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-   -   [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull (http://forums.sjgames.com/showthread.php?t=76114)

vicky_molokh 01-06-2011 02:04 PM

[Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Greetings, all!

In preparation for my space campaign, I'm looking over how detection works. There are some things that look either unresolved, or at least not 'doubtless' even if RAW. Specifically:

What is the Heat Signature of a Hot Reactionless drive or Boost Drive? RAW mentions 'as a reaction drive' - how much is that?

Stealth Hull requires a signature of +4 or lower to affect the detection roll. At TL10 it gives -2×(TL-6)==-8. Auxiliary power is a Signature of +3 anyway, unless one is willing to turn off life support (and active sensors, if it matters).

Cloaking Device (SS1:13) says it makes a ship 'invisible' to sensors, but that it can be seen if it fires weapons or uses a reaction drive. Detection mentions -10 (-4 if already detected (?)), and nothing about weapons affecting it. Should that be interpreted as Basic Set Invisibility until weapons/drives use?

Also, the device is energy-intensive, which likely requires having a Fusion or similar reactor active. This puts it at odds with the Stealth Hull, unless it reduces the signature. Nothing gives me reason to believe that it does except my personal idea of what seems sensible. So, if my idea is wrong and RAW is right, a Cloaking Device gives de-facto -20 to detection (negates Plain Sight, and gives -10), plus 5 or more for the reactor. Stealth Hull, by comparison, provides de-facto -8, plus 3 unless one can ditch life support, but doesn't require a system slot, doesn't require power, cannot be disabled . . . but doesn't provide a penalty to being hit either.

Also, should Cloaking Device negate the Silhouetted Against Deep Space modifier (+24)? Again, no indication in RAW that it should, but my hunchy feeling says this isn't necessarily so. If it does, this makes the cloak much, much more desirable.

Answers? Opinions? Suggestions? Comments?
Thanks in advance!

jacobmuller 01-06-2011 02:58 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Heat signature: Hot says it has the signature of a conventional drive. The nearest match for thrust is something like an A-mat Plasma Torch, +10 signature. But it does seem either errata or that you're meant to pick the rating yourself to suit your setting.

Cloaking device: Silhouetted is cumulative with Plain Sight but Cloaking cancels Plain Sight: nothing to see (invisible), so no silhouette sounds logical. So does the "those stars just rippled" line of thought. But I'd go with the Star Trek version.

Crakkerjakk 01-06-2011 03:11 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
I wouldn't allow cloaking devices to eliminate the plain sight bonus.

EDIT: Nevermind, I was thinking of the "silhouetted against deep space" bonus. I wouldn't allow it to negate that.

AM Plasma Torch or Total Conversion Torch have +10 or +11 to detect respectively and the same accel as the hot reactionless, I'd pick whichever number you like the best.

For getting both stealth hull and cloaking device on the same ship, you could use a system of solar panels. But basically a realistic stealth hull is only handy if you're not radiating like a small star.

Mailanka 08-25-2015 08:47 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
This seems the best place to ask (hence my sinister necromancy): Does a Stealth Hull and Cloaking actually stealth? Can you be more invisible than invisible? Super-extra invisible?

I originally thought they could be, but now I wonder. Cloaking seems to imply the maximum possible penalty (you're invisible), but not only can TL 12 stealth hulls exceed that (-12), but it seems they can stack... for a -22 (plus eliminating the plain-sight bonus of +10, giving them effectively a -32 compared to the average ship). Which is fine... perhaps that's the intent, but I just thought I would clarify.

It seems like your spooky "submarine" ships need a stealth hull and some kind of low IR signature system, but while you can run a cloak on a warship, it's not really going to let you get the complete drop on him, especially as you get closer.

vicky_molokh 08-25-2015 09:13 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
At least for normal character-driven Stealth, Kromm said that the In Plain Sight bonus should not apply to a target that is trying to be stealthy in the first place. Not sure whether it's meant to work the same way with spaceships.

Humabout 08-25-2015 11:19 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
It's probably worth considering that there ain't no stealth in space. I think the best way to represent that is to always apply the In Plain Sight bonus, no matter what the ship is trying to do.

Anthony 08-25-2015 11:26 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by vicky_molokh (Post 1930743)
At least for normal character-driven Stealth, Kromm said that the In Plain Sight bonus should not apply to a target that is trying to be stealthy in the first place. Not sure whether it's meant to work the same way with spaceships.

You can't really try to be stealthy in situations where there's absolutely no cover, so unless the ship is somewhere that cover exists (rings of Saturn, cinematic asteroid belt, etc), the in plain sight bonus would always apply. Though I'm not sure the bonuses are quite correct at the moment, I think spaceships may make detection range a bit too high (based on human visual sensitivity, sunlit target in space is about +25 total).

Humabout 08-25-2015 11:34 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Anthony (Post 1930794)
You can't really try to be stealthy in situations where there's absolutely no cover, so unless the ship is somewhere that cover exists (rings of Saturn, cinematic asteroid belt, etc), the in plain sight bonus would always apply. Though I'm not sure the bonuses are quite correct at the moment, I think spaceships may make detection range a bit too high (based on human visual sensitivity, sunlit target in space is about +25 total).

Consider that main engines of the Space Shuttle were visible from Uranus with current technology, though. That range penalty is in the -70 to -75 range (didn't work it out exactly).

Mailanka 08-25-2015 12:23 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Humabout (Post 1930792)
It's probably worth considering that there ain't no stealth in space. I think the best way to represent that is to always apply the In Plain Sight bonus, no matter what the ship is trying to do.

Cloaked ships are certainly not in plain sight, nor are ships in cinematic asteroid belts or in cinematic nebulas. That's how I see it. "In plain sight" is when you're standing around in an open field, only all of space is an open field... except for those listed above. And someone who is invisible is probably not sufficiently obvious to get the "in plain sight" modifier.

Stealth hulls, though, certainly aren't good enough.

Humabout 08-25-2015 12:46 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1930818)
Cloaked ships are certainly not in plain sight, nor are ships in cinematic asteroid belts or in cinematic nebulas. That's how I see it. "In plain sight" is when you're standing around in an open field, only all of space is an open field... except for those listed above. And someone who is invisible is probably not sufficiently obvious to get the "in plain sight" modifier.

Stealth hulls, though, certainly aren't good enough.

My apologies. I was replying to Vicky's post. Specifically that a ship trying to be stealthy shouldn't be considered In Plain Sight. Removing plain sight bonuses for cloaked ships makes sense, since it seems to try to mimic the submarine feel.

Anthony 08-25-2015 12:46 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Humabout (Post 1930798)
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)

weby 08-25-2015 02:16 PM

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.

warellis 08-25-2015 04:21 PM

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?

Ulzgoroth 08-25-2015 04:29 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by warellis (Post 1930888)
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.

warellis 08-25-2015 04:42 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Ulzgoroth (Post 1930891)
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?

Ulzgoroth 08-25-2015 04:44 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by warellis (Post 1930895)
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.

Anthony 08-25-2015 05:14 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by warellis (Post 1930888)
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.

ericbsmith 08-25-2015 05:48 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Anthony (Post 1930901)
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.

safisher 08-25-2015 06:53 PM

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.

Anthony 08-25-2015 09:45 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1930936)
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.
Quote:

Originally Posted by safisher (Post 1930936)
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.

safisher 08-25-2015 10:38 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Anthony (Post 1930975)
Which are completely irrelevant to the problem of stealth in space. At most, it gives options for reducing the reflected signature of a ship.

They aren't completely irrelevant then, are they? And that's what we understand about them right now. Imagine what we will know in the far future, you know, when we have spaceships -- in combat -- with adventurer's on board.

Quote:

We're assuming thermodynamics is true.
And smart folks were assuming all the things that were "science fiction" were impossible, until...every single time...innovations caused paradigm shifts which the average scientist has always thought was impossible. Then suddenly, those things that were impossible were possible. And everyone retroactively knew that, of course. You can cross your arms and say "but this is incontrovertible and you are a fool!" until you are blue in the face. But that doesn't make it so. What it means is that it's possible that TL^ has, and perhaps ultimately will, become TL. And that's all I have said here.

Mailanka 08-25-2015 11:52 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1930936)
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.

Of course we're assuming things will work the way we understand them. Do you expect us to base our assumptions off of what we don't understand? You're talking about known unknowns, and unknown unknowns, and that's certainly true... but it's equally true that nothing will happen that directly invalidates what we know to be true. For example:

Quote:

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 not things that violate our understanding of science, except probably the "reactionless drive" you're talking about, and I really wouldn't hold my breath on that. in fact, if you went back into the 1920s and presented these facts to people then, none of them would be surprised. All of them were already predicted, including your warp drive (the question of bending space has never been whether physics would allow it, but if it was practical... and that's still looking unlikely)

But "stealth in space" is not one of those things. But when we say "Stealth in space is impossible," of course we're slapping an unspoken asterisk of "Unless something happens that we don't know about." What if ships can float around in a lower dimension that makes them invisible to EM emissions? What if they can "translate into dark matter?" What if they can use advanced telepathy to paint their starship in "Ignore me!" telepathy-paint that makes people forget they ever saw it? If we discover something like this, then yeah, sure, stealth in space becomes possible, which is not something GURPS ignores (it's got cloaking devices right there in Spaceships). But until that's discovered:

Stealth in space is impossible*

safisher 08-26-2015 12:13 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931001)
But until that's discovered: Stealth in space is impossible*

There are so many other problems with spaceships as depicted in adventure games it never ceases to amaze me why people want to throw down the gauntlet on this one. But you did it anyway.

Mailanka 08-26-2015 01:01 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931005)
There are so many other problems with spaceships as depicted in adventure games it never ceases to amaze me why people want to throw down the gauntlet on this one. But you did it anyway.

What really baffles me is that there's always someone who's willing to fight to the death to suggest that perhaps there's an element of truth to things like Star Trek (with its nadion beams and its psychic and surprisingly humanoid aliens), and the hill they want to die on is stealth in space.

Why does it matter? Real space combat will look nothing like what you see in "adventure games." It will feature radiators, it will not feature stealth, there won't be any gravity, they probably won't even happen on "ships" at all, and the cute bridge bunny certainly won't wear a skirt.

So? As you point out, lots of adventure games feature that sort of stuff. If we want that, we can play that. I do want that, so I do play it. But does it matter that it's not real? You know that elves aren't real either, right? Do you run into fantasy threads and argue that perhaps one of our cousin races actually managed to survive into the early dark ages and that's the origin of the "elf" myth? Does that even need to be said to justify a fantasy game featuring elves?

There are so many flavors of sci-fi that it's not even funny. I like hard sci-fi, so I spend a lot of time on places like Atomic Rockets and I read up on orbital mechanics and I watch things like Moon. I also like wild and wooly space opera: I love to play FTL or Master of Orion, and I think DS9 is the best Star Trek and I'm baffled and disappointed that Netflix managed to lose Farscape. But I don't need the first to justify the second. They're different genres and they both appeal to me, and I understand how and why they appeal.

Rupert 08-26-2015 03:25 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Crakkerjakk (Post 1102060)
AM Plasma Torch or Total Conversion Torch have +10 or +11 to detect respectively and the same accel as the hot reactionless, I'd pick whichever number you like the best.

I've always used +4 for a 'cold' (standard) reactionless - just enough to stop them being used whilst stealthy (and as you need power anyway, it's largely moot). For hot reactionless drives I use +6, to match a nuclear thermal rocket - I see the signature as being from waste heat, and thus nowhere near what an equivalent reaction engine would put out. One reason was that I'm running a Traveller game, and hot reactionless drives are the standard and I didn't want them so hot that a powered landing by a spaceship was a minor ecological disaster.

I think it's really very much up to the individual GM where they are set.

Quote:

Originally Posted by Mailanka (Post 1930818)
Stealth hulls, though, certainly aren't good enough.

Note that a -8 (TL-10 stealth) means you have to get about twenty times closer to the stealthed ship to detect it. If stealth needs help, I'd say it'd be by raising the threshold at which it stops working, so that low-powered thrusters and power supplies of some sort can be used without negating it.

For stealth that's really hard to spot, you need cloaking. I assume that this is intentional.

vicky_molokh 08-26-2015 03:44 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Humabout (Post 1930792)
It's probably worth considering that there ain't no stealth in space. I think the best way to represent that is to always apply the In Plain Sight bonus, no matter what the ship is trying to do.

Looking over the definition of what In Plain Sight means in a Spaceships context:
Quote:

Originally Posted by SS1:44
+10 if object is in plain sight (in space, air, or
a world’s surface) rather than concealed, camouflaged, hidden
among debris, or using a Cloaking Device.

I wonder if a stealth hull counts as camouflage. Dynamic camo definitely should.

safisher 08-26-2015 08:01 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931018)
What really baffles me is that there's always someone who's willing to fight to the death to suggest that perhaps there's an element of truth to things like Star Trek (with its nadion beams and its psychic and surprisingly humanoid aliens), and the hill they want to die on is stealth in space.

Actually, I'm not fighting to the death. I'm simply suggesting that there is some justification for being a little optimistic about there being the possibility. And the reason for that is because scientists are often wrong. Dead wrong in fact. The future is indeterminate, and using 2015 as the metric for 2315 or 3715 is more than a little conceited, it's lacking in vision.

Quote:

Why does it matter? Real space combat will look nothing like what you see in "adventure games." It will feature radiators, it will not feature stealth, there won't be any gravity, they probably won't even happen on "ships" at all, and the cute bridge bunny certainly won't wear a skirt.
There is no way to know if that is true. In fact, if Alcubierre is right, it might look very different from that. Futurists are notoriously wrong. We need only look at past predictions of the future to realize that.

Quote:

But does it matter that it's not real? You know that elves aren't real either, right? Do you run into fantasy threads and argue that perhaps one of our cousin races actually managed to survive into the early dark ages and that's the origin of the "elf" myth? Does that even need to be said to justify a fantasy game featuring elves?
Please don't be patronizing. And the reason why it matters it because all the "experts" like to run into threads like this and act like they, and only they (with their special secret knowledge) can determine exactly what the future will be.

Quote:

I like hard sci-fi, so I spend a lot of time on places like Atomic Rockets and I read up on orbital mechanics and I watch things like Moon.
I think Atomic Rockets started out with the intent of trying to explain basic rocketry and such, which I enjoyed. There's plenty of use for education. It's now mostly the abode of small brains and fatbeards reciting their high school physic instructors.

Quote:

I also like wild and wooly space opera: I love to play FTL or Master of Orion, and I think DS9 is the best Star Trek and I'm baffled and disappointed that Netflix managed to lose Farscape. But I don't need the first to justify the second.
No one needs science fiction to justify hard sci fi, but we'd be foolish -- and in fact many people are -- to not realize that art inspires science. That is fact. In addition, the greater degree of confidence in such and law, the more likelihood that it will be proven erroneous in some way, or that exceptions exist. That's the operation of normal science. Why so-called science experts can;t understand that is beyond me. Really? You can't imagine how stealth in space could work? How droll. Thank God Einstein and Newton and Hawking had more imagination than that.

Mailanka 08-26-2015 08:40 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931083)
Actually, I'm not fighting to the death. I'm simply suggesting that there is some justification for being a little optimistic about there being the possibility. And the reason for that is because scientists are often wrong. Dead wrong in fact. The future is indeterminate, and using 2015 as the metric for 2315 or 3715 is more than a little conceited, it's lacking in vision.

Why would you be "optimistic" about stealth in space? It's possible or it's not. It's not like its presence or absence would substantially improve our future, or make it grander or more beautiful. I can see the point of being optimistic about FTL travel, or fusion power, or blue-skinned space princesses in cyclopean citadels, pining to be rescued from their six-armed, chitinous captors, but stealth in space is a wash.

I think the word betrays a bias, but the real problem here is how you're arguing. It would be like if there was a flash in the night and a house was destroyed. And someone claimed a UFO did it. When countered that this is nonsense, the person might say "Well, you don't know, it could be." I could almost see that argument, it's the sort of argument we might make for humanoid aliens: We have no evidence that they couldn't be, so they could be.

But what if we found an arsonist who confessed to putting bombs inside the building, and we found further evidence that this was done by human hands, and the UFO-fan snorted and said "Well, police have been wrong before, and confessions can be coerced. It's all a cover-up!"

Well... okay, sure, but at this point you're making claims in the face of evidence, with nothing to actually back it up. What makes your version more likely than the official story? Our evidence points very strongly towards stealth in space being impossible, and for current practical purposes, it's impossible. Thus, for a near-term sci-fi game, the statement "stealth in space is impossible" is perfectly, and based on our current understanding of physics, that won't change when we get to TL 9+, so it remains a valid statement that you can apply to any hard sci-fi setting (as hard sci-fi means "based on our current understanding of science.")

Which brings me back to the "optimistic" slip. I can see no reason to conjecture that there could be stealth in space unless you were heavily invested, emotionally, in there being stealth in space, but that seems an odd thing to invest so heavily in. Why fight this particular fight?

Do you disagree that a realistic depiction of space combat in the near future shouldn't feature stealth? Do you disagree that modern stealth technology has no real application in space combat? Do you disagree that barring a "miracle," an unknown unknown suddenly popping out, that there's no real way to change this in the future? Do you disagree we currently have no practical model for how this would happen, so it must naturally come from something we don't know, our "one miracle" of science fiction?

If you don't, then why are you arguing here? What are you trying to achieve? If you do, could you please elucidate exactly where you disagree?

Quote:

Please don't be patronizing. And the reason why it matters it because all the "experts" like to run into threads like this and act like they, and only they (with their special secret knowledge) can determine exactly what the future will be.
I think this comment speaks strongly to how you feel about the situation. You feel that people who note physics (you complained about people criticizing your incomplete understanding of science earlier) are using "special secret knowledge" to prove you wrong, and when people try to connect, you feel "patronized." If an argument is made against your position, you dismiss it, rather than address it.


Quote:

I think Atomic Rockets started out with the intent of trying to explain basic rocketry and such, which I enjoyed. There's plenty of use for education. It's now mostly the abode of small brains and fatbeards reciting their high school physic instructors.
Just to highlight.

Quote:

No one needs science fiction to justify hard sci fi, but we'd be foolish -- and in fact many people are -- to not realize that art inspires science. That is fact. In addition, the greater degree of confidence in such and law, the more likelihood that it will be proven erroneous in some way, or that exceptions exist. That's the operation of normal science. Why so-called science experts can;t understand that is beyond me. Really? You can't imagine how stealth in space could work? How droll. Thank God Einstein and Newton and Hawking had more imagination than that.
Okay. You're right. Perhaps stealth in space is possible. Show us what it would look like. Explain how it would work.

safisher 08-26-2015 10:35 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931089)
I think this comment speaks strongly to how you feel about the situation. You feel that people who note physics (you complained about people criticizing your incomplete understanding of science earlier) are using "special secret knowledge" to prove you wrong, and when people try to connect, you feel "patronized." If an argument is made against your position, you dismiss it, rather than address it.

This is more of the patronizing approach. It might surprise you to note that a) I have taken a physics course, b) I have read all of the Atomic Rockets arguments, ad nauseum, c) that I clearly understand the laws, as we now understand it, which prohibit the rather simplified issue as described by "there ain't no stealth in space." My purpose on the forums here is not to debate you about the laws of physics; I couldn't care less about what you think about the subject. My purpose is simply to remind the others posting and reading here that hard physics blowhards existed in the 1890s, and were not to happy when Einstein upended their apple carts. Of course 100% stealth in space viewed from all angles at all times is TL^. But there's a lot we don't know about the universe and we are on the cusp, perhaps, of some incredible re-interpretations. This is after all, the point of scientific research. That's why TL^ exists in GURPS. But really, we can already nip away at a total prohibition of stealth with discussions of disguise, drifting without engine power, emitting in one direction away from the enemy, using heat sinks such as ice, etc. Those are "stealth tactics" even if they have very very limited utility in certain very specific circumstances. I say all of this not because I think I have a clue as to how all of this will work out in the future, but rather as someone who has studied the philosophy and history of science, e.g., Kuhn and Popper. Your insistence that I must explain my tentative assertions to satisfy your demands, is well, predictable, and comical. I'll let science do that, perhaps, in due time.

Mailanka 08-26-2015 10:46 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931120)
It might surprise you to note that a) I have taken a physics course, b) I have read all of the Atomic Rockets arguments, ad nauseum, c) that I clearly understand the laws, as we now understand it, which prohibit the rather simplified issue as described by "there ain't no stealth in space."

I believe you.

Quote:

My purpose on the forums here is not to debate you about the laws of physics; I couldn't care less about what you think about the subject.
Then focus on your purpose.

Quote:

My purpose is simply to remind the others posting and reading here that hard physics blowhards existed in the 1890s, and were not to happy when Einstein upended their apple carts. Of course 100% stealth in space viewed from all angles at all times is TL^.
Then we are in agreement.

Quote:

But there's a lot we don't know about the universe and we are on the cusp, perhaps, of some incredible re-interpretations. This is after all, the point of scientific research. That's why TL^ exists in GURPS.
Quite right.

Quote:

But really, we can already nip away at a total prohibition of stealth with discussions of disguise, drifting without engine power, emitting in one direction away from the enemy, using heat sinks such as ice, etc. Those are "stealth tactics" even if they have very very limited utility in certain very specific circumstances. I say all of this not because I think I have a clue as to how all of this will work out in the future, but rather as someone who has studied the philosophy and history of science, e.g., Kuhn and Popper. Your insistence that I must explain my tentative assertions to satisfy your demands, is well, predictable, and comical.
I'm glad I amuse you. But more to the point, you're not really arguing anything at all, as far as I can tell. In fact, it's not clear to me what you're doing at all, other that tut-tutting us for saying that stealth in space is impossible without putting an asterisk of "As far as we know," hurling insults at users of Atomic Rockets, and complaining that I'm patronizing you.

You don't disagree that stealth in space is TL^, or that it's effectively impossible with current understandings of technology. You don't disagree that the various minor tactics that maybe sort of might kind of work are extremely limited and usually impractical for all the reasons someone on Atomic Rockets might cite. And when asked to clarify your position, you refuse to explain, calling such requests "comical" and note your impressive resume (to prove, I presume, why you are above such questions)?

So what are you trying to do? What are the point of your posts? If you're not arguing against our point, what point are you trying to make?

safisher 08-26-2015 11:04 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931122)
tut-tutting us for saying that stealth in space is impossible without putting an asterisk of "As far as we know"...You don't disagree that stealth in space is TL^, or that it's effectively impossible with current understandings of technology. You don't disagree that the various minor tactics that maybe sort of might kind of work are extremely limited and usually impractical for all the reasons someone on Atomic Rockets might cite.

This is what I have said. That seems to be a position that I have communicated, and you have understood. Good for us.

But let me note that the Atomic Rockets very limited stealth exceptions are the camel's nose under the tent -- they really are tactics and while the objectors at that site don't like them, they could in fact be useful under the right circumstances. If it helps it helps -- it's up to future spaceship captains to show how it might work. That knocks right out the blanket "NO STEALTH" argument. Now it becomes "well, okay, but that could hardly help in every situation...and how could that be total 100% stealth anyway?" which is a very bad standard, even for interpreting the way real world radar or sonar stealth is working on the battlefield today. It's a strawman argument on the face of it, basically.

Quote:

So what are you trying to do? What are the point of your posts? If you're not arguing against our point, what point are you trying to make?
See above.

Krinberry 08-26-2015 11:06 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by vicky_molokh (Post 1931052)
Looking over the definition of what In Plain Sight means in a Spaceships context:
I wonder if a stealth hull counts as camouflage. Dynamic camo definitely should.

For my 2 cents, I'd say stealth hulls probably wouldn't count as camo (I'd totally agree the dynamic one should, since that's its point). The 'stealth hull' is, as far as everything in the books suggests, just a 'realistic' design for minimizing signature as much as possible without actually being able to remove it entirely (since as lots of folks have rightly pointed out, there's no ACTUAL stealth in space, just tricks that you can use to help minimize your signature).

Since the stealth hull is more about optimization than actually outright camouflaging, I don't think it would qualify as camo for the purposes of determining plain sight.

jason taylor 08-26-2015 11:37 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
From the narrative(I make no claims for the engineering POV) point of view total invisibility is unnecessary and not necessarily desirable. Better is a sort of limited stealth allowing the hunter and the hunted to parse numerous factors in calculating one another's whereabouts. If invisibility is possible fighting is impossible. If however limited stealth is possible we can have the pleasure of multi hour or even multi day fights like Star trek Balence of Terror, or the second episode of Andromeda.

To do this there are several ways that might come to might. One is a sort of thermal damper that is capable of concealing heat up to a certain point; this might require it to be flushed out every few hours to cool it and the flushing will reveal the ship. Far from being a bug, this is a feature; it allows the rival captains a factor to calculate.

Ulzgoroth 08-26-2015 11:37 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Krinberry (Post 1931126)
For my 2 cents, I'd say stealth hulls probably wouldn't count as camo (I'd totally agree the dynamic one should, since that's its point). The 'stealth hull' is, as far as everything in the books suggests, just a 'realistic' design for minimizing signature as much as possible without actually being able to remove it entirely (since as lots of folks have rightly pointed out, there's no ACTUAL stealth in space, just tricks that you can use to help minimize your signature).

Since the stealth hull is more about optimization than actually outright camouflaging, I don't think it would qualify as camo for the purposes of determining plain sight.

Dynamic Chameleon hull probably should count as being not in plain when in use, yes (at least from adequate distances. But only against normal vision. It has no effect on the hyperspectral (mainly IR) passive sensors that are used to detect spaceships in space.

jason taylor 08-26-2015 11:40 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Ulzgoroth (Post 1931132)
Dynamic Chameleon hull probably should count as being not in plain when in use, yes (at least from adequate distances. But only against normal vision. It has no effect on the hyperspectral (mainly IR) passive sensors that are used to detect spaceships in space.

Most fights will take place outside the range anyway?

Ulzgoroth 08-26-2015 11:57 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by jason taylor (Post 1931133)
Most fights will take place outside the range anyway?

Outside what range?

Krinberry 08-26-2015 12:08 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Ulzgoroth (Post 1931132)
Dynamic Chameleon hull probably should count as being not in plain when in use, yes (at least from adequate distances. But only against normal vision. It has no effect on the hyperspectral (mainly IR) passive sensors that are used to detect spaceships in space.

Yeah, good point! I guess it'd be important to qualify the nature of the detection apparatus when making the call.

Anthony 08-26-2015 12:13 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by jason taylor (Post 1931133)
Most fights will take place outside the range anyway?

Beam combat, if it exists, will almost certainly occur at ranges vastly shorter than detection range. A 99% black hull has an apparent magnitude of 0 (trivially visible) at about 10,000 diameters, and you can increase that range by a factor of 1,000 with quite modest (TL 8 hobbyist) hardware.

jason taylor 08-26-2015 12:31 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Ulzgoroth (Post 1931140)
Outside what range?

The range of the Mark I eyeball.

jason taylor 08-26-2015 12:33 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Anthony (Post 1931147)
Beam combat, if it exists, will almost certainly occur at ranges vastly shorter than detection range. A 99% black hull has an apparent magnitude of 0 (trivially visible) at about 10,000 diameters, and you can increase that range by a factor of 1,000 with quite modest (TL 8 hobbyist) hardware.

Assuming that to be the case(which is dealing with weapons not stealth), the fight STARTS at detection not when shots are exchanged. The captains will have been seeking advantage long before.

Anthony 08-26-2015 12:43 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by jason taylor (Post 1931154)
Assuming that to be the case(which is dealing with weapons not stealth), the fight STARTS at detection not when shots are exchanged. The captains will have been seeking advantage long before.

Eh, that depends on your definition of 'fight', and if you have limited delta-V they may just be coasting. Realistically, space combat tends towards the winner being determined when forces are allocated, and the battle is when you resolve the inevitable (which, despite being inevitable, may be unknown to both parties).

Ulzgoroth 08-26-2015 12:54 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by jason taylor (Post 1931153)
The range of the Mark I eyeball.

Quite possibly, but 'normal vision' includes Telescopic or highly Acute vision that could spot ships, under the right circumstances, at quite long range.

Under typical circumstances that doesn't matter since the thermal IR sensor will have spotted the target much earlier than that.

Anthony 08-26-2015 01:06 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by jason taylor (Post 1931153)
The range of the Mark I eyeball.

Doubtful that the Mark I eyeball is used for detection in space. Cameras with telescopes, however, are likely.

jason taylor 08-26-2015 01:18 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Anthony (Post 1931162)
Doubtful that the Mark I eyeball is used for detection in space. Cameras with telescopes, however, are likely.

Probably not. But I do remember "visual" being mentioned.

David Johnston2 08-26-2015 01:33 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1930984)
And smart folks were assuming all the things that were "science fiction" were impossible, until...every single time...innovations caused paradigm shifts which the average scientist has always thought was impossible.

Hardly every single time. Or even most of the time.

Anthony 08-26-2015 01:44 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by jason taylor (Post 1931164)
Probably not. But I do remember "visual" being mentioned.

'Visual' means something using the visual spectrum, not the mark I eyeball in particular.

Anthony 08-26-2015 01:46 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by David Johnston2 (Post 1931169)
Hardly every single time. Or even most of the time.

Yeah, 99% of the time when physics says 'X is impossible', X is actually impossible. However, that's boring so no-one remembers those instances.

safisher 08-26-2015 02:25 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by David Johnston2 (Post 1931169)
Hardly every single time. Or even most of the time.

It's not what you think.
http://www.newrepublic.com/article/1...bout-certainty

Humabout 08-27-2015 12:24 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1930984)
And smart folks were assuming all the things that were "science fiction" were impossible, until...every single time...innovations caused paradigm shifts which the average scientist has always thought was impossible. Then suddenly, those things that were impossible were possible. And everyone retroactively knew that, of course.

Like practical nuclear space ships producing enough Gs for passengers to be uncomfortably thrust into their acceleration couches? Or what about FTL subspace communications? For that matter, what about FTL propulsion at all? I recall reading a lot of science fiction about time travel, yet that still remains firmly out of reach, unless you've figured out how to create negative energy (energy is, after all, the generator of the time translation genorater in Hamiltonian systems).

Quote:

Originally Posted by safisher (Post 1931191)

Hasn't Carlo Rovelli's Quantum Loop Gravity been shown wrong? Doesn't say much for anything else he's said, especially when it's in the vein of "people should be more open minded."

If you'd like to link to primary research concerning the subject matter, I'll gladly read and consider it. Otherwise, I suppose I've said all I have to say.

safisher 08-27-2015 08:31 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Humabout (Post 1931314)
Hasn't Carlo Rovelli's Quantum Loop Gravity been shown wrong? Doesn't say much for anything else he's said

Newton was wrong. Ignore that guy. Einstein was wrong. Ignore him.
And your contributions are?

Quote:

If you'd like to link to primary research concerning the subject matter, I'll gladly read and consider it. Otherwise, I suppose I've said all I have to say.
Oh, yeah, you've really laid down the law. If we could all be so logical...

safisher 08-27-2015 08:43 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Humabout (Post 1931314)
Like practical nuclear space ships producing enough Gs for passengers to be uncomfortably thrust into their acceleration couches? Or what about FTL subspace communications? For that matter, what about FTL propulsion at all?

Um, yeah. By the time we have nuclear powered spaceships running around at multiple Gs, and not baking the occupants, maybe all the internet experts will no longer be obsessed with explaining why stealth in space is impossible. But probably not.

ErhnamDJ 08-27-2015 08:51 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931375)
Um, yeah. By the time we have nuclear powered spaceships running around at multiple Gs, and not baking the occupants, maybe all the internet experts will no longer be obsessed with explaining why stealth in space is impossible. But probably not.

If, rather than saying that stealth in space is impossible, people regularly chimed into discussions claiming that banking turns in space are impossible, would you object to that claim as vigorously?

safisher 08-27-2015 09:13 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by ErhnamDJ (Post 1931376)
If, rather than saying that stealth in space is impossible, people regularly chimed into discussions claiming that banking turns in space are impossible, would you object to that claim as vigorously?

Please go read up the thread. What I have said is that we might in fact have stealth in space in the far future, for all we know. I find it hilarious that all the posters here want to chime in about how "stealth in space is clearly stupid," while allowing without comment all the other TL^ technological assumptions that get you swooshing spaceships in space in the first place. It's not hard at all to posit reasons why, by the time you have reactionless thrusters, artificial gravity, and and fusion powered spacecraft, you might have very stealthy spacecraft, too. So the vigorous objectors have already come and gone, I'm afraid. Demanding peer reviewed journal article, no less. LOL!

ErhnamDJ 08-27-2015 09:24 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931385)
I find it hilarious that all the posters here want to chime in about how "stealth in space is clearly stupid," while allowing without comment all the other TL^ technological assumptions that get you swooshing spaceships in space in the first place.

Is that what they're doing? "Stealth is impossible in space," seems to assume that we're talking about our current understanding of the world. We could just as easily say, "stealth is impossible whilst detonating hydrogen bombs." This too seems to assume that we're talking about our current understanding.

It may be possible to stealthily detonate hydrogen bombs in the Potomac and, with our current understanding of the way the world works, it seems about as plausible as submarine-like stealth in space.

Could this all be easily avoided by adding a small caveat to the statement? Different people have different understandings of what is physically possible even if we take current understanding for granted. Some people may believe the exotic matter needed for the Alcubierre drive is reasonably possible to procure, whereas other people might not, while both view their beliefs as falling squarely in the realm of hard science.

safisher 08-27-2015 09:30 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by ErhnamDJ (Post 1931386)
Is that what they're doing? "Stealth is impossible in space," seems to assume that we're talking about our current understanding of the world.

I give you a TL^ cloaking device that still makes stealth in space impossible:
http://forums.sjgames.com/showpost.p...7&postcount=12

The mind boggles.

David Johnston2 08-27-2015 09:39 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931385)
Please go read up the thread. What I have said is that we might in fact have stealth in space in the far future, for all we know. I find it hilarious that all the posters here want to chime in about how "stealth in space is clearly stupid," while allowing without comment all the other TL^ technological assumptions that get you swooshing spaceships in space in the first place.

Nobody asked about them. That being said, no, warp drive has not at all moved out of the realm of pure super science seeing as how Alcubierre drive requires an imaginary material with arbitrarily absurd properties

Ulzgoroth 08-27-2015 11:12 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931385)
I find it hilarious that all the posters here want to chime in about how "stealth in space is clearly stupid," while allowing without comment all the other TL^ technological assumptions that get you swooshing spaceships in space in the first place. It's not hard at all to posit reasons why, by the time you have reactionless thrusters, artificial gravity, and and fusion powered spacecraft, you might have very stealthy spacecraft, too.

I find it hilarious that you're trying to make it other people's fault that they took your strenuous assertions about how it's silly to say stealth in space is impossible to be assertions about reality, not superscience.

GURPS Spaceships will cheerfully allow stealth in space with superscience. As, I expect, will anyone posting in this thread. Although, perversely, for best effects you want your ship to have a fuel cell aboard because that (or a solar panel) is the only way to generate power points (allowing you to run the cloak) without invalidating a stealth hull. A cloaked ship can be fairly stealthy, but a cloaked ship with a TL10 or so stealth hull in effect is very stealthy.

(Also perhaps both perversely and reasonably, Cosmic power can make stealth much easier by allowing the cloaking device to run on auxiliary power.)

Anthony 08-27-2015 11:15 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931389)
I give you a TL^ cloaking device that still makes stealth in space impossible:

How is a -10 modifier making stealth impossible?

Ulzgoroth 08-27-2015 11:52 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by warellis (Post 1930888)
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?

Well back in the thread, I said I didn't think there were any rules for that.

I wasn't entirely right about that.

The external radiator design switch includes rules (not very involved or realistic, likely, but rules) for ships overheating when the radiators are retracted, and for using heat sinks to hold off that event. These could provide a starting point to build on.

While I don't see any rules about how that interacts with detection, it would be reasonable to suggest that reactors have reduced heat signature when radiators are shut down. (Rockets probably shouldn't, because of hot exhaust, but that doesn't matter if you're using reactionless.)

If you give that a -2 to signature, fission reactors are compatible with stealth. If you gave a -3 or more, all reactors would be.

Anthony 08-27-2015 12:51 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Ulzgoroth (Post 1931426)
The external radiator design switch includes rules (not very involved or realistic, likely, but rules) for ships overheating when the radiators are retracted, and for using heat sinks to hold off that event.

Thirty minutes before shutdown is probably a bit generous, but it's not absurd. Doing so would normally negate any specific heat signature from the reactor, though your ship will still have a normal signature. Problem is that, well, 30 minutes of stealth isn't very much.

safisher 08-27-2015 12:52 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Anthony (Post 1931421)
How is a -10 modifier making stealth impossible?

Because the rules using sensors to detect it can be construed, as in post #12 in this thread, to make it not actually very stealthy at all. You'll note I posted after that. But whatever.

Anthony 08-27-2015 12:56 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931442)
Because the rules using sensors to detect it can be construed, as in post #12 in this thread, to make it not actually very stealthy at all.

Those rules are just a function of space being really empty. Terrestrial stealth technology, on a surface that's perfectly flat, has no cover, and is almost completely featureless, also does not work very well.

safisher 08-27-2015 12:58 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Ulzgoroth (Post 1931419)
I find it hilarious that you're trying to make it other people's fault that they took your strenuous assertions about how it's silly to say stealth in space is impossible to be assertions about reality, not superscience.

I did put "realistic" in quotes. But this is what is really funny Ulzgoroth, because this is what you said:
Quote:

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.
To which Anthony responded, to a comment about reactionless engines no less:
"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."

Varyon 08-27-2015 01:26 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Ulzgoroth (Post 1931426)
While I don't see any rules about how that interacts with detection, it would be reasonable to suggest that reactors have reduced heat signature when radiators are shut down. (Rockets probably shouldn't, because of hot exhaust, but that doesn't matter if you're using reactionless.)

This won't affect reaction drives, although reactionless likely would be affected, but I'd probably have closing the main radiators reduce IR signature to +3 (equivalent to auxiliary power) or by -2, whichever gives a lower modifier (and with a lower limit of 0, of course). Rather than the ship having 30 minutes to shut down heat generating components, I'd scale the time to what the vessel's IR signature should be. I suspect the 30 minute estimate would be appropriate for a fission reactor, which is +6, so I'd set that as the base. Every +1 to signature would be -1 step on the SSR table to the time the vessel can operate without the main radiators, every -1 would be +1 SSR. So, a vessel running off a fuel cell would be at +2 to detect (normally +4) and would operate for 70 minutes (probably round it to an even hour) with the main radiators closed or destroyed, while one with a cosmic power plant would be at +3 to detect (normally +12) and would operate for all of 3 minutes.

While on this tangent, I'd say that reaction drives with internal reactors (that is, all the ones that require main radiators) are probably at around -1 to detect with the main radiators closed. They last as long as a reactor with an IR signature 2 steps lower - that is, an NTR would be detected at +5 (normally +6) and would operate for 70 minutes (or an hour) with the main radiators closed.

Ulzgoroth 08-27-2015 02:19 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by safisher (Post 1931445)
I did put "realistic" in quotes. But this is what is really funny Ulzgoroth, because this is what you said:


To which Anthony responded, to a comment about reactionless engines no less:
"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 don't know what point you are trying to make, here. Neither of those posts (#17 and 18) are part of the argument about realistic stealth in space that you kicked off in post #19.

Mailanka 08-28-2015 04:25 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by warellis (Post 1930888)
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?

I think Stealth Hull is supposed to represent things like a refrigerated hull. It'd have to, wouldn't it? Having a low radar profile is nice, but not useful if people aren't using active sensors (and by default, active sensors aren't very useful, especially at the ranges we're talking about). You're trying to avoid detection by passive (EM) sensors.

Of course, when you mention "heat sinks" that makes me think of reactors more powerful than the fuel cells that are your default form of power generation for a typical stealth hull (due to the limitation it has on a maximum IR signature). How would people feel about a heat sink reducing the IR signature of a ship?

Varyon 08-28-2015 08:40 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931595)
Of course, when you mention "heat sinks" that makes me think of reactors more powerful than the fuel cells that are your default form of power generation for a typical stealth hull (due to the limitation it has on a maximum IR signature). How would people feel about a heat sink reducing the IR signature of a ship?

A heat sink doesn't store heat, it dumps it. That is, with reactors, the heat sink (main radiator array) is the source of the ship's IR signature. Shutting down the heat sinks should lower your IR signature, and I posted a system for this upthread.

Spaceships doesn't currently have a system for dumping the heat that is built up while the main radiators are closed (presumably, it's meant to be something like "once you open the radiators again, all built up heat is gone," but that doesn't seem realistic). I'd have the radiators be able to handle dumping more heat than the systems normally generate, allowing them to shed built-up heat while the system is still in operation. If a system was filled to capacity, it would take 30 minutes to dump it in this way. If the system is shut down, the radiators can dump heat in half the time. While dumping heat, the vessel is at +2 to IR or a total of +6, whichever is higher (if the systems are shut down, it's at +6 total to detect if dumping at a normal rate, +8 total if dumping at twice normal).

So, let's say we've got a ship with a fusion reactor (+7 IR). If we want to drop this to +3 by closing off the main radiators, it will last for 20 minutes, +20 minutes per full tank of coolant. If the ship has 4 tanks full of coolant, it can stay in stealth mode for up to 100 minutes. At the end of this time, the ship shuts down its reactor and starts dumping heat as fast as possible. It will take 50 minutes to fully flush the system, and it will be at +8 IR during this time. If it instead opted to flush the system while the reactor was active, it would take 100 minutes and leave the vessel at +9 IR.

As for the sort of "heat sink" you're talking about (and that I originally started posting about, before looking it up and finding out a heat sink isn't what I thought it was), a tank of coolant will serve best there. I'd love a more in-depth system for those, but we don't have one currently. The coolant should last an amount of time based on the IR signature of the system(s) being cooled, as well as number of systems. As a first concept, I'd be tempted to say that coolant should be able to cool a single +6 IR system for an hour. Every +1 to IR signature would be -1 SSR to time, every -1 would be +1. Dumping heat would probably follow the above, although with the coolant normally taking an hour to fill it should take an hour to dump (or 30 minutes if dumping it while nothing else is active). For multiple systems, use the average time and divide by the number of systems. For example, take a vessel with 2 fusion reactors, a fuel cell, and a fusion torch. The reactors are each +7 IR (0.7 hours each), the fuel cell is +4 IR (2 hours), and the fusion torch has an internal footprint of +8 IR (0.5 hours). The average is about 1 hour, so divided by 4 systems that works out to 15 minutes per tank of coolant. Superscience coolant should last longer (potentially a lot longer - a cosmic power plant would fill a tank of normal coolant in all of 6 minutes).

Mailanka 08-28-2015 08:52 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Varyon (Post 1931625)
A heat sink doesn't store heat, it dumps it. That is, with reactors, the heat sink (main radiator array) is the source of the ship's IR signature. Shutting down the heat sinks should lower your IR signature, and I posted a system for this upthread.

Spaceships doesn't currently have a system for dumping the heat that is built up while the main radiators are closed (presumably, it's meant to be something like "once you open the radiators again, all built up heat is gone," but that doesn't seem realistic). I'd have the radiators be able to handle dumping more heat than the systems normally generate, allowing them to shed built-up heat while the system is still in operation. If a system was filled to capacity, it would take 30 minutes to dump it in this way. If the system is shut down, the radiators can dump heat in half the time. While dumping heat, the vessel is at +2 to IR or a total of +6, whichever is higher (if the systems are shut down, it's at +6 total to detect if dumping at a normal rate, +8 total if dumping at twice normal).

So, let's say we've got a ship with a fusion reactor (+7 IR). If we want to drop this to +3 by closing off the main radiators, it will last for 20 minutes, +20 minutes per full tank of coolant. If the ship has 4 tanks full of coolant, it can stay in stealth mode for up to 100 minutes. At the end of this time, the ship shuts down its reactor and starts dumping heat as fast as possible. It will take 50 minutes to fully flush the system, and it will be at +8 IR during this time. If it instead opted to flush the system while the reactor was active, it would take 100 minutes and leave the vessel at +9 IR.

As for the sort of "heat sink" you're talking about (and that I originally started posting about, before looking it up and finding out a heat sink isn't what I thought it was), a tank of coolant will serve best there. I'd love a more in-depth system for those, but we don't have one currently. The coolant should last an amount of time based on the IR signature of the system(s) being cooled, as well as number of systems. As a first concept, I'd be tempted to say that coolant should be able to cool a single +6 IR system for an hour. Every +1 to IR signature would be -1 SSR to time, every -1 would be +1. Dumping heat would probably follow the above, although with the coolant normally taking an hour to fill it should take an hour to dump (or 30 minutes if dumping it while nothing else is active). For multiple systems, use the average time and divide by the number of systems. For example, take a vessel with 2 fusion reactors, a fuel cell, and a fusion torch. The reactors are each +7 IR (0.7 hours each), the fuel cell is +4 IR (2 hours), and the fusion torch has an internal footprint of +8 IR (0.5 hours). The average is about 1 hour, so divided by 4 systems that works out to 15 minutes per tank of coolant. Superscience coolant should last longer (potentially a lot longer - a cosmic power plant would fill a tank of normal coolant in all of 6 minutes).

Right, yes, I should clarify. I'm thinking of a system that doesn't use radiators, because it's a ridiculous super science space opera, so the question becomes "How do I justify having a powerful reactor without the IR signature?" So far I'd been using fuel cells, but this discussion of coolant tanks (good catch) made me wonder.

So, you argue that the IR signature comes from the radiators, which makes sense. The rules discussing retracting your radiators seems to be discussing them from the perspective of avoiding damage. If I read you correctly, though, it would also lower your IR signature, because the reason we have radiators is that ships don't radiate IR energy well enough on their own.

Thus, for a spooky, super-science, radiator-less ship, the ship radiates heat well enough without an exposed radiator, but you make the case that it could, instead, choose to dump its heat into a coolant system, reducing the IR signature to, say, +3 for 30 minutes, after which the system starts to overheat

(Super science can, of course, mean anything, but if the only assumption we make is "no exposed radiators" does this pass the smell test?)

Varyon 08-28-2015 09:07 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931631)
So, you argue that the IR signature comes from the radiators, which makes sense. The rules discussing retracting your radiators seems to be discussing them from the perspective of avoiding damage. If I read you correctly, though, it would also lower your IR signature, because the reason we have radiators is that ships don't radiate IR energy well enough on their own.

Thus, for a spooky, super-science, radiator-less ship, the ship radiates heat well enough without an exposed radiator, but you make the case that it could, instead, choose to dump its heat into a coolant system, reducing the IR signature to, say, +3 for 30 minutes, after which the system starts to overheat

Sounds about right. Note you shouldn't need a coolant system for the first 30 minutes - if your ship can dump heat without radiators, but can also opt to stop dumping heat (which should be standard for stealth hulls), you can just follow the main radiator array rules, but without having a radiator that can be targeted at all. In that case, the only addition would be that doing so drops the IR signature. Once it stops being stealthy, it can dump the heat into space - which you could handle as I mentioned, just ignore (yep, radiating again, heat reset, continue on), or have it momentarily "flash" in IR by dumping all that heat at once.

Mailanka 08-28-2015 09:16 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Varyon (Post 1931641)
Sounds about right. Note you shouldn't need a coolant system for the first 30 minutes - if your ship can dump heat without radiators, but can also opt to stop dumping heat (which should be standard for stealth hulls), you can just follow the main radiator array rules, but without having a radiator that can be targeted at all. In that case, the only addition would be that doing so drops the IR signature. Once it stops being stealthy, it can dump the heat into space - which you could handle as I mentioned, just ignore (yep, radiating again, heat reset, continue on), or have it momentarily "flash" in IR by dumping all that heat at once.

Any thoughts on how one would dump all that IR at once?

Anthony 08-28-2015 09:46 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931644)
Any thoughts on how one would dump all that IR at once?

If you're storing the heat in some form of chemical store (such as fuel tanks), you can dump the chemical store. Depending on the nature of your coolant, you might also let it boil away, which will usually only use up some of your coolant.

Ulzgoroth 08-28-2015 10:06 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Varyon (Post 1931625)
A heat sink doesn't store heat, it dumps it. That is, with reactors, the heat sink (main radiator array) is the source of the ship's IR signature. Shutting down the heat sinks should lower your IR signature, and I posted a system for this upthread.

Using 'heat sink' to refer to thermal masses that are used as reservoirs to dump heat into is pretty common. Do you have an alternate term for those?
Quote:

Originally Posted by Varyon (Post 1931625)
Spaceships doesn't currently have a system for dumping the heat that is built up while the main radiators are closed (presumably, it's meant to be something like "once you open the radiators again, all built up heat is gone," but that doesn't seem realistic).

Actually, it does. Page 66. Time with radiators open clears accumulated overheat on a 1-for-1 basis. Whether or not you're still running the hot systems.

Ulzgoroth 08-28-2015 10:17 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931631)
Right, yes, I should clarify. I'm thinking of a system that doesn't use radiators, because it's a ridiculous super science space opera, so the question becomes "How do I justify having a powerful reactor without the IR signature?" So far I'd been using fuel cells, but this discussion of coolant tanks (good catch) made me wonder.

So, you argue that the IR signature comes from the radiators, which makes sense. The rules discussing retracting your radiators seems to be discussing them from the perspective of avoiding damage. If I read you correctly, though, it would also lower your IR signature, because the reason we have radiators is that ships don't radiate IR energy well enough on their own.

Thus, for a spooky, super-science, radiator-less ship, the ship radiates heat well enough without an exposed radiator, but you make the case that it could, instead, choose to dump its heat into a coolant system, reducing the IR signature to, say, +3 for 30 minutes, after which the system starts to overheat

(Super science can, of course, mean anything, but if the only assumption we make is "no exposed radiators" does this pass the smell test?)

I'd say the typical space opera treatment just outright ignores the issue of the heat from the reactor. You can usually detect ships with reactors running more easily, but you do it based on neutrino emissions or something even more hand-wavy, not on the basis of the ship being so hot it glows.

That'd require some fairly heavy reconsideration of Spaceships, though, and doesn't seem to be what you're trying to do.

If you're deciding that the ships do still emit the amount of heat they should be, into normal space, just somehow doing so without anything recognizable as a radiator...which is what Spaceships defaults to, really...I'd agree that having it act like it can retract its mysteriously non-existent radiator for a low-profile mode makes perfect sense.

Optionally, you could make that capability a design option that costs extra, and/or make it a feature only of ships with a Stealth Hull.

Varyon 08-28-2015 11:05 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Mailanka (Post 1931644)
Any thoughts on how one would dump all that IR at once?

You have some sort of superscience technology that can pump out large amounts of heat without any sort of radiator, or at least not a large one. Saying it can actually manage several orders of magnitude more heat than it usually pumps out isn't going to break anything. Failing that, use the same technology to actually build some radiators, and you should be able to dump all that heat rather rapidly. It could have a cool visual effect - the ship momentarily unfurls some hidden radiators, there's a sudden IR spike, and the radiators retract again.

As Anthony notes, actually expelling coolant (or using some way to expel all the heat with a portion of the coolant, either through boiling or through using a heat pump to make what you're expelling super-extra-hot first) is another option. This will give you a limited number of uses of stealth.

Quote:

Originally Posted by Ulzgoroth (Post 1931656)
Using 'heat sink' to refer to thermal masses that are used as reservoirs to dump heat into is pretty common. Do you have an alternate term for those?

They're apparently called "thermal stores."

Quote:

Originally Posted by Ulzgoroth (Post 1931656)
Actually, it does. Page 66. Time with radiators open clears accumulated overheat on a 1-for-1 basis. Whether or not you're still running the hot systems.

Ah, so it does.

RogerBW 08-28-2015 11:17 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Something like David Brin's refrigeration laser might be tempting - if you know where the enemy is, you can send off your surplus heat in a big coherent beam away from them.

Anthony 08-28-2015 11:47 AM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by RogerBW (Post 1931674)
Something like David Brin's refrigeration laser might be tempting.

Sadly, it violates thermodynamics, and if you're going to violate the second law of thermodynamics you might as well just declare you have a device that turns waste heat into useful power, meaning you don't have any heat you need to get rid of in the first place.

RogerBW 08-28-2015 02:07 PM

Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
 
Quote:

Originally Posted by Anthony (Post 1931681)
Sadly, it violates thermodynamics, and if you're going to violate the second law of thermodynamics you might as well just declare you have a device that turns waste heat into useful power, meaning you don't have any heat you need to get rid of in the first place.

Sure, but it does it in a relatively subtle way.


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