Half a croissant, on a plate, with a sign in front of it saying '50c'
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Nuclear-Bungee Spaceship

Use small nuclear bombs to power an interstellar craft using bungee/cables to linearise the impulse forces
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Right, the maximum velocity for a rocket is pegged at the maximum velocity of its exhaust particles, i.e. there is a velocity at which you start to just drop particles out the back. Also rockets use chemical energy which is somewhat inferior in terms of sheer output compared to nuclear bombs. However, nuclear bombs go bang, in a very short space of time a lot of high speed particles are delivered. The trick is to damp this phenomenon in order to produce acceptable acceleration. ORION used a pusher plate and enormous probably impossible compression dampers. In tension however this becomes a LOT easier.

My space ship will consist of a habitation module with a long length of cable attached to the front of it, this need not be that strong, just be able to take the habitation module under say 3/4g, no problem for kevlar etc. This length of cable will lead to a second module, this will contain the nukes, and crucially a shield designed to completely shade the habitation module a few miles behind it. This module will be attached via large cable drums paying out cable then retrieving it OR bungee ropes (not sure how these would perform under constant irradiation and in space) to a massive parachute-style structure. A nuke will be fired from the shield module into the space in front, explode, provide massive impulse to the parachute structure, cables will be reeled out/stretch then will be wound back in. The whole ship will boing-boing forwards!

bs0u0155, Jun 01 2007

Other uses of bungee cords in spacecraft - Low_20budget_20spacecraft
- somewhere down in the annos [normzone, Jun 01 2007]

Medusa nuclear pulse propulsion http://en.wikipedia...e_propulsion#Medusa
[nuclear hobo, Jun 03 2007]

Orion project http://en.wikipedia...nuclear_propulsion)
Nuclear propulsion - compression type [Cosh i Pi, Jun 05 2007]


       The original design called for nukes to be dropped like depth charges and detonated behind the "vehicle" (not one that I would care to ride in). Your second module defeats any functionality as it is either destroyed by the blast or it is driven into the first module by blast forces.
nuclear hobo, Jun 01 2007

       Even if the habitation module is far enough behind the puller module to be safe, how are your bungee cords going to survive being in the middle of multiple nuclear blasts?
Galbinus_Caeli, Jun 01 2007

       Of course, the advantage of Orion would've been leaving the radioactive debris behind, instead of this idea, where you'd be continually flying through it.
Could do with a few paragraph breaks, and running it through a spelling checker would help
coprocephalous, Jun 01 2007

       //how are your bungee cords going to survive being in the middle of multiple nuclear blasts?//   

       I expect he'll bring some spares.
pertinax, Jun 01 2007

       This makes Orion look almost sensible 8~) but I'd give Orion a pretty big fishbone, too.   

       Apart from any of the considerations mentioned by others, it's quite instructive to calculate the size of bungee cords (or in Orion's case, springs and dampers) necessary to absorb the energy of even quite a small nuke.   

       Hi [bs0u0155] ! That is you, isn't it?
Cosh i Pi, Jun 01 2007

       //Right, the maximum velocity for a rocket is pegged at the maximum velocity of it's exhaust particles, i.e. there is a velocity at which you start to just drop particles out the back.//
This is untrue. Even when the propellant is travelling in the same direction as the craft, there is still an exchange of momentum, and the spacecraft is still accelerated.
ldischler, Jun 01 2007

       [ldischler] You are of course correct. However, the velocity of the exhaust particles is important, because it determines the amount of propellant required to impart a given additional momentum to the rocket. This in turn determines the maximum velocity change that can be achieved using a given mass of propellant. Since the rocket has to accelerate all the propellant it's going to use later, the amount of propellant required increases exponentially with the total of all the velocity changes required for a trip. The exhaust velocity determines the velocity change possible for each doubling of propellant mass.
Cosh i Pi, Jun 01 2007

       I've an idea that this inspired. Rather than making it look like this idea would possibly work, I'll write it as a new idea.
baconbrain, Jun 01 2007

       Anything to do with nukes gets a fishbone from me. And I live in Nuclear Free new Zealand.
Pellepeloton, Jun 01 2007

       //Anything to do with nukes gets a fishbone from me.// Wuss.
nuclear hobo, Jun 02 2007

       [nuclear hobo] I thought for a minute you were aiming that at me! I wouldn't go QUITE as far as [Pellepeloton] - but very nearly. Being a wuss is sometimes the wisest option... (I'm a former nuclear engineer. The reactor engineering branch of the industry puts one in mind of an overexcited class of nursery children with a box of matches in a fireworks factory. Only much bigger.)
Cosh i Pi, Jun 02 2007

       //Anything to do with nukes gets a fishbone from me.// What [nuclear hobo] said; if this was a discussion of nuclear weapons then I'd likely be right with you; we don't need any more of them.   

       However, the only reason nuclear power is present here is for its advantages as a high-density energy storage medium. Being totally against anything that happens to mention the word "nuclear" is a little Luddite, in my opinion.   

       [edit] Oh dear, I do sound harsh. But I feel my point stands - I doubt you disagree with X-ray imaging, for example. Not wanting nuclear weapons or nuclear power is a position I can understand, whether or not I agree with it. But there are positive uses for nuclear materials, and deep space travel seems like one to me.
david_scothern, Jun 02 2007

       I was refering to my *name*.   

       There are no "good" nukes, whether for power generation or for weapons. Either one is only about something else entirely ... nice metaphor, [Cosh i Pi].
nuclear hobo, Jun 02 2007

       1) In a closed system, you can't gain any more 'momentum' going forward than the net total amount of momentum that you have spewed out behind you. Obviously you could do that in an open system if you performed a gravitation slingshot, used solar sails, or refueled by scooping hydrogen as you moved along.   

       2) This idea is like being towed by a series of nuclear detonations, which seems to be highly inefficient since you'd get a perfectly spherical blast in a low gravity low air friction situation. [-]
quantum_flux, Jun 03 2007

       Nah. We definitely do not want the passenger compartment anywhere near the back of this vehicle.   

       How about retaining the original Orion pusher plate, but attach a sort of gallows to it, and "hang" the passengers from a bungie cord there.   

       In that setup you could in fact use two bungie cords, in order to prevent the passengers from smashing into either the plate or the gallows, and your vehicle would then have a real suspension system.   

       Admittedly, this would loose some of the picturesque paddle-board style of the original idea, but I've always held that form should follow function.
ye_river_xiv, Jun 03 2007

       Baked, at least in theory. [link]
nuclear hobo, Jun 03 2007

       Interesting that that Wikipedia article is tagged as not citing sources, but not tagged as controversial. It's astonishingly one-sided in its presentation.
Cosh i Pi, Jun 03 2007

       I think there is a misunderstanding as to what a nuclear blast would be like in space. The carachteristics would be somewhat different than they are within an atmosphere, there would be no massive overpressure which does all the damage on earth. Just a massive burst of EM radiation and a few nice juicy high-energy particles including the vapourised remains of the casing.   

       The large parachute structure would be just that, large 5-6 km of foil-like substance
bs0u0155, Jun 04 2007

       [bs0u0155] Hmm. Agreed about the absence of massive overpressure. However, it's not really quite "a few nice juicy high-energy particles including the vapourised remains of the casing". Only a fraction of the uranium actually undergoes fission, and the uranium is only a fraction of the total mass of the bomb. The fission products' mean free path in the mess is very short, so they heat up the whole mess to a very high temperature, not merely vapourizing it all but turning it into a very hot plasma. You can call that "high energy particles" if you like, and that's a fair(ish) description - but it's worth noticing that they're all MUCH lower energy than the original fission products.   

       Nonetheless, the energy of these particles will still correspond to a very high temperature, and they'll wreak havoc with the molecular structure of you parachute on their way through - I say through, because unless your parachute is unreasonably thick, they won't be stopped. They'll certainly apply some force, but they won't deposit anywhere near the whole of their energy.   

       Incidentally, "casing" is an appropriate term for the non-explosive part of a conventional bomb - which is basically a casing full of high explosive with a relatively tiny detonator. It's much less appropriate for an atomic explosive device, where the nuclear material is a much smaller part of the whole device, and the remainder is mostly not the casing.
Cosh i Pi, Jun 04 2007

       Wouldn't it be easier to simply detonate small nuclear bombs off the back of the craft and get propulsion out of it?
croissantz, Jun 05 2007

       [croissantz] That's the Orion design. This design is to get round some of the problems of the Orion design.
Cosh i Pi, Jun 05 2007

       Wasn't the Pan-Am spaceplane in "2001:A Space Odyssey" called the Orion?
Or is this just any Orion (any any any Orion)?
coprocephalous, Jun 05 2007

       See link for the Orion Project - I've not looked, but to judge by other Wikipedia nuclear articles of late, it's probably a bit pro-nuke, but will doubtless describe the project accurately enough.   

       Don't know about A Space Odyssey.
Cosh i Pi, Jun 05 2007

       Bah. 8~) Didn't even notice the pun, sorry. Should we delete these last couple of annos?
Cosh i Pi, Jun 05 2007


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