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Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

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Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#31

Post by adrianN »

wyager wrote: post #26
moseandre wrote: post #10

Please read Freeman Dysons's "Disturbing The Universe". This book is autobiographical and Dyson explains his arc of passion for nuclear propulsion and Orion. His strongest statement in this book is some deep respect for a biological scientist who, after seeing declassified army training manuals on chemical and biological warfare, supposedly discouraged the entire western hemisphere from further develomepment. This ki…

>This kind of nuclear research is, thankfully, over. Nuclear pulse propulsion is the only currently viable technology that could be used to make humans an interstellar species. It would also allow us to practically ship up enough materials to build self-sustaining habitats in near space. It is extremely unfortunate that this kind of research is over. Fun fact: the background radiation levels introduced by nuclear pro…

I agree that nuclear pulse propulsion would be awesome to have. However, as far as I know radiation hormesis is a hypothesis that is still disputed.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#32

Post by wiredearp »

api wrote: post #4
sien wrote: post #3

Earlier quoted context omitted.

This was considered by project Orion. Basically you turn the vehicle around and use the propulsion to slow you down. It would use a heap of fuel to do this but it was possible. Edit, also, great find of this by the poster.

But since you already used a bunch of your pulse propellant during acceleration, this is partly compensated for by the vehicle weighing less.

In "Death’s End", that’s a science fiction book by Cixin Liu, they use a variant of nuclear propulsion where the nukes are pre-distributed throughout the Solar System instead of being carried by the ship itself. This could free up even more mass and make room for an even bigger magnetic sail to be used for deceleration. Later in the same book, and much later in the fictional timeline, they build a circumsolar particle accelerator, which is easier than you would think [1], and this could be used to produce massive amounts of antimatter in space with a lot more propulsion power than conventional nukes. So I remain optimistic. It’s by the way a remarkable series of books that will freak out a lot of hackers, I recommend sticking with the series to the end.

[1] https://books.google.dk/books?id=A_1oCAAAQBAJ&pg=PA451&lpg=P...

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#33

Post by andygates »

sillysaurus3 wrote: post #2

Happy to see this getting some attention. It's seemed like one of the only viable propulsion methods for interstellar purposes, though nuclear is unfashionable at the moment. I remember seeing a chart showing that it was possible to reach other stars using a technique like this. Unfortunately the problem is slowing down. You could get there, but you'd be going too fast to stop. And since the more fuel you carry, the…

> nuclear is unfashionable at the moment

It's more than that - this isn't just hippies, it's every major power on the planet. To fly Orion you have to put hundreds of nuclear explosives in orbit and pinky-swear that you're not going to use them to obliterate your enemies. Nobody is going to accept that.

Orion's a fun paper rocket but will never be more. Engineers and they "yay nukes!" crowd will drag it out every couple of months for a repost, though.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#34

Post by askvictor »

saulrh wrote: post #23
askvictor wrote: post #22

Eli5: how does a nuclear explosion create a change in velocity for the spacecraft?

Sort of like a sailboat, except the wind is the vaporized material from the nuke. The nuke explodes, throwing a ton of mass and energy in every direction. The rocket uses a sail or pusher plate to catch part of that mass and energy, which carries it forward.

The mass is pretty tiny ( smaller than the ejected fuel pellet); I presume it's the fact it has huge velocity, hence huge momentum? What about photons; do they have the same effect as other particles, or is there a different effect?

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#35

Post by triplesec »

narag wrote: post #28
sillysaurus3 wrote: post #2

Happy to see this getting some attention. It's seemed like one of the only viable propulsion methods for interstellar purposes, though nuclear is unfashionable at the moment. I remember seeing a chart showing that it was possible to reach other stars using a technique like this. Unfortunately the problem is slowing down. You could get there, but you'd be going too fast to stop. And since the more fuel you carry, the…

I remember seeing a chart showing that it was possible to reach other stars using a technique like this. Unfortunately the problem is slowing down. So this is like being concerned how you will spend all that money, once you make it :-) There's a lot of discussion on interestellar travel, but "we" have almost frozen solar system travel. Yes, there are very nice probes out there doing important work, but manned vehicle…

I agree with you in innovation terms, but there's a big economic difference: sailing used free energy and therefore could be developed over the long term by many actors. There are huge energy cost barriers to solar system travel which require bigger bets on economic return to be viable

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#37

Post by simonh »

jharohit wrote: post #19
sprucely wrote: post #11

Earlier quoted context omitted.

That's what Breakthrough Starshot[1] is about, although scaled down to very small probes. I like the probe concept. If we really don't want all our eggs in this one basket, it seems to make more sense to put effort towards tech that can spread our seeds (whatever that may be) rather than humans physically traveling. [1] https://breakthroughinitiatives.org/

Plus, mass driver approach is not the only way to use lasers right? Light can remotely power systems, heat solid propellants to extremely high temperature thus getting better thrusts, etc. So the technology, if scaled up correctly, can be used for large scale transport systems too.

They could be useful for some specific applications, but lasers have very limited effective range as power delivery systems when you're looking at the interplanetary scale. Unless you have very large collectors that is.

For example, for the lunar laser ranging experiment they use telescopes to direct the beam at the moon, but the beam is still 6.5 km wide at the moon's surface.

https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#38

Post by berntb »

andygates wrote: post #33
sillysaurus3 wrote: post #2

Happy to see this getting some attention. It's seemed like one of the only viable propulsion methods for interstellar purposes, though nuclear is unfashionable at the moment. I remember seeing a chart showing that it was possible to reach other stars using a technique like this. Unfortunately the problem is slowing down. You could get there, but you'd be going too fast to stop. And since the more fuel you carry, the…

> nuclear is unfashionable at the moment It's more than that - this isn't just hippies, it's every major power on the planet. To fly Orion you have to put hundreds of nuclear explosives in orbit and pinky-swear that you're not going to use them to obliterate your enemies. Nobody is going to accept that. Orion's a fun paper rocket but will never be more. Engineers and they "yay nukes!" crowd will drag it out every cou…

If you read the book (by Freeman Dyson's son) or even the wikipedia page, you'd know the bombs were quite specialized. And it would certainly be possible to allow some verification (the trigger would not need inspection, that would probably be the really sensitive part, from a technology secrets point of view).

[Edit: The bombs would be directed, throwing light weight molecules up against the pusher plate.]

Also, there is no direct lack of ways to distribute nuclear devices to capitals today, for the countries able to build an Orion. Compare that with the possibility to launch enough material to e.g. start on getting an industrial infrastructure going outside the atmosphere.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#39

Post by berntb »

jaunkst wrote: post #14

If only we could produce anti matter. A tiny amount would provide a fuel source viable for deep space exploration.

When discussing antimatter for propulsion, it might be worth checking out Robert L Forward. I saw the expression that he took the "giggle factor" out of the subject. :-)

I found this overview, discussing a bit about the antimatter research:

http://www.enthea.org/docs/Forward-Emerging-Technologies-Fut...

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#40

Post by [deleted] »

sillysaurus3 wrote: post #2

Happy to see this getting some attention. It's seemed like one of the only viable propulsion methods for interstellar purposes, though nuclear is unfashionable at the moment. I remember seeing a chart showing that it was possible to reach other stars using a technique like this. Unfortunately the problem is slowing down. You could get there, but you'd be going too fast to stop. And since the more fuel you carry, the…

[deleted]
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