# Is this possible? (nuclear propulsion)

**URL:** <https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750>\
**Category:** Factual Questions\
**Created:** [April 10, 2003, 11:20am UTC](https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750 "2003-04-10T11:20:36Z")\
**Posts on this page:** 6\
**Page:** 2

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**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\
**Post date:** [April 11, 2003, 8:36pm UTC](https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750/21 "2003-04-11T20:36:46Z")

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> [@](#):
>
> \*Originally posted by Dr. Zoidberg \*  
> \*\* Of course we would need to miniaturize and spaceproof things like steel mills and smelters. Whether that can be done I don’t know. \*\*

Yup. Back in the 80’s _Discover_ magazine printed an article about an experiment ran on one of the shuttle’s missions. A minature smelter was built which would melt and cast metal on the shuttle. One of the interesting things they discovered was that the resulting casting was _stronger_ than one made on Earth. It’d be a little more complicated to build a lunar smelter than an earthly one, but potentially, the materials yielded could be better than those from the Earth.

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**Author:** ![starman](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@starman](https://boards.straightdope.com/u/starman)\
**Post date:** [April 12, 2003, 9:45am UTC](https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750/22 "2003-04-12T09:45:59Z")

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I doubt you would find materials suitable for fission on the moon, but materials suitable for fusion are in (relative) abundance, if someone comes up with a fusion based system of propulsion.

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**Author:** ![Doomtrain](https://avatars.discourse-cdn.com/v4/letter/d/0ea827/32.png) [@Doomtrain](https://boards.straightdope.com/u/Doomtrain)\
**Post date:** [April 12, 2003, 9:56am UTC](https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750/23 "2003-04-12T09:56:48Z")

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Hmm, so assuming we could overcome all the radiation and such and get this beast airborne (spaceborne?)…what would we do with it? Go to other planets? We couldn’t land the sucker, I’m thinking, so what then? Little exploration vehicle thingies?

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**Author:** ![starman](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@starman](https://boards.straightdope.com/u/starman)\
**Post date:** [April 12, 2003, 10:10am UTC](https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750/24 "2003-04-12T10:10:42Z")

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Depends. If you’re talking a 4000-tonne Orion-sized monster, then I reckon you could afford the space for a landing vehicle or ten.

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**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\
**Post date:** [April 12, 2003, 10:45am UTC](https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750/25 "2003-04-12T10:45:45Z")

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> [@](#):
>
> \*Originally posted by BMalion \*  
> You are now unofficially nominated for the upcoming “Understatement Of The Year Award” 😉

Well, both the British and theoreical physicists have tendencies towards ironic understandment, so no great surprise there. However, I’ve been thinking about this and I don’t see any great problems with what they’re proposing, provided they can get the pellets to detonate in the first place and can control the plasma thereafter. The yield per explosion is only 5 tonnes of TNT, after all. The main engineering problems with Orion were things like radiation shielding and the plasma ablating the pusher plate. I don’t see the shielding as that much of a problem in this case. And in this design the plasma is effectively pushing against some confinement field rather than steel, so you should avoid the latter. At the expense of all sorts of plasma physics headaches, no doubt.  
It’s perhaps worth noting that similar schemes have been proposed before, though usually using fusion rather than fission. The best known is probably the British Interplanetary Society’s Daedalus project

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**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\
**Post date:** [April 12, 2003, 10:58am UTC](https://boards.straightdope.com/t/is-this-possible-nuclear-propulsion/167750/26 "2003-04-12T10:58:08Z")

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> [@](#):
>
> \*Originally posted by BMalion \*  
> You are now unofficially nominated for the upcoming “Understatement Of The Year Award” 😉

Well, both the British and theoreical physicists have tendencies towards ironic understandment, so no great surprise there. However, I’ve been thinking about this and I don’t see any great problems with what they’re proposing, provided they can get the pellets to detonate in the first place and can control the plasma thereafter. The yield per explosion is only 5 tonnes of TNT, after all. The main engineering problems with Orion were things like radiation shielding and the plasma ablating the pusher plate. I don’t see the shielding as that much of a problem in this case. And in this design the plasma is effectively pushing against some confinement field rather than steel, so you should avoid the latter. At the expense of all sorts of plasma physics headaches, no doubt.  
It’s perhaps worth noting that similar schemes have been proposed before, though usually using fusion rather than fission. The best known is probably the British Interplanetary Society’s Daedalus project, in which the pellets were to be bombarded by electron beams. [Another example](http://www.space.com/missionlaunches/launches/fusion_rockets_000719.html).

> [@](#):
>
> \*Originally posted by MegaDave \*  
> Btw, I also heard of a theory where there would be small nuclear explosions set off in front of a ship (possibly several thousand yards in front) and a huge parachute type trap for the fallout. The net effect of this would be that the trap would be attatched to the ship (of course) and would pull the ship along at an ever increasing speed.

This is Johndale Solem’s idea. While the “small” explosions were more Orion-scaled than the 5 tonne ones, the general idea was to go for a smaller, zippier craft than Orion. When I heard him give a talk on the subject about 10 years back, his biggest worry seemed to be the bombs getting jammed in the ejection mechanism, which struck me as one of the lesser engineering problems involved.

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