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Scientists rediscover the advantages of nuclear power for moving probes through the solar system

Scientists appear to have once again discovered the advantages of nuclear powered thrusters for moving much heavier interplanetary missions more quickly and more efficiently to the farther reaches of the solar system.

A new paper published last month in the journal Acta Astronautica argues that a fusion-powered drive, capable of delivering propulsion while powering onboard electronics, could be a way to get more power and cargo to outer moons like Titan, and designed a scenario revealing what a DFD-powered [direct-fusion-drive] Titan mission would look like.

A 2021 study from an international research team revealed that a DFD could transport 2,220 lbs to Titan in 31 months. Right now, the Dragonfly mission [to Saturn’s moon Titan] weighs in at about 990 lbs. This new paper says that the Princeton Field-Reversed Configuration (PFRC) concept developed at Princeton Plasma Physics Laboratory is essential for powering the mission.

The irony of this story is that scientists and engineers knew these obvious facts and proposed many versions of nuclear-powered thrusters back in the 1960s. NASA even had a very successful project called NERVA in the last 1960s, with plans to begin using the technology by the 1980s.

All such research was canceled however in the 1970s, partly because of budget cutbacks but mostly because of the paranoia that began developing at that time against using nuclear power for anything. The idea of launching a rocket into space that carried a nuclear rocket engine was considered environmentally too risky.

Has that fear now subsided? We shall see. There are plenty of environmental activist groups that we can expect to immediately oppose such technology. The question will be whether a large enough private industry will evolve capable of exerting its own political weight to resist that opposition.

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  • Bob Wilson

    Unfortunately, the study you linked posits a nonexistent fusion drive. But the concepts developed in the 1960s based on fission reactors are definitely feasible right now. See this article.

    “a fission reactor can be used in a rocket design to create Nuclear Thermal Propulsion (NTP). In an NTP rocket, uranium or deuterium reactions are used to heat liquid hydrogen inside a reactor, turning it into ionized hydrogen gas (plasma), which is then channeled through a rocket nozzle to generate thrust.”

    “A second possible method, known as Nuclear Electric Propulsion (NEP), involves the same basic reactor converting its heat and energy into electrical energy which then powers an electrical engine. In both cases, the rocket relies on nuclear fission to generate propulsion rather than chemical propellants, which has been the mainstay of NASA and all other space agencies to date.”

  • Jerry Greenwood

    Am I missing something here? Key word here is Fusion. At the moment a Star Trek transporter would be a good candidate too.

  • Doubting Thomas

    Starship would be a great system to loft a NTP system into earth orbit for these type missions.

    Many advantages, not the least would be to driven the enviro nuts TOTALLY crazy.

  • Jeff Wright

    Starship doesn’t carry hydrogen–and won’t–and LH2 is the only good fuel for NTR—that means SLS

  • pzatchok

    Fusion power is the only viable option to get us to the stars on generational ships.

    Fission power engines suffer a LOT of drawbacks that can not easily be fixed in space.

    Fission powered electric engines are the best option for long term space use.

    Why are people so obsessed with getting inside our solar system faster? We are only going to send robotic probes to anyplace other than the Moon or Mars.
    I want to see a working fusion reactor in space.

  • Jay

    Hydrogen is not the only good fuel for an NTR. I always thought ammonia was the best fuel (Isp vs. storability), but after reading a comparative analysis from Bob Braeunig who compared the Isp vs. storability, along with other advantages and disadvantages of fuels, methane is the best all around fuel to use.
    Hydrogen NTR, 850-900, excellent Isp, poor storability & density, heavy.
    Methane NTR, 650-700, high Isp, fair storability & density, heavy.
    Ammonia NTR, 400-450, Medium Isp, good storability & density, heavy.

  • Mike Borgelt

    Starship could carry the NTR engine and tank into orbit and be refueled by tanker versions with methane or even hydrogen as I’m sure a tanker version carrying a hydrogen payload will be possible. SLS is an expensive dead end going nowhere in a hurry. Best if it just disappears.

  • Jerry Greenwood

    I’d like to see a working fusion reactor on earth.

  • Doubting Thomas

    Jeff Wright – I understand the propellant used in Starship.

    Mike B made the point that I intended on the post. Two flights of Starship could loft the payload module and then propulsion module. With some limited assembly and orbital refueling you could have quite the solar system exploring probe with real scientific capabilities.

  • Col Beausabre

    Jerry, You took the words right out of my mouth. I can remember reading that we would have commercial fusion reactors within about a decade. That was in 1962, when I was ten year old 4th grader and the journal was My Weekly Reader

  • pzatchok

    The new spherical fusion generators look like better designs than the doughnut Tokamac.(SP?)

    But i do think that it would be easier to make a fusion reactor operational in a zero G environment.

    I also think fusion is the only way to get a colony ship out of the solar system and into the next one. I do not think we have enough fissionable material to get there.
    We can build up speed inside the solar system over a long time but we need the power to stay alive from here to there. Its pretty dark out there between the stars.

  • Jeff Wright

    To Jay…water is plentiful…so hydrogen is the future—not the past. Now, if we can find a way to flash ammonia into hydrogen quickly…

    Oh, Stratolaunch dropped a Talon sim.

  • Gealon

    pzatchok; Actually pulsed nuclear fission drives would be sufficient to get to other solar systems, just a little slower than a fusion drive. You should look up Issac Arthur on youtube. He has several videos which step through the different types of propulsion systems and the math involved which shows that fission is perfectly viable for interstellar travel.

  • wayne

    Ammonia as a Hydrogen Source for Fuel Cells: A review

  • Star Bird

    Until we find some Delithum Chrystals Nuclear will have to be used

  • pzatchok


    I have seen the idea. I just do not like basic idea.

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