Nuclear Propulsion - Orion and Beyond

RedStreak · 2006-09-02 13:05:21

People seemed to be yammering on and on about the old Orion nuclear bomb starship idea that it was seriously derailing the Ares versus Ares forum. However since it has become a noteably popular topic I thought to create a forum specifically for the discussion...

The original Orion starship idea, admittedly, uses existing technology for the application of spaceflight, particularly interstellar spaceflight. The major problem that interstellar travel invokes is distance, and that dictates a need to travel faster and that in turn dictates a need for a more energetic propulsion system than current chemical or perhaps even ion propulsion are not up to.

A nuclear bomb, atomic or fusion, is currently the most powerful device created by human beings. Ironically rocket technogy itself is derrived from essentially flying bombs, whether you look to the German V-2 or the ancient Chinese fireworks missiles, so merging these two technologies is kind of fitting.

The Orion concept is sadly out of date and half-baked at best. The advantage of just dumping bombs out of the back port and riding their shockwave is no complex chemical systems - no pumps that could break down during a 40+ year voyage. Downside is the pusher-plate system conceived of would itself break down after withstanding repeated exposure to nuclear blasts - hell just about everything else does too. This involves stopping the ship for repairs just as you might for chemical systems and without a constant thrust pushing the ship you innevitably slow down as the ship, traveling at a slight fraction of lightspeed but still extremely fast, is pummeled by space dust. I am not fond of the idea of launching a craft carrying enough nuclear material to obliterate a good chunk of the planet, safety precautions or not. Also, nuclear material has a half-life - by the time you throw out the 2nd to the last bomb it likely has decayed into useless slag.

Tom Kalbfus · 2006-09-02 17:26:15

The Super-Orion has merit, as I recal it was to use 25 million one megaton yeild thermonuclear bombs and it could reach Alpha Centauri in 150 years.

The small-size 10,000 km/sec ship with a pusher 150 km in diameter and a mass of 240 million tons, would take 30 years to accelerate to full speed, and 150 years to cover the four light years to Alpha and Proxima Centauri, our nearest stars. T reach 10,000 km/sec, 90 percent of the original mass has to be used as propellent, requiring either an extremely light structure, unfolded in space like a spinnaker or a parachute, or the jettisoning or consumption of part of the ship during the voyage, like a steamship burning its furniture as it nears the end of a trip.

Clearly we are talking here about a generation ship, one that does not launch from the ground. I don't know of any other starship proposals that use current technology. I'm sure there is enough fissionables in the asteroid belt to build 25 million thermo nuclear bombs. Traveling to the stars requires enourmous amounts of energy. The warlike potential of any starship is obvious, simply by slamming into the Earth at its top speed, its likely to make a deadly weapon, and the Super-Orion starship is not the deadliest of potential starships! Any sort of interstellar trip requires the harnessing of enourmous amounts of energy, which if place in thw wrong hands can be quite destructive, it just comes with the territory I guess. 25 million H-bombs is greater than the Entire world's combined arsenal, though no doubt we could make such.

SpaceNut · 2006-09-02 17:44:11

As much as I would like to speak knowleably about nuclear use I can not but however there are lots of such threads in the Interplanetary transportation

Covering many of these drive types....

Martin_Tristar · 2006-09-03 00:14:44

Nuclear Explosions are designed to destroy not as a form of propulsion, for long term space voyages we need to work on hyperspace development and other forms of hypervelocity programs.

Remember this " the most powerful force in the universe and binds the universe together is gravity , the understanding of the power could be the key to hyper velocity "

Discover not destroy !!!!!!!!!!

PurduesUSAFguy · 2006-09-03 04:47:46

I get the impression that many people think that Orion was going to us off the shelf nuclear weapons as its 'Pulse Propulsion Units', this was never really the case.

A huge amount of work in the Orion program went into designing pulse units that used near the theoretical minimum amount of fissile material as well as directing the explosion in a much smaller arc the spherical blast of a conventional nuclear explosion. Also there was work done on methods for creating denser plasma, as I recall this involved encasing the warheads in ethylene.

I don't think the Orion system, specifically for ground launch makes a lot of sense using fission, or fission initiated explosions. Weapons grade uranium isn't cheap and isn't even a product the US is capable of producing right now thanks to the short sighted dismantling of our nuclear infrastructure. I do think it might hold promise if/when we have pure fusion nuclear explosives.

GCNRevenger · 2006-09-03 05:33:21

Even then, pure fusion explosives would be expensive to produce on the order of 100s' of units anually and you still wouldn't be able to build a Cape Canaveral for Orions.

PurduesUSAFguy · 2006-09-03 06:08:37

Even then, pure fusion explosives would be expensive to produce on the order of 100s' of units anually and you still wouldn't be able to build a Cape Canaveral for Orions.

Well that's true, but they will still on an order of magnitude cheaper then their Plutonium/Uranium burning counterparts, Lithium6-Deuteride is a fraction of the cost of weapons grade Uranium.

Tom Kalbfus · 2006-09-03 07:32:22

Why wouldn't pure fusion bombs be cheap to produce, especially if you mass produce them and automate the process. Suppose you made a vast factory all staffed with robots putting together bombs one after another. If you eliminate the labor content of the process and you just produce the same thing over and over again, then the only limiting factor is the availability of materials. If you eliminate the need for plutonium or Uranium, what else do you need? Even the avialability of Uranium didbn't stop us from producing tens of thousands of those things.

GCNRevenger · 2006-09-03 10:38:44

I am however a little bit worried about the safety of very large numbers of pure-fusion bombs: the most likely way such a bomb could be made is to use a chemical explosive of unheardof power to compress a magnetic coil and generate a truely monsterous amount of electricity. This would then be fed to the "fusor," another coil, which would compress the fuel to ignition. Electricity moves faster than the explosion, so the fusor recieves the current and causes the fuel to ignite before the bomb is mechanically destroyed by the chemical explosive

Plutonium fission bombs are very safe because they require explosive implosion to detonate, and to accomplish this you require a large number of chemical explosive charges to detonate at precisely the right instant. Since this cannot be done except deliberatly, there is no risk (est 1 in 1,000,000 chance) of accidental detonation. This however would not be the case with such a fusion bomb most likely.

And it would still make a swell weapon, and the mass of chemical explosive, generator coil, and fusor coil would eliminate much of the efficiency bennefit of an all-fusion reaction. And you'd still need the pusher-plate and shock absorbers, and it still wouldn't be any better than a few very large chemical rockets for lift or simpler nuclear engines for transit.

If such a bomb could even be made to work of course.

Tom Kalbfus · 2006-09-03 11:22:24

I think pure fusion devices would be exellent for starships, where you'd be building the ship on a much larger scale. The question is, if pure fusion devices are possible, are they likely to happen even if someone doesn't attempt to build a spaceship that uses them? There are military reasons to build them, and like all technologies, nuke bombs will spread. The question becomes then are will willing to sit still and let ourselfs be wiped out on the same planet as spreading nuclear technologies fall into the hands of religious fanatic that want to destroy us and don't care about dying in the process? I view spreading into space as an escape valve against the treat of impending nuclear fanatacism. I think nuclear fanatacism imperils the planet just as surely as an asteroid on a collision course with us, and the solution ultimately is to diffuse humanity throughout space so that nuclear weapons in the hands of fanatics can't get us all.

Martin_Tristar · 2006-09-03 21:25:18

All the technologies to date about nuclear propulsion 1950's - to today (including the NERVA) are based on the either combustion system and heating the propellant through a nuclear reactor or the explosive power of fusion bomblets exploding using shockwave for thrust. We need to look beyond the simple explosive engine systems and look for a quantum leap of tehnologies into the realm of hyperspace / hyper veolcity drive systems. There is a difference between Intra-solar system missions and Interstellar Missions outside our solar system to beyond.

The development of Plasma drive and Ion Drive are the best hopes for Intra-solar system missions where the development of Hyperspace and Hypervolicty Drive is the best hope for interstellar missions. Nuclear Reactors will be required to power the drive systems and onboard electrical systems but not drive the vessels in space. So lets development the intra-solar system vehicles before thinking about the interstellar vehicles

Conclusion

We development of Power systems as well as drive systems that enhance our space exploration, and these developments must have long term benefits for humanity near earth and beyond our solar system.

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#1 2006-09-02 13:05:21

Re: Nuclear Propulsion - Orion and Beyond

#2 2006-09-02 17:26:15

Re: Nuclear Propulsion - Orion and Beyond

#3 2006-09-02 17:44:11

Re: Nuclear Propulsion - Orion and Beyond

#4 2006-09-03 00:14:44

Re: Nuclear Propulsion - Orion and Beyond

#5 2006-09-03 04:47:46

Re: Nuclear Propulsion - Orion and Beyond

#6 2006-09-03 05:33:21

Re: Nuclear Propulsion - Orion and Beyond

#7 2006-09-03 06:08:37

Re: Nuclear Propulsion - Orion and Beyond

#8 2006-09-03 07:32:22

Re: Nuclear Propulsion - Orion and Beyond

#9 2006-09-03 10:38:44

Re: Nuclear Propulsion - Orion and Beyond

#10 2006-09-03 11:22:24

Re: Nuclear Propulsion - Orion and Beyond

#11 2006-09-03 21:25:18

Re: Nuclear Propulsion - Orion and Beyond

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