Science Nerd Post: Reactionless Drive

EM DriveI’ve been very intrigued by this supposed reactionless EM drive. When I first heard of it, I was very skeptical, since it violates every law of physics we think we know. Hell, I’m still skeptical. But the fact is that several teams have built one of these contraptions and have measured thrust being generated. Now in MIT Technology Review, we’re offered a theory by which this drive could legitimately be producing thrust. As much as I think there’s probably something else going on here, I really hope this is true. At the risk of people accusing me of being a Debbie Downer again, this late election season has convinced me the only long term hope for libertarian-minded people is getting the hell off this rock and leaving the world’s troubles behind. I’m becoming more convinced that free people need a frontier, because without one, eventually, the meddlers, swindlers, and sycophants of the world catch-up to us.

17 thoughts on “Science Nerd Post: Reactionless Drive”

  1. This kind of stuff is awesome because it represents a legit way to at least travel the solar system on manned missions. For probes you could get a look at other star systems.

      1. exactly. propellant mass fraction is a BIG limiting factor in space travel. for instance the space shuttle had a propellant mass that was nearly 80% of the total vehicle weight, just to get to low earth orbit. When you start talking about having to not only accelerate to your destination but decelerate when you get there, pretty soon your propellant mass is 95%+ of your total vehicle mass. It’s really easy to get into a death spiral of sorts where more fuel, requires more storage and structure, which again requires more fuel, on till it’s not a feasible design.

  2. I’d also like to point out that we first developed steam engines without really understanding the physics behind them. Thermodynamics as a field really got started with people trying to describe the workings of steam engines and improve their efficiency. It’s entirely possible we’re seeing something similar, where a new drive tech is proved empirically and then the science behind it developed.

  3. Interesting how the initial reaction [pun intended] was – who cares about the experimental data; the science is settled.

    It’s a good thing that work is being done on this in China and other countries. That prevents bureaucrats in this country from mucking up the works. [E.g., the EPA announces that the EM drive causes global warming…] Because a new frontier is dangerous to the bureaucrats and their little fiefdoms.

  4. As interesting as this drive is, there’s no way it’s getting is off this rock.

    The MIT Tech Review posits that it takes advantage of quantized momentum, which means that it’s thrust will always be minuscule, and any drive using the same principle will have the same problem. It may be a great way to send out probes. Humans? Not so much.

    While I agree that humans thrive in an environment that allows for expansion and leaving behind exhausted resources, it may be that those opportunities will be far harder to achieve than learning to live sustainably.

    (I believe this conundrum may be universal, and explain the Fermi Paradox…)

    1. Even a small amount of thrust, executed over a long period of time, can produce big velocities. Cutting the need for fuel mass, also cuts the overall mass of the vessel, thus requiring less thrust for a particular acceleration.

      I’m also not an expert on the quantum physics side of things, my background being engineering, but based on the article it seems like there’s already the possibility of manipulating the unrah wavelength. If that turns out to be true, then scaling up the thrust is a distinct possibility.

  5. Pardon me if I remain skeptical. It just seems like cold fusion all over to me. The effects noted in this case are so small that I think it’s quite likely they are due to measurement errors or something similar.

    As for not understanding the physics, we’ve got a pretty good handle on electromagnetic radiation and its effects at this point. It’s a mature science in a very real way that thermodynamics wasn’t when steam engines were invented.

    Maybe there really is something there, but I wouldn’t get my hopes up.

    1. I’ve been waiting for this to fall apart, but so far NASA, the Chinese Space Agency and a German team (at least) have replicated the effects. So the experiment does something reproducible. So far they have eliminated as many variables as possible – even fired it up in vacuum chambers. I guess it could still fall apart, but so far it looks like there is something there. Like the MIT theorist said, all his theory requires is for massless particles to actually have mass, and then they kinda have to break the speed of light inside the little contraption. So not much of a stretch…

      The thrust diminishes at higher velocity, but the fact you don’t have to carry fuel as mass – you could potentially reach low relativistic speeds (fractional but non-trivial) for spacecraft that leave from near-Earth orbit with some materials and emitter improvements. Again…all theory that nobody understands right now.

      Maybe Yuge Discovery. Maybe Yuge Eggface.

      Anything would beat strapping your ass to a bomb for a long-distance cruise. Forget speed – the idea of a controlled flight beyond earth-orbit (vice long glide paths) is pretty astounding. Probably worth the R&D.

      1. It is one of two current methods being researched. The second is based on the “Mach Effect.” This one (presumably) derives from quantum mechanics and the Mach Effect from General Relativity. All that is really known at this point is there are some odd thrusts (albeit small) that can be made without propellant. Research is still ongoing and hopefully will come to some interesting results and a theory or two as to why they work. The Chinese work, IMO, has some errors given their numbers are so wild compared to the others. The NASA work, however, is being done with a lot more rigor. The Mach work is also top-notch.

        So there is still hope of getting off this rock. Until then (and always) we have to stand our ground and make them fight for every smidgen of space and control. I hope it doesn’t come to a more physical form of fighting. Americans just need to get up and get moving in the political fights.

      2. You know what else is worth the R&D? Using nuclear explosions as propulsion. You can get, theoretically, speeds approaching 1/10th the speed of light. That means putting a probe in the vicinity of Proxima Centauri in less than 50 years, which is a reasonable life span to plan for.

        You can also shorten manned missions to, say, Mars from many months or several years to just weeks.

        Too bad the whole concept is prohibited by international treaty.

        1. Theoretically, yes. The bone-jarring accelerations might also reduce the joy of walking on Mars. A nuclear rocket is a much smoother approach, and achieves the same goals. Unfortunately we signed a short-sighted treaty that has prevented capitalization of the technology ever since. Its too bad as what we had in the 60’s addresses many of our space faring needs now.

        2. The problem with getting up to that high a percentage of light speed without some kind of deflector shield tech is that impacts with small space debris stop producing energy via Newtonian physics (Force = Mass * Acceleration) and start using Einsteinian physics (E = MCsquared). Which means that a 1 pound rock would vaporize the space ship.

  6. I’ve been on this earth long enough to know that the meddlers, swindlers, and sycophants of the world are us, and we are them. It doesn’t matter how far you go, all of those problems are alive and well in every man, woman, and child’s heart. Democrats love to otherize gun owners. Republicans have decided to otherize LGBTQ folks. Libertarians know all this, and they still have to battle their own urges. We are a hierarchical species of monkeys that lives on a plane of existence with limited resources. Those urges are baked in the cake.

    1. To a large degree that’s true. But I would note that it takes some time for them to organize themselves into systemic oppression. You might have a despot here or a despot there, but as long as you have the ability to move on, you can keep on moving.

  7. Assuming that this proves out the tiny thrust isn’t necessarily a killer. Sure, you can’t scale the system up to get more thrust, but there’s nothing stopping you from using arrays of hundreds of small thrusters to get a larger total thrust. And, of course, any thrust will add up over time.

    1. The irony here is that the “EmDrive” loses thrust as velocity increases. The inventor has a paper on it.

      But you have to figure that if this is really a new not-understood feature of physics, that we are just scratching the surface. There might be a whole lot more leeway once the theoretical principles are understood, or at least fleshed out. The first nuclear “reactor” was a pile of pellets managed by an axe with a tractor as a backup in case it started going critical, but not long after came Nautilus.

      I think it’d be nice if they discovered something new. Especially since the guy who did it was called a crank for the last 15 years or so. He’ll probably die as poor as most other inventors in his lot, but at least he might know he served up some crow before he checks out.

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