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PaperclipPerfector  4mo ago (text post)   1937 thread views

Friday Fun Thread for January 5, 2024

Be advised: this thread is not for serious in-depth discussion of weighty topics (we have a link for that), this thread is not for anything Culture War related. This thread is for Fun. You got jokes? Share 'em. You got silly questions? Ask 'em.

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Ah, yeah that sounds like something not particularly stealthy, unless there is some very fancy nozzle tech going on.

The Voyager example is cited alot as some sort of definitive proof, but misses the obvious point that emissions controls (EMCON) on radio frequency emissions have been a means of avoiding detection since shortly after the first RDF equipment was invented, and the navies and air forces of the world have practiced its use for nearly a century at this point. A 20 watt RF emission is infinitely stonger than a non-existent one after all. The great thing about a vaccum is there are no pesky particles to scatter lasers, which means laser LOS communication is quite easy, and i would imagine become the default for military operations.

RE lasers as radiators- the basic recipe for a laser is to convert an incoherent form of radiation to a coherent form, with some transformation losses of energy. These tranaformation losses are usually waste heat, but if you are beaming a massive amount of IR radiation away, your thermal energy delta is negative. Gas dynamic lasers are a good example- they can arc weld quarter inch steel plate at a hundred miles in a fraction of a second, and the lasing mechanism itself becomes only slightly warm to the touch. There is definitely no free lunch in terms of energy generation, but since the problem you are trying to solve is an energy surplus rather than a defecit, thats not a particularly big deal. The simplest setup would involve a a solid state IR laser enveloped by a cooling mechanism which is in turn coupled to some form of thermionic converter that is the actual power source for the laser. This makes for what is effectively a laser refrigerator of not particularly great efficiency, but still capable of cooling a spacecraft while emitting only coherent radiation.

There is not a whole lot of literature on the subject, mostly because lasers dont make very efficient radiators and the only immediately plausible applications are all military in nature, but there is no thermodynamic prohibition on it. See: https://ntrs.nasa.gov/citations/19660023147 for the genral efficiency calculations.

The FTL interaction with stealth is definitely an interesting one, I find the way its portrayed in the Honor Harrington series to be good, essentially concluding that in a universe with relatavistic ships and weaponry anything moving in classical mechanic terms is stealthy because the light cone of detection is slow relative to the application of deadly force.

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