10-28-2014, 03:23 PM | #21 | ||
Join Date: May 2005
Location: Oz
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Re: [Spaceships] Orion space drive: launch from underwater?
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10-28-2014, 03:27 PM | #22 |
Join Date: May 2005
Location: Oz
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Re: [Spaceships] Orion space drive: launch from underwater?
Indeed. If the greeblies are using Orion technology the adventure will take branch 2. They will assemble the spaceship underwater, and then when they need to launch it they will float it to the surface (probably with giant airbags), light the blue touchpaper, and be in space before the oppo can complete an orbit.
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Decay is inherent in all composite things. Nod head. Get treat. Last edited by Agemegos; 10-28-2014 at 03:32 PM. |
10-28-2014, 03:50 PM | #23 | |
Join Date: Jul 2008
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Re: [Spaceships] Orion space drive: launch from underwater?
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But you're right, the dry bits could be designed with local sealed containers that into the ship still sealed until conditions during or after launch allow them to be opened. Yeah, I wasn't particularly thinking Orion there.
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10-28-2014, 08:07 PM | #24 | |
Join Date: Nov 2004
Location: The plutonium rich regions of Washington State
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Re: [Spaceships] Orion space drive: launch from underwater?
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Brett didn't specify what form of fusion is being used, but D-T fusion produces neutrons with 14 MeV of energy - this is really quite energetic and can lead to various nuclear spallation processes as well, such as having the neutron knocking off another neutron or proton or alpha particle. These can make make other radioactive particles, which can be the head end of a decay chain of several isotopes before you reach something stable. Lead will be similar in general scope to tungsten, although different in the particulars. Luke |
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10-28-2014, 08:21 PM | #25 |
Join Date: May 2005
Location: Oz
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Re: [Spaceships] Orion space drive: launch from underwater?
Indeed not. I'm trying to cover all possible bases. For what it's worth, D-T seems most plausible. But you might use an expensive and bulky aneutronic launch unit to lob the spacecraft to a safe altitude where its cheap and cheerful D-T pulse units would be not to much of a problem.
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10-29-2014, 07:59 AM | #26 | |
Join Date: Aug 2007
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Re: [Spaceships] Orion space drive: launch from underwater?
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Indeed, in late generation thermonuclear warheads you start out with a minimal fission stage induced by neutrons which makes enough heat to cause a very small D-T fusion reaction to make more neutrons for more fission to make enough heat for a large fusion stage and then you put some cheap uranium in the outside casing to make use of those fusion stage neutrons. You could also insert more fission-fusion stages to make very large bombs. So fusion-only bombs would have to be significantly different. You would need a lot of energy input to bring the whole fusion mass up to temp and you'd really rather not have all those neutrons carrying off 80% of your energy. Any reaction other than D-T needs more energy to start the fusion process but keeps much more energy in the fusing plasma. For fusing of large masses aneutronic might require a smaller net energy input.
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10-29-2014, 07:52 PM | #27 | |
Join Date: Feb 2007
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Re: [Spaceships] Orion space drive: launch from underwater?
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10-29-2014, 08:41 PM | #28 | |
Join Date: May 2005
Location: Oz
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Re: [Spaceships] Orion space drive: launch from underwater?
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I'm putting the adventure on a planet on the frontiers of known/settled space where the human population is either a long-lost and technologically backward colony or a fairly recent and not-yet-extensive colony or an outpost, so it's possible that it might not have been thoroughly surveyed with a fine-toothed comb of ultra-tech instruments. And it doesn't matter if people know that the greeblies have an industrial civilisation down there — in fact I rather think that the adventure has to depend on their being known-of and even having contact with the humans. So if the science is hard enough that greeblies can't have an industrial civilisation in the abyssal depths, then it's probably hard enough that "scanners" aren't magic spaceship detectors that can scour all half-billion square kilometres of a planet's surface in a couple of hours. And if the players won't suspend disbelief in an abyssal industrial but the GM has already established scanners that will penetrate 200m of sea-water, or if the tech of the setting will casually find and recognise a spaceship underwater, of if the campaign is set in the heart of a well-explored ten-millennium-old empire, or if there are powerful psionics who would detect and recognise the greeblies' thoughts of working on a space program? Well, it's hard to write an adventure that can be dropped into any campaign at all.
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10-30-2014, 06:11 PM | #29 |
Join Date: Mar 2008
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Re: [Spaceships] Orion space drive: launch from underwater?
Really good sensors let you detect things. Purified radioactives are rare anywhere. But large things moving underwater and thermal hot spots can be detected but unless you have a good baseline you don't know if that's industrial activity or a whales and natural thermal vents. So if they haven't been monitoring it will take a while to check all the unusual things they detect.
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10-30-2014, 06:30 PM | #30 | ||
Join Date: May 2005
Location: Oz
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Re: [Spaceships] Orion space drive: launch from underwater?
That's true. And super-science sensors are in general better in that way than hard science sensors.
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Decay is inherent in all composite things. Nod head. Get treat. Last edited by Agemegos; 10-30-2014 at 06:56 PM. |
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external pulse, orion, spaceships, subaquatic civilization, underwater |
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