First test of exotic space thruster ends in explosion


In 2006, Mason Peck at Cornell University in Ithaca dreamt up with an entirely new way to control satellites orbiting planets that have a magnetic field. The idea is based on the Lorentz force: that a charged particle moving through a magnetic field experiences a force perpendicular to both its velocity and the field.

So the plan is to somehow ensure that the spacecraft becomes electrically charged as it moves through the planetary magnetic field which should then generate a force that can alter the orbit or orientation of the vehicle. The big advantage of so-called Lorentz actuated orbit control is that it requires no propellant. That’s a big deal since the amount of fuel a spacecraft can carry is the main factor that determines its lifespan. Propellant-free propulsion could significantly increase their operaitng lives.

Today, Peck along with William Gorman and James Brownridge at the State University of New York at Binghamton present the results of the first experimental trials of the idea. The work was funded by NASA but it has to be said: it doesn’t look entirely promising.

The team tested the ability of various objects to hold a charge in a vacuum while being bombarded with plasma, as would be the case in orbit. To generate the charge on the test object, they attached it to a sample of radioactive Americium-24, an alpha-particle emitter, and applied a voltage. The electric field carries away the positively charged alpha particles leaving the object highly charged.

I’ll let the team take up the tale:

Microscopic arcing was observed at voltages as low as -300 V. This arcing caused solder to explode off of the object.

Obviously, a proplusion system that explodes while it is in operation needs some more work.

The early pioneers of experimental propulsion systems such as Robert Goddard and Werner von Braun all had to cope with catastrophic failures, so Peck, Gorman and Brownridge are in good company. And as long as nobody gets hurt, a decent explosion livens up any experiment.

So stick with it fellas. Something tells me that if NASA funds the future development of this system, we’re going to be in for some fun.

Ref: Experimental Study of a Lorentz Actuated Orbit

37 Responses to “First test of exotic space thruster ends in explosion”

  1. Marcel Dejean says:

    “voltages as low as -300 V.”
    Negative voltage?

  2. Bob Abele says:

    obviously you are not in engineering.

    An engineer would have noted that the statment was that: “…arcing caused solder to explode…”.

    Hint: exploding solder does not equal exploding Lorentz thruster.

    Note for future: Words have meaning.

  3. Dave R says:

    Yes, -300V is possible. It’s a negatively charged potential of 300V relative to ground.

  4. chris says:

    satellites have limited lifespans because space radiation fries the electronics after 5-10 years….

  5. Heimlich says:

    Relative to the ground? But this thing will be flying so much higher. I believe people are just making this stuff up. Space cannot really be charged, since it’s in a vacuum. Everyone knows this. Come on!

  6. Peter says:

    What’s your source on this? I’m pretty sure that the limiting factor is how much fuel they can store.

  7. David says:

    “Obviously, a proplusion(sic) system that explodes while it is in operation needs some more work.”
    Don’t tell all the rocket scientists. Their job depends on an exploding propulsion system.

  8. Josh says:

    He meant relative to ground “neutral ground” or “common ground” not dirt ground. To give a very weird example if you were to take a set of jumper cables and place both black ends on a piece of metal(it does not have to be in the ground) that metal piece becomes “common ground”.

  9. JohnD says:

    Now I know why I don’t read the comments on articles like this. Anyone who doesn’t think we need to spend more money on education just has to read some of these posts.

  10. dgg says:

    Re: negative voltage– it’s a very common convention.

    As others have written, voltage is relative to a reference (often called “ground.”) In transformers, for instance, the center-tap is usually the ground, and the two coil ends swing positive and negative in respect to that reference…

    (Think of a sine wave, and the ground is the horiz line between the wave peaks and troughs…)

  11. BillyBob says:

    It’s obviously the global warming that caused it…..idiots…….

  12. George says:

    …They attached it to a sample of radioactive Americium-24, an alpha-particle emitter. – Ahem, that is Americium-241. it is a transuranic isotope, half-life of 432.2 years, up-bread from Pu-239

  13. Ernest Adams says:

    If I commit a capital crime and get the electric chair, I want to be zapped with negative voltage so I’ll be a lot more alive instead of a lot more dead.

  14. Negalator says:

    I bet Haliburton or Dick Cheney was involved in the explosion. Thinks like that don’t “just happen”

  15. Dude says:

    These comments are pretty !@#$%# up…

  16. si says:

    I am pretty sure they will be using AC for the electric chair. That means the voltage will swing from 120 to -120v

    They don’t use DC current, that is harmless… at least that is what I remember from the Tesla/Edison AC/DC debacle.

  17. Jon says:

    The charge of anything is the number of protons minus the number of electrons. A neutral object has equal numbers of both. It doesn’t matter if you’re talking about an atom or a satellite.

    Im surprised they arent using electromagnets to generate a magnetic field that interacts with the planetary magnetic field… I guess very high charges is easier to maintain than high currents but still it seems difficult to control the charge.

  18. jondrr says:

    DC harmless?!?! grab the positive terminal of a car battery and put your tongue on the negative terminal. see how harmless.

  19. Japhy says:

    do they have a website?

  20. Ralf says:

    Gawd. Can we please require at least a decent high school science education for anybody posting here?

    Voltage is defined a the difference of electric potential in an electric field. If you have a potential difference of 300V between A and B, it’ll be -300V between B and A (for DX anyways.) If you swap the red and black jumper cables and attach them backwards, neither car/battery will like it (don’t try this at home, it’ll damage both cars/batteries and may melt the cable.)

    This has *nothing* to do with where Ground or Earth is. That’s just a convention to simplify things so you don’t have to deal with differences all the time.

    And… Space is not a vacuum. It is filled with atoms, ions and electrons. Just the pressure is waaay lower than on earth.

  21. [...] The first test of a thruster using the Lorentz force for propulsion has ended in explody-ness. [...]

  22. Unregistered says:

    Thanks Spanky. You smugness has been noted. Also your poor grammatic construct.

  23. Schoschie says:

    I’m pretty sure “Heimlich” was joking (trolling?) when he made that comment about the ground.

    Also, DC current is not harmless in general. Depending on voltage, current and other factors (resistance of your skin, moisture etc.), both AC and DC can harm/kill you. Actually, being harmed or killed with DC current would be a lot more painful.

    There is something I don’t get about this invention (although it’s a very interesting idea no matter what). If the point is to save propellant, how much is really saved if you do need to provide a power source to charge the satellite?

  24. Rolken says:

    I assume that the power source they have in mind is the Sun, which lasts a bit longer than your average fuel tank. :)

  25. [...] su un motore spaziale usando la forza di lorentz senza propellente the physics arXiv blog

  26. Packard says:

    There is no such thing as DC current or AC current. That would be like calling it Direct current, current or Alternating current, current. I here it present that way so offten, even by engineers, that I just though I would bring it to your attention.

  27. God says:

    Lightning is DC and I think it can kill you.

  28. [...] NASA’s new “next generation” propulsion system goes bang. [...]

  29. Jared says:

    Not necessarily. Electronics get baked and age, but they’re generally in a Faraday cage (keeps out all but the hard stuff); the real lifetime limiter is stationkeeping fuel. Which is the point of looking into exotic prop (non-chem) solutions.

  30. Matt J. says:

    I don’t think the article _said_ anything about charging _space_. It said something about charging satellites and test-bodies.

    It also said something about plasma: at the altitudes these satellites orbit, they _do_ go through plasma; space is not a perfect vacuum, it is just a very _hard_ vacuum.

    For something that really does look like a perfect vacuum, you have to get beyond solar wind and interstellar dust, i.e. go into intergalactic space.

  31. Matt J. says:

    You are not God, and lightning is not DC! To be DC, the current flow has to be _sustained_. Lightning is closer to the AC current represented as a “step function” using a Laplace transform.

    But even that is only a rough approximation. During that brief time, it is NOT steady, even if the overwhelming majority of current flow is in one direction.

  32. Matt J. says:

    I am sure the reason they are not using electromagnets is related to the paradoxical principle stated in my favorite E&M text as “magnetic forces do no work”.

    After all, if you take a close look at Maxwell’s Equations, you see that the force is always perpendicular to the direction of motion, therefore the dot product is zero: no work done.

    In the satellite case, this means they could use magnetic forces to _spin_ the satellite, but not to raise and lower the height of its orbit. But if they use the force due to the _electric_ field, that _can_ do work.

    What? That doesn’t make it clear? Well, I _did_ warn that it is paradoxical;)

  33. Demena says:

    Satellites usually run on solar power. Hence fuel for maintaining position is the limitation.

  34. Slugger says:

    This article had merits. Most of the comments on the article are a joke.

  35. Ray says:

    By chris on May 23, 2008 | Reply

    satellites have limited lifespans because space radiation fries the electronics after 5-10 years….

    Oh really? Hubble has been in orbit since 1991.

  36. Jack says:

    That’s why we’re replacing it. lol

  37. Jon Simon says:

    This idea is poetic, with satellites floating on a magnetic field. It seems it would take a lot of power to do a useful amount of work, and there are difficulties in being charged significantly differently from your environment.