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Old 08-25-2015, 11:46 AM   #11
Anthony
 
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

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Originally Posted by Humabout View Post
Consider that main engines of the Space Shuttle were visible from Uranus with current technology, though.
Probably not if it's on the ground, actually, but the separate issue is that the drive signature modifiers are a bit off (the SSME should have a total signature of around +24)
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Old 08-25-2015, 01:16 PM   #12
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

I get best overall results by ignoring "in plain sight" as modifier and giving a flat +10 to vision and sensor based detections where you take the time to do them. It is not perfect but it does have the effect of not having that sudden x50 jump in efficiency.

As for the stealth hull/cloaking and such: I specifically ignore the signature limits and allow the bonuses in all cases. That is not meant as realistic but as gameable.

Cloaking device: In my games it just gives a flat -10 for all sensor and vision rolls and is cumulative with stealth hull, you are still otherwise normally visible. It is generally available at TL 11^, but will have problems with too varied backgrounds, so gets full effect only when the silhouette against space.
In the upcoming big scifi campaign it will be only useful against the silhouette modifier and will raise in price as the size of the ship increases to mainly make it a feature of small vessels like scout ships and fighters.
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Old 08-25-2015, 03:21 PM   #13
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

If one has reactionless engines, a refrigerated hull, & some form of heat sinks, how much easier is it to have some type of "stealth" in space?
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Old 08-25-2015, 03:29 PM   #14
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

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If one has reactionless engines, a refrigerated hull, & some form of heat sinks, how much easier is it to have some type of "stealth" in space?
Do we have rules for that? I can't think of any...

The major problem with stealth, coming from the GURPS side, is that even with cool reactionless you need to get power from somewhere. And just about all power sources will blow your heat signature past the stealth threshold on their own.

EDIT: If you've got the switch where reactionless drives don't require power points to run, you're golden.
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Old 08-25-2015, 03:42 PM   #15
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

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Do we have rules for that? I can't think of any...

The major problem with stealth, coming from the GURPS side, is that even with cool reactionless you need to get power from somewhere. And just about all power sources will blow your heat signature past the stealth threshold on their own.

EDIT: If you've got the switch where reactionless drives don't require power points to run, you're golden.
Hm can't they magically cram even the heat from a reactionless engine into some heat sink somewhere for a few hours or days or whatever?
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Old 08-25-2015, 03:44 PM   #16
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

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Hm can't they magically cram even the heat from a reactionless engine into some heat sink somewhere for a few hours or days or whatever?
It's not the heat of the reactionless engine. It's the heat of the power plant that allows you to run the reactionless engine.
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Old 08-25-2015, 04:14 PM   #17
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

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If one has reactionless engines, a refrigerated hull, & some form of heat sinks, how much easier is it to have some type of "stealth" in space?
Assuming your heat sinks are magical, you can suppress your IR output by quite a lot. The problem is that any realistic heat sink will fail in a very short time scale if used to keep your hull cool.
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Old 08-25-2015, 04:48 PM   #18
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

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Assuming your heat sinks are magical, you can suppress your IR output by quite a lot. The problem is that any realistic heat sink will fail in a very short time scale if used to keep your hull cool.
I think the best idea along those lines was called a Hypersink in one of the Vehicles Companions - it essentially allowed you to dump your waste heat into hyperspace and thus keep your IR signature low when cruising around in normal space.
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Old 08-25-2015, 05:53 PM   #19
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

A couple of thoughts here. First, in the "realistic" approach, we have just begun to tip our toes into metamaterials. The advances made in this field are taking us into GURPS TL^ territory. Everyone now screaming that "there is no stealth in space" assumes that everything works in the far future as we now understand it. Fine. But that's probably not very realistic.

Metamaterials, for instance, are proving that cloaking, fixed antennas which work like steerable ones, and a host of other applications will provide opportunities for things to work very different today than in the far future. Thus, there's very little "realistic" about trying to dispense with stealth or cloaking in space. This is like pointing to classic sci-fi with steel helmets and laser guns and saying that's the only realistic path forward.

And while others are going to jump on this and rail about my poor understanding of science, remember that warp drives are now no longer strictly a superscience consideration, and recent tests in fusion power and may make reactionless powered spacecraft possible in the near term. These are things real scientists are researching right now. However it all works, it's not unrealistic to propose that the idea of cloaking may be used in space. It may very optimistic, and it probably will look very strange to us, as the geometries involved may be very unusual compared to stock sci-fi swooshing spaceships.

http://www.nytimes.com/2015/03/24/sc...ials.html?_r=0

https://scholar.google.com/scholar?q...IVijySCh3lsAoD

https://scholar.google.com/scholar?q...0%2C4&as_vis=1

Second, if you want a superscience TL^ cloak, make it so. Wipe out all range, background, and other factors. Simply apply the -10 solely to the operator's skill. The end. A highly skilled operator might detect your cloaked ship, but otherwise, you are cloaked. End of story. You don't need any more justification than that.
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Old 08-25-2015, 08:45 PM   #20
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Default Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull

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A couple of thoughts here. First, in the "realistic" approach, we have just begun to tip our toes into metamaterials.
Which are completely irrelevant to the problem of stealth in space. At most, it gives options for reducing the reflected signature of a ship.
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Everyone now screaming that "there is no stealth in space" assumes that everything works in the far future as we now understand it.
We're assuming thermodynamics is true.
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