liam asked in Science & MathematicsPhysics · 1 week ago

Why wasn't nuclear power used when building space crafts?

6 Answers

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  • 7 days ago

    I'll just list why:

    Danger from radioactivity...to crew and surroundings.

    Very very heavy shielding and nuke fuel, reduces payload capability.

    Still need a chemical fuel to thrust; so nothing gained there.  (See later item)

    Slow response time (e.g., on off) makes controlling problematic.

    If nuke explosion is attempted as thrust, that's way beyond strength of materials limits in heat and pressure.

    Cost of R and D far exceeded that of chemical rocket system.

  • Zirp
    Lv 7
    7 days ago

    It WAS used to build spacecraft on earth, and the machinery of at least one spacecraft IS powered by an on-board nuclear reactor.

    We have not fond a sensible way to use nuclear energy for PROPULSION

  • 1 week ago

    I think primarily: the danger of nuclear radiation in the case of an accident...which accidents were quite common in the 50s and 60s.

    You don't want to be irradiating people - especially your top rocket scientists - if you can help it.

  • Anonymous
    1 week ago

    Well, radioisotope thermo-couple generators have been and are used on some spacecraft. But they don't generate much electricity, and they generate power from radioactive decay and not a nuclear reaction of any kind. 

    Nuclear reactors are big, heavy and require a fair amount of fuel and, not to mention management. It's hard to manage something so sensitive with a few hours delay in communication, like a probe at Jupiter or beyond. 

    But there is currently some big strides in miniaturised nuclear generators, specifically for spacecraft. So we may be seeing those implemented in the next decade or so. 

    But we still haven't cracked energy positive fusion yet.

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  • 1 week ago

    Building? depends on which "space craft" you mean.

    For example, the Apollo command and service module was built by North American Aviation. The electric power used by that company was supplied, as is true for any company, was supplied by a grid of power sources, some of which are oil fired, some hydro based, some nuclear.

    So, bottom line, nuclear power WAS used in building space craft. 

  • 1 week ago

    Historically, because we did not have any way to use nuclear energy as a power source (chemical reaction rockets predate the development of even uncontrolled induced nuclear fission processes or "bombs").  In addition, nuclear power cannot be easily controlled or employed to create a mass/response process (ejection of mass in one direction to impel motion of the rocket in the other), so there are technical and cost reasons.  Finally, there is the hazard issue: failure of a device relying on nuclear fission would cause the disseminated of extremely hazardous fissionable (radioactive) fuel. We cannot do fusion yet, so that is still out as an option.

    If you read older sci-fi literature, you will see that some stories have hypothesized the use of nuclear bombs to drive the motion of spacecraft, but it requires immense shielding and ablative armoring. That was the method used to fly the cities in James Blish's "Cities in Flight" for example, I believe (that is what I remember). Lots of mass and energy involved and requires pulses of energy rather than relying on continuous energy output.  Costly and very risky, and not very practical. Maybe someday we will be able to employ ion-streams fueled by nuclear reactions or something such as that, but we simply are not there yet in technology.

    • billrussell42
      Lv 7
      6 days agoReport

      see the word "building" in the question. NOT propulsion, which is never mentioned. 

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