocket engines. (E=mc2 just use another
    source of controlled energy to stimulate the
    atoms) I warn you that he who tries this WILL
    die and be atomically disentegrated (not to mention BECOMING A NUKE!!!). But, I was thinking
    about the ability to control the stimuli and
    accelerate to any speed, not limited by any other
    internal force (except gravity and friction)
    but hey, what happens in space stays in space.

  12. * Using the electrons spinning around an atom
    for a method of invincible shielding (I was
    thinking that if everybody got those, people
    would get tired of shooting at each other
    and I would get the nobel piece prize for
    world piece) — Started saying that, but I
    accidentally skipped ahead (I was thinking
    about the lightspeed thingie) And, guess what
    (this is kick-ass, because nobody my age would
    probably have these ideas) I am 17.)

  13. @Phive

    That would be amazing if you didn’t use words like thingie…

    And if it wasn’t complete BS.

    Prove me wrong, anyone can say ‘I was thinking about using a microwave oven to make plasma particles to use in my superluminal propulsion system’

    1. It is so much easier to prove a person wrong in theory than it is to prove them correct in theory. In the Canary Islands in the late 1950’s until the early 1960’s the US Navy began to research microwave particles as a viable energy source. This research was due to the fact that a group of radar outpost operators set fire to the sea by inadvertently directing the microwave emitting radar dish at the sea and just like when a fork sparks when placed in the microwave oven the metal salts in the sea minerals sparked enough to ignite HYDROGEN released by streaming microwave particles. Do not take my word for it. Google Hydrogen Sea fires. Not that I agree with Phive’s Physics or even the spelling of his Peace prize any more than I agree with you or anyone else believing that mistakes demonstrate low intellect. I in turn believe mistakes reveal only that we are human.

  14. Matthew,
    Have you gotten a chance to test this out in a vacuum chamber yet?
    If you were operating the device as an MPD as opposed to an arcjet, will there be a decrease in total thrust in exchange for greater specific impulse? (as I understand it, MPD operation requires low injected propellant pressures as well as near-vacuum operation)
    Lastly, how much Isp/thrust variability wiggle room do you have to match mission constraints along the lines of the VASIMIR concept, within reasonable limits of electrode lifetime?
    Cool build, hope to pursue something similar for my senior design.

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