34 thoughts on “Fusion Propulsion”

  1. Over/under on them destroying their testing facility, from the description of the process they plan on using? I mean, they have to have one hell of a protocol in place if they’re going to set off a directed fusion reaction of the described magnitude, right?

  2. Sadly, not much fact in the article, because it sure is interesting. From what I can read into it, looks difficult. Surrounding a droplet of Deuterium inside of a plasma chamber and then condensing a metallic body around it, followed by a compression to the point of igniting a fusion event, and then expel it out a nozzle for thrust.

    The article misleads a little bit, as it kind of leaves out what phase the “D” and “Al” are in when the collapse occurs. It does say they introduce a “drop”, i.e liquid phase, but goes on to say they have heated the “D” to fusion type temperatures in the magnetic field. This means it is now a plasma, and is no longer a “drop”. As far as the aluminum goes, same thing. Are they surrounding the drop of “D” with aluminum in the solid phase? I’m thinking timed sequences of rings that when put together, would become a spherical assembly. Now you push the magnetic field into a pinch and smash the hell of it.

    The idea looks like a fusion boosted electromagnetic pinch device.

    http://books.google.com/books/about/The_Electromagnetic_Pinch_Effect_for_Spa.html?id=n6xiNwAACAAJ

    The physics of the creating the pinch, and expelling already have a lot of previous theoretical and practical work done. However encapsulating a deuterium droplet with a metal and imploding sounds real simple, but throw in that this is probably/maybe? ( article doesn’t say) done at millions of degrees, and may involve phase transitions of the various elements at different plasma temperatures.

    Starting with normal matter as we experience it ( liquids/solids) and boosting it to a plasma via fusion energy is all I can conceive of.

    On the energy management side, it should be attractive, as it is a pulsed process, so any source of power will work, duty cycle being the output. The system seems like it just needs to maintain a strong enough magnetic field for performing the encapsulation of the Deuterium, followed by the pinch. The energy input to heat up the plasma is provided by the fusion event. Current plasma confinement fusion devices put a crapload of energy into just getting the plasma up to temperature and keeping confinement. This path looks to avoid that energy expense.

    I cross my fingers for them, but won’t hold my breath.

  3. Better information is available at their website.

    http://msnwllc.com/fusion-technologies

    Looks like the deuterium & metal are separate plasmas at the start of the cycle, and the plasmas then are smashed together. Not much risk of destroying the lab though, as the test are expected to produce no more than 5 joules of energy.

    Depending on how they miniaturize the equipment & scale up the reaction, it could be the basis for a nice 4th generation nuclear weapon.

  4. Scale it up and point it at a Bad Guy instead of at open space and you’d have something like a blaster from classic science fiction.

  6. The obvious question for anyone who says they know how to build a fusion drive is, “So why isn’t step one of your plan to build a fusion powerplant, providing cheap, clean, abundant energy to the world and making ten gazillion dollars to fund steps two through N of your plan?”

    I have yet to hear a good answer. Mostly, fusion rockets are snake oil that have worn out their welcome in the clean-energy community and are being peddled to the rocketry community on the grounds that we are usually a bit behind the curve on recognizing the latest fusion scams.

    1. Earthbound fusion power must indeed be price competitive with other technologies. The economics of space generated power are accepting of a tad higher price point per kilowatt-hour. It took a couple of $1B shuttle launches to install the 100kw (?) capacity of the ISS arrays. What would the per kwh price if power on the ISS work out to be through 2020? My point is that a space based fusion device (or fission) has economics that allow for a higher price point if it can just deliver the promised power. A non-starter idea for earth may be a-ok for space. If a lightweight 1MW space rated fission source was available, how much would value would it bring to schemes to travel to mars? It may only cost a few tens of millions to make, but you could sell it for perhaps billions.

      However, your warnings of fusion snake oil salesman would be wise for the rocketry community to heed. Fusion power exits solely in the realm of broken dreams and promises for now.

    2. Do you do the same thing when people say they’ve built a particle accelerator? Those can be used to make power plants too.. no-one does because it’s not competitive.

      1. Particle accelerators do not produce power, they consume it. They ultimately turn electric power into heat, which is exactly the opposite of what a power plant is supposed to do.

        Rockets, turn fuel and oxidizer into heat and heat into useful work. That is exactly what a powerplant is supposed to do, except that the work is in the form of thrust rather than current. Since we know how to convert thrust power into electric power, or vice versa, at 50+% thermodynamic efficiency, that’s not a big difference.

        A fusion rocket that can do with deuterium what a rocket does with LOX and kerosene, is also a generator, or close enough as makes no difference. A fusion rocket that can’t do that, is just another sort of plasma thruster. We’ve already got plenty of perfectly good plasma thrusters. What we don’t have, in the let’s-fly-a-rocket-to-Mars-in-a-month department, is a power source to drive them.

        I’m going to go out on a limb and say these guys don’t have one either, and aren’t going to build one. If they did, they’d be talking to all the people here on Earth who will pay real money (which is way bigger than space-program money) for a high-density power source with negligible fuel consumption.

          2. Trent, you obviously don’t know who John is or you would not have made such a silly statement… maybe you should take you own advice?

    3. “So why isn’t step one of your plan to build a fusion powerplant, providing cheap, clean, abundant energy to the world and making ten gazillion dollars to fund steps two through N of your plan?”

      Economics is certainly one answer, as Stan has said. I would also think that a fusion rocket technology would be easier because it would be easier to generate thrust than to generate power.

    4. The next most obvious question is, “So why isn’t step one of your plan for solar system domination to build a fusion thruster to double the maximum payload an airplane can carry because it won’t have to carry jet fuel?”

  7. That’s MR. Fusion to you Rand! BWAHAHAHAHAHAHAHAHA!!!

    It’s almost 2015. I want my Mr. Fusion and Flying DeLorean!

  8. “If a rocket ship could do that often enough — say, at least once a minute — Slough says you could send a human mission to Mars in one to three months, rather than the eight months it took to send NASA’s Curiosity rover.”

    We send humans to Mars with chemical rockets in one to three months.
    You just need a lot of rocket fuel.

    If want to send humans to Mars, you should support exploring the Moon
    to find minable water.
    With minable lunar water you get as consequent a lot of rocket fuel.
    So having lunar water mining means having access to Mars for humans.

    For near term human trips to Mars, you can simply buy a lot of rocket fuel
    for a high price, and have that rocket fuel shipped from Earth.

    But if a lot of rocket fuel is bought for use in space environment, one will cause their to be a market for rocket fuel in space, and which means one has a market for rocket fuel made in space.

    The question is not where to get the first 1000 tons of rocket fuel. The question is where do get the first 10,000 tons of rocket fuel and how much will the next 10,000 tons rocket fuel cost?

    So at $10,000 per lb or 20 million per ton. 1000 tons is 20 billion dollars.
    So, one can say getting the first crew to Mars safely is worth a lot of money. And getting the second crew to Mars is worth less money.
    And the tenth crew to Mars will worth very little.
    So spending extra 20 billion on first crew isn’t as much a problem as spending extra 10 billion the crews coming after the first crew.
    Or Congress has come close to spending 20 billion on SLS which isn’t going anywhere- which only now seemingly becoming a problem.

    You can politically afford to spend more on first trip, and if lower cost significantly on next trip this can be a selling feature.

    So for first trip to Mars, buy fuel shipped from Earth and by the second trip maybe you buy lunar rocket fuel. But by the third trips to Mars, it’s pretty certain you will be buying lunar rocket fuel.

    So using chemical rocket fuel, you try to get to Mars as quickly as one can afford to do it. So, maybe 3 months trip time. And maybe by third trip
    you going there faster, using more rocket fuel and buying the additional
    amount rocket fuel for same cost- getting more rocket fuel for same price.

    Whether you try to get there in one month time, is not particularly important but it could be done if one has the budget. With reduced budget, one may forced to take 3 to 4 month trip times. But over the years of going to Mars the rocket fuel cost per ton should steadily reduce in costs. And a century later, it’s fairly possible one is still using chemical rocket fuel to get to Mars.

    If you don’t want some kind of totalitarian regime involved with Mars settlement, it seems chemical rocket fuel is best.

    1. I never worry too much about what researchers say their research might be used for… they almost always have no clue.

      A working fusion rocket stage could help you go anywhere, not just Mars.

    2. gbaikie, OR…

      Instead of $20 billion for a 3 month trip, you pay $1b for a six month trip and offer the crew a few million each for their inconvenience and higher risk. Gotta love that rocket equation which works in both ways.

      I just had to state the obvious. Thank you gbaikie for bringing the subject up.

      Is mars worth a few billion investment? Obviously not. Mars is worth zero dollars today (but asteroids are worth trillions. Got it.)

      Those phony $20 deeds you can buy today aren’t actually tied to any spot on mars. but if they were?… (Say because of actual possession?)

      $20 per sq. km. is $2,880,000,000
      $20 per hectare is $288 billion
      $20 per half acre is 144 trillion

      A half acre is a typical home sized plot outside the density of a city.

      This is not only feasible but makes economic sense as well unless lower costs are going to happen almost immediately. Of course, it makes more sense as costs come down regardless of how long that takes. Costs will come down.

      Why would anyone pay more to be first? I could not say, but they do, don’t they? The first area developed will likely prosper first. Palm Springs, for example, is worth a lot, but surrounded by worthless desert. In my life I’ve seen many towns start out as not much of anything, but become amazing thriving and growing towns in as little as a decade. This is very difficult to visualize for some. Population centers attract people.

  11. The article implies that they have gotten a D-D reaction to work, and that substituting lithium for aluminum in the “ring” would increase efficiency. That would be by converting Li into tritium, and the D-T reaction has a much higher cross-section. In fact, it’s so much higher that it’s the only reaction path we’ve ever been able to make work in a bomb. D-D doesn’t work even in the belt-and-suspenders Teller-Ulam device. If they have actually gotten a D-D reaction to yield significant energy (even if far short of breakeven), that is the big news in this article.

    Also, I tire of people thinking that VASIMR is in any way comparable to this. VASIMR is just an engine that has to be supplied with external power, and leaves the little problem of providing that power (the biggest problem in propulsion) unsolved. VASIMR isn’t anywhere near as highly developed as the xenon ion engines that power the DAWN spacecraft, which is already tooling around the solar system.

    An engine using fusion energy deposited directly in the exhaust would almost certainly be easier to build than a power plant based on such an engine. By the same token, if someone could find a chemical reaction that would power a battery (not a fuel cell) with the same energy density as gasoline, the first application would be to rocket propulsion and not batteries for cars.

    1. Can the lithium metal ring do double duty as both hohlraum and fuel source? I don’t know if low z elements are desirable here, however since opacity/ X-ray absorption induced heating is not the source of the compression force, Maybe it doesn’t matter?

    2. I assume that by “gotten a D-D reaction to work”, they mean simply that they have caused some measurable number of deuterium atoms to fuse. That’s not big news. A clever high school student with a Farnsworth fusor can do that, and detect the neutrons to prove it. Several high school students have actually done this.

      Getting a D-D reaction to produce more energy than you put into the magnets, etc, would be a genuinely impressive thing. The article very carefully states that their scheme should produce a net energy gain, not that it has done so. And that’s a claim we have heard many, many times before.

      As for, “An engine using fusion energy deposited directly in the exhaust would almost certainly be easier to build than a power plant”, that is possible but far from certain. Even so, the market for the power plant is many orders of magnitude greater than the market for the rocket, so I’m thinking anyone smart enough to actually build such a gadget, is smart enough to add the extra power conversion hardware and market it to customers with real money.

      1. Their pursuit of it for propulsion instead of power may be as simple as which grant they could get at the time. If NASA wants to kick in some bucks for propulsion research and the DOE is still footdragging, then a propulsion system it is!

      2. But they are using lithium I thought as the metal that is compressed by the magnetic field. Surely that is so that neutrons produced by the D-D would convert some of the lithium to Tritium that would itself readily fuse under the conditions created?

        1. That was me, yes. And “snowball’s chance in hell” is about right for a working warp drive any time this century.

          Given the potential payoff, that’s probably worth some research funding, preferably accompanied by skepticism rather than hype. A more likely outcome, though still a long shot, would be a result that experimentally verifies the basic possibility of a “warp drive” but with engineering requirements far beyond our presently forseeable capabilities.

  12. I would have thought one problem with this entire idea is that much of the energy in the D/D fusion reaction comes out as energetic neutrons, and probably isotropically at that. This is bound to introduce some energy inefficiency.

    1. Yes but your dealing with fusion, parts per thousand of E=MC2, most of the lithium probably doesn’t neutron capture to Tritium that subsequently fuses itself producing more neutrons, probably only a fraction. That got to be the reason they picked Lithium as the blanket/compressor, can’t believe it is a coincidence. But still compared to chemical fuels that convert parts per billion that could still be very energetic. 200X the imput energy is huge. This particular fusion design probably isn’t very efficient, but a rocket needs a high power/weight ratio, that’s the most important thing.

    2. That’s the reason for the metallic outer layer, which should absorb a lot of the energy of the neutrons (in the nanoseconds when the whole thing is super compressed and the fusion reactions are running) and translate the neutron energy into thermal energy of ions that can be controlled by the magnetic nozzle.

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