Update: Propellant-less Propulsion Piece Gains Traction Again…

Enterprise Picture…but still has nothing to push off from.

Doubtful News readers may remember the 2014 story of a research group that had built a device to create thrust without propellant. The 2014 experiment was taken to task for performing their experiments in a non-vacuum chamber, and this potential weakness was even noted in the conference paper on the experiments (paywalled).

Is NASA about to crack interstellar travel? (Atlanta Journal-Constitution):

One explanation other physicists came up with last year was that the air around the EmDrive must have been interfering with Eagleworks’ measurements, so this time they measured it in a vacuum. Guess what? It still seems to be working.

So we have a new paper? Well… not quite.

The source cited by news sources on this story is this forum discussion. The forum, at NASAspaceflight.com, is not affiliated with NASA, but this doesn’t stop some news sites, like Daily Times Gazette, from conflating the two:

NASA has, once again, successfully created a breakthrough in space travels with their new electromagnetic (EM) propulsion drive that could act as a “remote” which assists journeys within the solar system.

[…]In NASA’s official page (NASASpaceFlight.com), the drive will enable the transport of a spacecraft to the moon in just a couple of hours and a visit to the Red Planet – Mars, may take only 70 days.

Just so we’re clear, NASA’s official site is Nasa.gov, and is not affiliated with the research group, its claims, nor the discussion forum in question.

As we are often reminded concerning extraordinary claims, “science by press conference” (Wikipedia) isn’t really science. I can’t imagine “science by Internet forum” would fare much better.

The group’s proposed mechanism for propulsion involves interactions with virtual particles in vacuum space. I suspect it’s more likely along the functional lines of a radiometer (Wikipedia), which also functions under a partial vacuum, but I’d be happy to be wrong.

That all said, a working reaction-less propulsive drive would open new avenues in physics. It would change the world(s)! So what would convince skeptics? First, the Eagleworks group could submit their data once more for peer review. Once the results and (equally importantly) methodologies are published, it would be up to the scientific community to evaluate the idea and attempt to replicate it. Then we could move forward. And outward. And every which way, really.

See also:

  7 comments for “Update: Propellant-less Propulsion Piece Gains Traction Again…

  1. One Eyed Jack
    May 5, 2015 at 4:45 PM

    If such a drive actually worked, there would be no need to promote by internet forum. NASA and every commercial space program would be beating down doors to get access to it.

  2. Kevin
    May 6, 2015 at 3:05 PM

    Propulsion systems work due to conservation of momentum. If nothing (no mass) is being ejected, nothing will go forward. While solar sails don’t involve ejection, but instead on collisions of particles from the sun (or photons from the sun, whichever). I can’t imagine how moving virtual particles around could create propulsion – virtual particles have virtual mass (i.e. real mass). If they system worked in air, it would be by pushing air particles (i.e. air is the propellant).

    I call BS on this idea.

  3. Blargh
    May 6, 2015 at 4:39 PM

    If nothing (no mass) is being ejected, nothing will go forward.

    Nitpicky, but: you don’t actually need mass. Despite having no mass, photons still have momentum, which is how solar sails work (as… sort of… pointed out already :)). So you can produce thrust just by pointing an antenna, laser or similar backwards and radiating away (see for example the Pioneer anomaly – an anomalous acceleration of the Pioneer probes, which for years generated all sorts of interesting new physics hypotheses, until it was found that it simple uneven radiation of heat from the probes could explain it). IIRC, when I eventually did the math on the original story I found that the potential photon thrust was around the same order of magnitude as the reported thrust from the drive (though I’m still voting for ordinary convection).

    As for virtual particles and thrust, well… there is the Casimir effect.

  4. Kevin
    May 6, 2015 at 4:48 PM

    Yes, I realize photons have momentum. I guess I should have made that clear. It is also why solar sails could work. I suppose a solar panel could be used to reradiate photons back towards the sun –> basically an alternate version of a solar cell.

    As for the Casimir effect – I don’t know if that would be capable of generating propulsion. It only works because of tiny distance between the plates excluding some wavelengths of virtual particles from the gap, resulting in more virtual particles pushing against the plate on the outside than on the inside, or something like that. However, magnets also work by virtual photons, so maybe I have erred in my thinking, and maybe that is why you brought up the Casimir effect. Yes, virtual particles have real effects. Very real effects. They are also involved in Hawking radiation.

    I was wrong. Of course, that does not mean that the propellant less drive works.

  5. Artor
    May 9, 2015 at 12:31 AM

    Ultimately, it will be experimentation that means it will work or not. So far, the experiments seem to be having some successes, even if nobody knows why or how yet. It would be cool if we have to revise what we know of physics, but I agree it’s unlikely. It would be awesome to be able to get a probe to Alpha Centauri in our lifetime though.

  6. Kevin
    May 11, 2015 at 12:59 PM

    I agree that it is experimentation, and not theorization (especially not by me) that will ultimately validate or not this idea. It would be an interesting development if it does work, and if it turns out to have some practical utility. Also, I can think of nothing I would like more than to have a probe to another star in my lifetime.

  7. May 16, 2015 at 1:00 AM

    I’ve heard how the force this thing generates is in the same range as the possible error range of the measuring equipment, so there’s a good chance they weren’t measuring any force at all.

    But if someone with enough knowledge and money believes it works, they can predict the force generated by a substantially larger one, make it, and see if anything near such a force is generated. If so, their Nobel Prize winnings will be a drop in the bucket…

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