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Orion Drive space battleship


Nyrath

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Re: Orion Drive space battleship

 

The wiki article is...interesting, to say the least. The 8,000,000 ton version would involve using 1080 warheads, the yield isn't stated, but extrapolating from the given amount for the smaller versions, 250-300kt per bomb sounds about right. That's a lot of mid-range nukes to use for a "one and done" launch platform. One of the interstellar ideas proposed by Freeman Dyson involves a 40,000,000 metric ton ship which uses 30 million one megaton bombs to accelerate to a smallish fraction of lightspeed. The cost would be equivalent to one year of US GDP. The more efficient version uses only a few hundred thousand nukes.

 

max speed of an Orion drive might be 8-10% of lightspeed. But the amount of nuclear material required is simply staggering to contemplate. Now, if you could develop a pure fusion explosion process, this gets a bit more feasible, and if you use similar principles for an anti-matter pulse drive, you can actually get to really impressive speeds(.5 to .8 c).

 

Incidentally, proven global reserves of uranium hover around 5.5 million tons, but obviously there's a world of difference between that amount, and the proportion that is warhead-suitable. Annual production is around 40,000 tons. I'd think we'd run out pretty quickly.

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Re: Orion Drive space battleship

 

When the Nuke Club was five or six I could agree. Now that every Tom' date=' Jong-Il, and Ali have nukes or are on the verge of having them, I am much less certain.[/quote']

 

Proliferation is certainly a threat, I agree. Still, it is really hard to develop nuclear weapons without people noticing, so in theory it could easily be stopped through the judicious application of conventional force. In practice, of course, politics get in the way.

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We're not talking about a few tests' date=' though, right? How many detonations, of what size, would it take to get one of these monsters into orbit?[/quote']

 

For a first generation 4,000 ton spacecraft, it would expend about 800 charges while boosting into a 480 kilometer high orbit. The charges detonated in the atmosphere are about 0.15 kilotons each, the charges detonated in space are about 5 kilotons each. The total amount of nuclear explosives expended is about three megatons.

 

As a comparison, the Hiroshima bomb was about 20 kilotons.

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The entire annual productiones of plutonium is only 20 tonnes' date=' most of which is not currently extracted, and the world stockpile of usable plutonium is only about 500 tonnes.[/quote']

Of course a fast breeder reactor can convert the abundant non-fissile U-238 into fissile plutonium-239.

The only reason there is a lack of plutonium is due to non-proliferation issues.

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Re: Orion Drive space battleship

 

Absolutely. But then again' date=' the EMP effects alone of the orbital detonations involved might annoy more than just the hippies.[/quote']

 

Not really. Since the push charges are relatively small, the range of dangerous EMP is about 170 miles in radius. You just have to have the launch site in a remote spot. Which you'd want to have for other reasons anyway.

http://www.spacedaily.com/news/nuclearspace-03a.html

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For the EMP folks out there, the EMP pulse generated by the size of the munitions uses, is basically nil. We're talking lots of Sub Kilioton level devices here. Not Bomba. There is also a big difference, in what we dropped on Hiroshima, and what we use now. Hells look at where we could have been, 50 something years ago with this thing, and that's not even factoring in that once you sent the BIG Orions over to the moon, they don't have to launch off the earth anymore really, making even the peeps of the hippies a non factor. And that's before, Prometheus comes along, Longshot coulda been a done deal, *sigh* Lot of missed opportunity. *grumbles and goes out to give a Hippy a swift kick in the nads* ......

 

~Rex

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Re: Orion Drive space battleship

 

sub-kiloton for the smaller models, but for the 8MT version, like I said, we're looking at 200-300kt booms, around 1000 of them, at 1 second intervals, IIRC. For the Dyson proposals, I'm not even totally sure there's enough extractable fissile material on Earth for a single mission. But definitely an outside-the-box concept, worthy of note.

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Re: Orion Drive space battleship

 

Mind you, there's problems with atmospheric nuclear explosions even absent biological considerations. If you want radiologically "cold" stuff for whatever reason, a few blasts make that much harder to come by.

 

Astronomers learned this the hard way. Those nice CCD detectors that are in a large number of instruments now ... turns out one limit on those is the presence of silicon-32 in the chip itself. When a nucleus in a solid material decays, it makes for a large deposition of charge into the medium as the nucleus recoils from the decay event, and perhaps also (if it's beta decay) a long string of other ionizations as the ejected particle collides with other electrons in the medium before it finally settles down. All those ionizations make big charge packets dumped at random into pixels in your detector, usually drowning out whatever signal there had been there that you wanted to see. And while chip silicon is chemically pure, the explosion product 32Si is still silicon, and when it's in there it makes for unpleasant events in your data. For a long time these radiation events were called "cosmic rays" because those particles do the same sort of thing to a CCD detector, but when different chips at the same observatory showed wide variation in their "cosmic ray" rate someone finally put a good radiation counter to the chips themselves (and other parts of the instrument around the CCD) and found that it was predominantly the count coming from the chip itself that mattered for the "cosmic ray" rate.

 

Astronomers are a trivial concern, of course, but the increased radiation background is a problem for lots of high-precision metrology tech, since fission products are hardly limited to 32Si. You pay a premium these days for radiologically cold material (lead, steel, etc.) that was smelted before 1945. There are applications where you need it.

 

Maybe I'll play with some back-of-the-envelope numbers about radioisotope yields.

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Re: Orion Drive space battleship

 

Again, the size of the warhead is irrelevant. Almost all the charges discussed are in the range of the W54, a warhead specifically designed for reduced yield, not reduced charge size. You can only make a nuclear device so small, although you can design it to be less effective. That means that there is a mimimum amount of fallout below which you cannot go, and also of the number of charged particles released into the magnetosphere. (Which is the key variable for all those various effects summed up by "EMP" talk.)

The environmental effects of an Orion launch would be enormous, and it is simply not going to work out of the box. If Orion is justified by anything in particular, then we should go ahead with a thorough regime of test flying. The last of our radioactive mutant descendants can throw a party for the astronauts on their way to Alpha Centauri.

 

Now, assembling Orion in orbit is another matter.

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Re: Orion Drive space battleship

 

Now' date=' assembling Orion in orbit is another matter.[/quote']

Which is utterly worthless. :D;)

 

Orion is optimized for surface to orbit boosts.

Once you are in orbit, Orion's low exhaust velocity make it a very unattractive choice compared to the many high exhaust velocity propulsion systems (VASIMR, ion drives, etc.)

 

In other words: the only mission where Orion makes sense is surface to orbit boosts.

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Re: Orion Drive space battleship

 

We have tested PLENTY of Nuclear Kaboom things, and not had any Radioactive Mutants running around, I say go for it. One, you won't know until you try. It's workable, easy, and by all accounts everything you just stated won't happen. The single biggest issue is Just the possibility of fallout in the magnetosphere, and even that's mostly avoidable. You've got more chances of being the progenitor, of a line of radioactive mutant zombies, by racking up frequent flyer mileage on Delta Airlines then what you do with the Orion stuff, and Orion's just the first step to the COOL stuff, and we've blown up more stuff on the ground and underground already another couple of Orions going up carrying everything we need to build on the moon so we don't scare the hippies, and it's all a non issue.

 

~Rex

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We have tested PLENTY of Nuclear Kaboom things, and not had any Radioactive Mutants running around, I say go for it. One, you won't know until you try. It's workable, easy, and by all accounts everything you just stated won't happen. The single biggest issue is Just the possibility of fallout in the magnetosphere, and even that's mostly avoidable. You've got more chances of being the progenitor, of a line of radioactive mutant zombies, by racking up frequent flyer mileage on Delta Airlines then what you do with the Orion stuff, and Orion's just the first step to the COOL stuff, and we've blown up more stuff on the ground and underground already another couple of Orions going up carrying everything we need to build on the moon so we don't scare the hippies, and it's all a non issue.

 

~Rex

 

Try googling "Chernobyl" for more information on Radioactive Mutants.

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Re: Orion Drive space battleship

 

Try googling "Chernobyl" for more information on Radioactive Mutants.

 

:rolleyes:

 

nuclear reactors for general energy use and nuclear (explosives) devices are two completely different animals

 

When a reactor like Chernobyl "blows" it's a 'conventional' and very 'dirty' explosion that spreads alot of "unspent" radioactive material around

 

When a nuclear "bomb" goes off it "spends" most of the radioactive material, the remainder is a very small fraction of the warhead

 

Orion would use the bombs, for the long-term effects of the things Orion would use, just visit Hiroshima and Nagasaki. Both cities not only have been rebuilt, but are larger, more populous and more prosperous than in 1945.

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We have tested PLENTY of Nuclear Kaboom things' date=' and not had any Radioactive Mutants running around, I say go for it. One, you won't know until you try. It's workable, easy, and by all accounts everything you just stated won't happen. The single biggest issue is Just the possibility of fallout in the magnetosphere, and even that's mostly avoidable. You've got more chances of being the progenitor, of a line of radioactive mutant zombies, by racking up frequent flyer mileage on Delta Airlines then what you do with the Orion stuff, and Orion's just the first step to the COOL stuff, and we've blown up more stuff on the ground and underground already another couple of Orions going up carrying everything we need to build on the moon so we don't scare the hippies, and it's all a non issue.[/quote']

 

Did you miss where the big Orion concept requires around 1000 detonations in the 200kt to 300kt range?

 

This isn't about your mythological hippies.

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Re: Orion Drive space battleship

 

:rolleyes:

 

nuclear reactors for general energy use and nuclear (explosives) devices are two completely different animals

 

When a reactor like Chernobyl "blows" it's a 'conventional' and very 'dirty' explosion that spreads alot of "unspent" radioactive material around

 

When a nuclear "bomb" goes off it "spends" most of the radioactive material, the remainder is a very small fraction of the warhead

 

Orion would use the bombs, for the long-term effects of the things Orion would use, just visit Hiroshima and Nagasaki. Both cities not only have been rebuilt, but are larger, more populous and more prosperous than in 1945.

 

Nuclear fission and fusion is not total conversion. The end-products of a nuclear explosion are almost entirely matter, and highly radioactive matter. For example, the fission of an atom of U-235 produces a Strontium-95 atom, a Xenon-139, 2 neutrons, and 139 MeV of energy. Strontium-95 is one of the more notorious components of fallout due to its longterm stability and its biological capacity to be taken up like calcium and stored in the bones. Tritium-3 (the main fusion product) also has a high takeup rate, although it is much less dangerous than strontium, as it does not persist in the body. Both are beta-emitters with relatively long half-lives, and nearly absent in nuclear reactor explosions. This is the whole "don't drink milk for more than year" thing.

The really dangerous components of fallout are the short half-life, highly energetic particles produced by neutron activation. This part is fairly localised, although the sheer quantity produced in an Orion launch (800 detonations in and over the same place in a matter of minutes, versus 500 atmospheric device tests in the whole Cold War) is such as...

Well, in science we are accustomed to unexpected results in novel experiments. I leave it to your imagination what kind of unexpected results this experiment might lead to, but cannibalistic hordes of radioactive mutants are at least as likely an outcome as the "everything will be peachy-dandy" theorising.

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Re: Orion Drive space battleship

 

I've read that the amount of fallout can be reduced by a factor of 10 by using thermonuclear fusion charges instead of fission charges. In addition, the fallout can be reduced by a further factor of ten if the spacecraft is launched near the north or south magnetic poles. This prevents the Earth's magnetosphere from capturing the fallout and returning it to the surface.

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Re: Orion Drive space battleship

 

In addition' date=' the fallout can be reduced by a further factor of ten if the spacecraft is launched near the north or south magnetic poles. [/quote']

 

Although, with the north pole melting apart and the treaties about nuking the south pole, that may be difficult.

 

On the other hand, if you're willing to break the no nukes in the upper atmosphere treaty, then the Antarctica one isn't that much of a threat.

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Re: Orion Drive space battleship

 

I've read that the amount of fallout can be reduced by a factor of 10 by using thermonuclear fusion charges instead of fission charges. In addition' date=' the fallout can be reduced by a further factor of ten if the spacecraft is launched near the north or south magnetic poles. This prevents the Earth's magnetosphere from capturing the fallout and returning it to the surface.[/quote']

 

Wikipedia has a great article on nuclear weapon design, from which I've been cribbing for this thread. As the author says, there is no such thing as a pure fusion device. There are pure fission devices, and fission-fusion devices (cleaner, but not very efficient), and fission-fusion-fission devices. Almost all nuclear devices, even the 155mm shell loadouts, are in the third category, hence "H-bombs." A few from the second category have been tested, including the notorious Tsar Bomba. These produce less energy, because the tamper that reflects the initial fission-produced x-rays back on the tritium payload is made of relatively inert materials such as lead, instead of U-235, or, in the American case (because America is Made of Money), U-238. Unless I've got those two isotopes mixed up again.*

It's all irrelevant, though. You can only scale a nuclear device down so far. After all, otherwise we'd just be setting them off in electrical plant boilers, and all our problems would be solved forever. The charges proposed for Orion are the smallest size practical, nothing but the naked fission "fuze" of an H-bomb, shaped into the least-efficient geometry that will still detonate on implosion --the W54 "Davy Crockett" head, in other words.

The W-54 produces a great deal of short-term fallout for its weight, since it does nothing with the neutrons it produces except transmutation (as I understand it), but significantly less strontium-95. So there's that. But there's no such thing as a "clean" W-54.

As for relying on the Polar regions' less extensive magnetosphere to reduce fallout, remember that we're talking about handwaves from used Orion space battleship salesmen here. Don't be betting the farm on it. Any more than you would on the notion that we could just build an Orion tomorrow and it would work, absent extensive (perhaps even that's-how-long-it-took-to-develop-the-B2 decades) flight testing.

 

 

*Sorry. Overtime hit me on the head again.

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