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Orion Drive space battleship


Nyrath

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Re: Orion Drive space battleship

 

It's been done. In more than one way.

 

(By the way, sorry for the cheat. I couldn't find reference to the Poul Anderson(?) short story with Boy Scouts in spaceships, so I referenced one of A.E. Van Vogt's more craptacular "fix ups," in which no reviewer I could find sees fit to mention the truly ridiculous passage in which Earth turns out to be using Boy Scouts to man its spaceships, because teenaged boys are more warlike than grownups.

(Given when it was written and the tone, I'm surprised that I didn't learn that they also smoked "reefers," but I guess you take what you can get.)

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Re: Orion Drive space battleship

 

The other night I had a dream someone was showing me a new spaceship model (actually two ships). The ships looked a lot like the Orion battleship, but the body was much longer. The models were about 2 feet long. The neatest part was that these ships, since they could fire on each other, like playing laser tag; just press a button. It seemed a bit anticlimactic to knock out the enemy ship with a single shot, but it had some possibilites for a starship combat game. Except you'd need a really big table to play.

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Re: Orion Drive space battleship

 

So I decided to resurrect this thread to post this, as it was inspired by the "Mars by 65, Saturn by 70" thread but the design, which has been building in my head for quite a while, is using 21st C tech, so I thought it'd fit better here.

 

Anyway I give you one hastily assembled first draft of an Orion drive ship designed to head for the Asteroid Belt dropping off linear accelerator stations along its flight path to help "throw" rocks home.[ATTACH=CONFIG]38729[/ATTACH]

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Re: Orion Drive space battleship

 

Anyway I give you one hastily assembled first draft of an Orion drive ship designed to head for the Asteroid Belt dropping off linear accelerator stations along its flight path to help "throw" rocks home.[ATTACH=CONFIG]38729[/ATTACH]

Nice idea. But better don't use the water as Radiation shielding:

Normal hyrogen (protium, what our normal watter is made of) tends to catch neutron and get's deuterium (poisinous in higher concentration) and finally tritium (poisionous and radioactive) when exposed to radiation.

Lead is one of the few material (the only one I know) to know develop this "secondary radiation" and ingesting increased amounts of deuterium and tritium (both exist naturally) is not really a good idea....

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Re: Orion Drive space battleship

 

Nice idea. But better don't use the water as Radiation shielding:

Normal hyrogen (protium, what our normal watter is made of) tends to catch neutron and get's deuterium (poisinous in higher concentration) and finally tritium (poisionous and radioactive) when exposed to radiation.

Lead is one of the few material (the only one I know) to know develop this "secondary radiation" and ingesting increased amounts of deuterium and tritium (both exist naturally) is not really a good idea....

Yeah the problem with finally deciding to put the idea on paper at 2 AM is you occasionally leave out notes about obvious things :P

Ice makes for a decent back up particle sheild, hence wrapping it around the main crew module helps increase its "Storm shelter" aspect

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Re: Orion Drive space battleship

 

It's pretty easy to seperate out deuterium and I assume tritium is even easier. Thunderfoot had a video where he showed water that froze at difference temperatures and ice that sunk in water.

. The heavier water was, well, heavy water i.e. water made with deuterium. This means you can just freeze the water to seperate the isotopes. You may have to do this a few time but it's not that hard. Especially since deuterium is a great feul for reactors. Heck you can even separate it by centrifuge which is basically just spinning it. This is a lot easier than seperating say, U-235 and U-238 since deuterium is almost twice as heavy as protium.
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Re: Orion Drive space battleship

 

Yes, that seems a valid idea.

Just checked on the oxigen part and apaarently all the instable/radioactive isotopes have a halve life time of seconds or less.

 

But I still think lead shielding is better in mass/absorption ratio, can't melt away that easily if the cooling fails and you don't have the problem of drinking/burning away your radiation shield.

Useability as fuel is only given for Fusion reactors and the lack of fusion is the reason whe have to use atom bombs in the first place.

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Re: Orion Drive space battleship

 

Hmm. I knew heavy water was hazardous in large concentrations, but it never occurred to me before to think about heavy water coming from the heavy but stable O isotopes rather than D. O16/O18 is about 500, O16/O17 is about 2400, in terrestrial material, while H/D is about 667. Concentrating heavy water by freezing isn't going to select either heavy H or heavy O preferentially, I think ... hmmm ... well, the moment of inertia of the molecule will be differently affected ... Time to go review the physics of freezing liquids.

 

FWIW, the ice shielding around the reactor/bomb module is probably not a good source for drinking water, but it is about as nice a source for artificial generation of helium-3 as you could ask. Bombard water with neutrons and you'll get some tritium, which decays with a half-life about 12.3 years to He-3. With a large enough mass of ice, most of the He will be bound inside the ice and you can recover it by melting the ice and capturing the gas released. It takes patience to wait for that decay, but I suspect that the ice shielding is a structural thing that stays on a spaceship for a decade or two and gets replaced in the periodic refit.

 

I strongly doubt that makes spaceships a net source of He-3 (if you're using cheap fusion bombs as the propellant), but you can get some He-3 this way.

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Re: Orion Drive space battleship

 

I was just checking back if the the Oxigen could get radioactive by itself, but that is a non-issue. Even if we get stable Oxigen isotopes richer on neutrons, it has way less effect on the biochemistry (Deuterium is so far the only with mayor differences, because it twice as heavy as Protium).

 

While wikipedia has a sentence about Heavy-oxygen water, there is no mentioning of H2 + o16/o18 heavy water.

 

Yes, freezing is not a good way to seperate heavy and non heavy water and centrifugtaion is even less. One way is a distilling it a lot. The other is to use a chemical process. especially the later is used, since it cost's less energy.

 

I don't think you would really try to get He-3 as byproduct of military vessels. Perhaps just building the same thing in large on a planet/moon is more effective ("So, what vintage goes into your tank?"). Or harvesting He-3 from space/gas giants.

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Re: Orion Drive space battleship

 

The neutron capture cross-sections of O16 and O18 are really tiny, tenths of millibarns. Much larger for O17, about half a barn. Hydrogen is a third of a barn. But O17 is about one part in 2400 of the O, while there's twice as many H's as O's.

 

I don't think you'd do neutron bombardment of ice as a "practical" method to get He3, just noting that if you did it right you'd get He3 from water-ice shielding around a reactor like that. If you can store the old shield ice for a century or so, you can get the He3 really, really cheaply, as long as you bothered to do it. Heh, it probably shouldn't be that hard to guess how much you'd get, either, thinking about it.

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Re: Orion Drive space battleship

 

I don't think you would really try to get He-3 as byproduct of military vessels. Perhaps just building the same thing in large on a planet/moon is more effective ("So' date=' what vintage goes into your tank?"). Or harvesting He-3 from space/gas giants.[/quote']

Well it seems Uranus is pretty gassy:

http://news.discovery.com/space/project-icarus-helium-3-mining-uranus-110531.html

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