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Thread: Impatient? A Spacecraft Could Get to Titan in Only 2 Years Using a Direct Fusion Driv

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    Impatient? A Spacecraft Could Get to Titan in Only 2 Years Using a Direct Fusion Driv

    Fusion power is the technology that is thirty years away, and always will be – according to skeptics at least.* Despite its difficult transition into a reliable power source, the nuclear reactions that power the sun have a wide variety of uses in other fields.* The most obvious is in weapons, where hydrogen bombs are …
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  2. #2
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    Typical. “Fusion power is the technology that is thirty years away, and always will be – according to skeptics at least.”

    I’m not that skeptical. I think ITER, a D-T test reactor could be successful in a few decades, and with sufficient interest that could lead to a larger reactor that could power itself and provide useful excess power in another twenty. So call it 60 years for a very large but useful D-T reactor. (That’s a pretty optimistic estimate based on how long the ITER research is estimated to take - their numbers - and how quickly a larger power reactor could be built if ITER successfully resolves all issues.)

    “Though still under development, the engine itself utilizes many of the advantages of aneutronic fusion, most notably an extremely high power to weight ratio. The fuel for a DFD drive can vary slightly in mass and contains deuterium and a helium-3 isotope.”

    D-He3 is not aneutronic, due to the D-D side reactions, which produce neutrons. Also, some tritium is produced which means more neutrons in D-T side reactions. The best you can say is that a reactor using D-He3 might produce fewer neutrons than one using D-T as the primary fuel. Neutrons would be one cause of reactor damage, but the charged particles in the hot plasma would be another.

    Not mentioned is that D-He3 is an inherently harder reaction than D-T. Maybe we can manage D-T in a power reactor in 60 years, but I’m not so optimistic for D-He3. Anyway, a harder reaction probably means a larger, more massive reactor even if reactor damage wasn’t an issue.

    Also not mentioned, He3 isn’t cheap to make and is very rare in nature (leading to some heroic lunar and gas giant mining proposals). Obviously the engine is “in development” since a working model can’t be built yet. And it isn’t a tokamak, unlike ITER. Tokamak is be best understood magnetic confinement fusion reactor. All of that means I have no idea how long it might take to get something like this working, if ever. But given that 60 years for an easier D-T power reactor is based on everything going right and enough interest to push through rapid development and funding, I wouldn’t hold my breath.

    Honestly, I think it is pointless to work on fusion rocket paper designs today. Maybe somebody will come up with a new approach in the coming decades and then there could be something worth working on.

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  3. #3
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    Quote Originally Posted by Van Rijn View Post
    Typical. “Fusion power is the technology that is thirty years away, and always will be – according to skeptics at least.”

    I’m not that skeptical. I think ITER, a D-T test reactor could be successful in a few decades,
    Well the skeptics have been right for the last 60 or so years, as that's how long the general consensus had been that " Fusion power is only a decade or two away ".

  4. #4
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    Quote Originally Posted by ronin View Post
    Well the skeptics have been right for the last 60 or so years, as that's how long the general consensus had been that " Fusion power is only a decade or two away ".
    There actually has been real progress, even if slow, but mostly on tokamak and D-T fusion for power reactors. However, that doesn’t mean that can all be applied to a D-He3 power reactor/rocket with a much less researched reactor configuration.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

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