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The Expanse and its compatibility with OA
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(05-18-2019, 03:04 AM)The Astronomer Wrote: a) droplet radiators! Those are awesome things. Though, I think I've heard of this concept about 'dusty plasma' radiators that seems to be good as well, although I haven't looked into the details yet.

They are indeedSmile I've haven't heard of dusty plasma radiators - a bit of quick googling indicates that they might work even better than droplet radiators (potentially anyway - although some droplet designs also use magnetic fields to keep everything together - but plasma is just so much funBig Grin).

(05-18-2019, 03:04 AM)The Astronomer Wrote: b) for this conversation, I'm referring only to 'near future' ships.

OkSmile

(05-18-2019, 03:04 AM)The Astronomer Wrote: c) To be honest, thermodynamics isn't really a new idea, but I do admit it can easily be forgotten.

To clarify - In the early days of the OA project, images were much harder to come by and the editorial standards were more relaxed. Things have gotten better and stricter on both fronts, which helps with newer images. At the same time, our strong pack rat tendencies tend to make cycling older images out a more difficult process. It does happen, but it usually takes time unless someone takes it upon themselves to push the issue (not fight over it, but bring it up on a case by case basis and keep it top of mind).

(05-18-2019, 03:04 AM)The Astronomer Wrote: As for your question of which ship, the first thing that came to mind is the Starlark. This is a pic of it accelerating in Steve Bower's Starlark with what I assume to be an on-board drive, yet no red hot radiators were shown. Others are such as perhaps most, if not all early interstellar ships in the setting.

Since Steve is active on the forum I'll leave it to him to address the Starlark issue. For other ships, I suppose it would depend on the earlier image factor I mentioned or whether the ship is under power. In some cases, it may be time to archive the current image and replace it with something more realistic. Certainly something we can discuss and if you come across other images that are problematic, please post about them here.Smile

(05-18-2019, 03:04 AM)The Astronomer Wrote: Unless if the OA engineers had found a way to redirect the nasty neutron away from hitting the ship early in the setting (on ToughSF's Discord server, somebody had made a concept on how to direct reaction neutron, I think it was by making sure the fusing atoms' orientation are just right, but I don't know the details), the radiator area is going to be quite big. That, and the drive has to be placed some distance away from the radiation shield.

D-He3 fusion (and p-B as well IIRC) is supposed to produce a much lower neutron flux, so that might be part of the answer. That said, current OA canon for early ships is that they mainly use amat catalyzed fusion which presumably produces lots of gamma rays and possibly some large amount of neutrons.

Some factors that could impact things here are:

a) the performance of the ship - if the ship is only accelerating at .01 to .1 G (or less) it may not need much in the way of radiators. Same if it only accelerates for a time and then coasts most of the way.

b) For advanced radiators - just how big do they need to be. Some time back we were having a discussion around waste heat on reaction drive ships and droplet radiators. I came across a (now unfortunately taken down) page that purported to calculate the performance of a droplet radiator of a given capability and also provide its dimensions. The resulting numbers were amazingly small - which led us to distrust them to some degree. It would be nice if someone could figure out the size of a droplet radiator based on different assumptions - both to help with the relevant EG entries and with image creation.

On a different note - I wonder what, if any, role laser cooling might play in this sort of operation. The waste heat would still need to go somewhere eventually - but the resulting design might look very different from what we are used to. With a high power drive you could siphon off some amount of energy to power a lot of lasers.

Going really far afield in the speculation dept and taking a page from Niven's Ringworld - might you be able to arrange things so that the plasma of the ship exhaust lases in specific spots that fire onto the ship hardware to cool it? With the waste heat from the process ultimately shooting out the back of the ship into space? I suspect there are any number of reasons why this wouldn't work, but throwing it out there anyway - because every now and again I'm surprised and (to quote Clarke) - the only way to find the limits of the possible is to venture a little way past them into the impossible.

(05-18-2019, 03:04 AM)The Astronomer Wrote: I would've mentioned many ships from later in the timeline as well, but well, neutrino coolers. Ship designs after the early interstellar era are really beyond me.

As I said, neutrino cooling is somewhat controversial around here. My preference would be to find other methods, at least for ships made of conventional matter. But be that as it may.

Ok, time to finish lunch and get back to work.

Todd
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RE: The Expanse and its compatibility with OA - by Drashner1 - 05-18-2019, 03:44 AM

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