Cloaking

[JuanBolio]

Funny you would talk about the heat it gives off.. And i total agree with you. But i do seem to recall back in the early days of the B2 that it uses some kind of "exhaust cooling". So maybe some cloaks use something like this.

Unfortunately what works in an atmosphere that has a lot of air around to absorb heat will not work in the vacuum of space. The only place for that heat to go is, well, out into space, where it can be detected by anyone with infrared sensors. Not just the heat from your engines and reactor, but the heat from the life suport and electrical equipment will be clearly detectable as well.

This is why when you see photos of the space shuttle in orbit it always has its cargo doors open - the insides of those doors are the ship's radiators. If they weren't active the ship would quickly overheat.

it's also possible that any extra emissions are being dumped into subspce or another layer of a domain that is not part of actual space in Trek.

Yes, this is the only saving grave I can think of. Dump the heat into subspace. After all, supposedly matter hit by a high-powered phaser beam is "transitioned out of the continuum", so maybe they can do this with their waste heat as well, even if our current laws of physics and thermodynamics say no - the amount of matter and energy in existence from the beginning of the universe on is always constant - matter can change forms or become energy, but it can never go away. Perhaps the universe compensates by dumping an equal amount of gamma rays or tachyons out of black holes... or maybe such theoretical radiation is our universe being bombarded by waste heat and phaser'd matter from another dimension.

SF likely doesn't know where to look for, or individual ships aren't usually configured or powerful enough to detect cloacked vessels, unless they know exactly what to look for.

If there's on thing Starfleet has that are truly excellent it is sensors. They can detect weapons fire in real-time out to a range of several light years, even scan planetary surfaces for life forms across whole sectors. I don't think they'd have a problem picking up what amounts to an infrared neon sign saying "SHOOT HERE!" somewhere within weapons range very, very quickly.

Thank's for the link Juan. I won't argue with your (or the author's) science, but I'm sure there's some BS technobabble excuse in regard to hiding a ships radiation. Maybe a cloaked ship diverts heat and what-not into subspace?

Yeah, as I said above, this is about the only possibility I can think of. It also raises the question of what kind of effect dumping all that phased matter and waste energy into another dimension would have on that said dimension. Are interstellar civilizations polluting and destroying other realms? We already know warp drive can rip holes in the fabric of spacetime and open up subspace rifts...

 

[Crazy Eddie]

No, even the "practical invisibility screen" wouldn't work. You might be able to bend visible light around a ship, but that wouldn't be enough. If you're not dumping lots and lots of waste heat which is visible on infrared, your ship will fry like an egg. All a searching ship would have to do is switch over to the infrared spectrum and the cloaked ship should stand out just as well if not better than by visible light.

That all depends on how you dispose of your waste heat, now doesn't it? The Romulan Bird of Prey has no visible radiators, plus those curious baffles on the ends of the nacelles that could very well serve to restrict IR emissions so you have to be directly behind the ship in order to detect it.

OTOH, I've often played with the idea of a regenerative heating system to recycle the ship's own waste heat for power generation. Line the outer hull with an array of heat pumps, you simply re-capture all that heat and channel it to a turbine for a little extra power. Why dump all that energy into space when you could just as easily reclaim it for a few extra megawatts to your cloaking shield?

Check out this link, if you have the time. Its a really interesting read:

http://www.projectrho.com/rocket/rocket3w.html#nostealth

Read it before. There are ALOT of reasons why the author's assumptions are in error; I am in no mood to go through them right now, but suffice to say, the best case scenario for a sensor system's reliability is NOT a valid argument for how that system must function in combat.

 

[Timo]

..channel it to a turbine..

I have no doubt that Treknology is advanced enough to allow for the "recycling of waste heat". However, that is a pretty advanced trick of scientific magic, and probably any tech that enables the "recycling of waste heat" is better used for making energy out of nothing...

Turbines won't cut it for "recycling waste heat", because they require a cold end in addition to a hot end. You'd still need a separate device for creating the cold. If that device ran efficiently enough, you could turn it into a perpetual motion machine by running its own waste heat to the hot end of a turbine (or other real-world machine). But that calls for an efficiency that's better than absolute, no matter which way you look at it. And as said, tech like that will probably give you your energy boost without the need to mess with waste heat.

Still, nearly perfect heat stealth appears completely plausible even when using real-world tech. Just pump the heat out in a narrow beam, and the enemy has 99.9999% odds of missing the beam. Or store the heat in small pellets and shoot them out at irregular intervals in irregular directions, initially sheathed in cold casings. Even though the heat eventually emerges, the enemy cannot really use it for tracking your passage.

Timo Saloniemi

 

[Crazy Eddie]

..channel it to a turbine..

I have no doubt that Treknology is advanced enough to allow for the "recycling of waste heat". However, that is a pretty advanced trick of scientific magic

There's nothing advanced about a conventional heat pump, Timo. The refrigerator in your house already does this, all it needs is a place to move that heat TO. In a refrigerator, the heat is dissipated into your kitchen; in a starship, it could be dumped right into a heat exchanger.

Nothing magical about that. The way I designed it in the manuscript was that most space craft had networks of tubes filled with a thermal conductive fluid that soaked up heat from the crew, machines, fans, cooked food, etc and pumped that heat into the secondary heat exchanger, which in turn pre-boiled a working fluid that was later pumped through the primary heat exchanger on the way to the main turbine. In this case the entire vessel behaves like a large inhabited boiler in a rankine-cycle generator.

Turbines won't cut it for "recycling waste heat", because they require a cold end in addition to a hot end. You'd still need a separate device for creating the cold.

Only relative cold is required. A simple vaporizer can reduce the fluid temperature to below its own boiling point. Obviously, the mechanisms of the compressors and heat pumps would themselves be very power intensive (since they have to move alot of relatively warm fluid in order to achieve any sigifnigant cooling) but this would still reclaim 10 to 20% of the thermal energy that would otherwise be dumped uselessly into space. The only point of the system is to keep soaking up that wasted thermal energy and turn it back into electrical energy for the ship (especially the cloaking device). It would be more efficient than normal, but hardly "perpetual motion."

 

[StarryEyed]

Thanks for the link Juan. Very interesting stuff.

 

[JuanBolio]

Thanks for the link Juan. Very interesting stuff.

Any time - if only it could prevent newtype_alpha from trying to violate the laws of thermodynamics...alas. The whole site is pretty cool, and has lots of good info on practical starships and spacefaring.

 

[Crazy Eddie]

Thanks for the link Juan. Very interesting stuff.

Any time - if only it could prevent newtype_alpha from trying to violate the laws of thermodynamics...

Can I be blamed if some guy with a website didn't do his homework on how sensor devices are actually used?

 

[JuanBolio]

No, but you can be blamed for thinking that you could find a way to utilize and shield a starship's heat to the extent that it would be undetectable by infrared against the icy nothingness of space without overheating the ship. I'd love to see your math on that one. As for the guy with the website... he shows his work.

 

[Crazy Eddie]

No, but you can be blamed for thinking that you could find a way to utilize and shield a starship's heat to the extent that it would be undetectable by infrared against the icy nothingness of space without overheating the ship.

You could only call that "blame" if I am incorrect. A simple heat pump would suffice for that by channeling thermal energy away from the ship and back into the power systems where it belongs. Humans have known for the past sixty years how to remove heat energy from an closed environment and move it somewhere else.

More to the point: I was referring to AtomicRocket's assumptions about the resolution of even contemporary sensor devices being able to pinpoint the space shuttle's maneuvering thrusters from a range of one million kilometers. The obvious flaw in this assumption is that--as even the author concedes--a full search of a spherical area would require a considerable amount of time if it is conducted at that level of resolution; he fails to acknowledge that the likelihood of your sensors searching that tiny fraction of the sky at the exact moment you happen to be firing your thrusters is remarkably small, and the practical range of any sensor device depends on 1) the smallest object it can resolve and 2) the time it takes to complete a full search of the sky at that level of resolution. The entire logic of stealth in aerial combat isn't that your plane is invisible to enemy radar, it's that the enemy radar has to be a hell of a lot closer than usual to detect it.

Ergo, stealth in space would work exactly like stealth in aircraft and naval vessels. You don't have to keep them from detecting you, you just have to keep them from detecting you until it's too late.

As for the guy with the website... he shows his work.

Which is exactly how I know what he's wrong (and right) about. As for the thermal capacity of a heat pump, unless one of us has suggested some actual parameters for the device, ordinary principle holds. If a refrigerator can cool last night's leftovers without overheating, an internal heat pump can cool your ship without releasing that heat into space.

 

[JuanBolio]

The difference being that in space that heat energy has nowhere to go but...out into space. You can't channel it back into your power systems sufficiently unless you have a thermocouple that is 100% efficient, in which case you'd find you had built a perpetual motion device.

As for doing a sky search at high resolution - as I've stated before, Starfleet has kick-ass sensors... and today we can do it in about four hours using off-the-shelf technology.

 

[SilentP]

A minor aside for the problem of heat and IR signal generation, the game Mass Effect introduces the idea of ships (or at least the hero stealth ship, the Normandy) using heat sinks to absorb the heat into, to reduce the IR signal the ship generated. IT did however have the limitation of only working for a specific amount of time before the sinks themselves went into maximum capacity and the ship would have to 'ground' itself in a planet's atmosphere to dump the excess heat.

The game's background makes a point of the importance of heat buildup, noting that battles can generally end not through the destruction of one side, but one side having to abandon the fight, due to the immense heat buildup threatening to fry the crews inside.

Perhaps the cloaking system in one way can act as a 'heat sink' of sorts, using whatever field it generates to keep the IR radiation within the field, but is limited in how much it can absorb at any particular point, hence why no weapons can be fired, or why going above a certain speed at warp eliminates the effect of the cloak.

 

[Vanyel]

And here I thought the cloak not only bent light around the ship to make invisible to visible light, but was also capable of bending sensor waves around the ship preventing it from being detected; the cloaking field would then be able to mask the ships heat output so that it appears as no more than background radiation.

I also thought that the Federation and the Romulans, and to some extent the Klingons, were locked in a sensor/cloak race. The Federation builds a better sensor, so the Romulans build a better cloak. The cloak on the Scimitar would, eventually, become less effective as Starfleet studied all the sensor information from the 1701E. Without the distraction of battle, Starfleet engineers could go over ever bit of information gathered by the 1701E's sensors and come up with new sensor designs or protocols, then the Romulans would have to up grade their cloak.

 

[JuanBolio]

...the cloaking field would then be able to mask the ships heat output so that it appears as no more than background radiation.

That's nice. How would it do that without keeping all or most the heat within the cloaking field and thus overheating the ship?

 

[Vanyel]

...the cloaking field would then be able to mask the ships heat output so that it appears as no more than background radiation.

That's nice. How would it do that without keeping all or most the heat within the cloaking field and thus overheating the ship?

Doesn't really have to. As I said the sensors beams (or whatever you want to call them) are bent around the cloaking field. The heat is still there, it's just that the sensors are not able to "see" it, because the cloaking is forcing it to "see" what's on the other side.

Starfleet sensors are able to detect cloaked ships that are nearby. In The Defector, I believe, Worf mentions the Warbird is going back into the NZ. Even though the ship is cloaked. So the closer the cloaked ship, the easier it is for the sensors to see it. Once out of range, it's heat output looks like background radiation.

The cloak is so that the Romulans can get in the first shot, maybe even a shot at a ship with it's shields down; and to get away.

I was told before on this board that space is not a good medium to transfer heat; if that is the case, the ship is hot and some of the area around it, but not much else. The cloak only has to cover the area that's hotter than the background radiation of space. At a distance that's easy. Up close, they must shine like stars. However a better cloak, like the Scimitar's, is able to hide it's heat output at even closer ranges.

Not keep it in. Hide it.

 

[Verteron]

What I'd like to know is given all that's been discussed here in this thread, and all I've seen onscreen, how exactly can a cloaked ship travel under impulse power or make thruster manoeuvres without it being absolutely obvious due to a trail of ions or whatever particles the trusters/impulse engines shoot out appearing behind the ship?

There's simply no way to get around Newton's laws here - if you collect up the particles you fire out your engines, the net momentum you gain is zero.

It'd be like trying to blow in to your own sail on a ship...!

 

[Crazy Eddie]

The difference being that in space that heat energy has nowhere to go but...out into space.

Or back into the working fluid that is being pumped into the turbine for power conversion. Remember, heat doesn't have to be distrubted evenly through the entire ship; even without radiating any of it, it's possible (and actually fairly easy) to confine most of that heat energy into a specific vessel (the heat exchanger) where it will do the most good instead of letting it float around the cabin and bake your crew.

You can't channel it back into your power systems sufficiently unless you have a thermocouple that is 100% efficient

Why the hell would I use a thermocouple for that? Just mop up that excess heat using an ordinary heat pump (the same thing that keeps food cool in your refrigerator) and use that to heat the working fluid in a rankine-cycle generator. To simplify this: think of a domestic refrigerator with its radiators locked in an insulated room as it cools things in the refrigerator, the insulated room gets warmer and warmer. If you then run the water pipes from the house through this room, you've got a cheap water heater. If this room gets hot enough to BOIL that water, then you can run the steam through a turbine and turn a generator; you've got electricity.

Heat is a form of energy, after all. If you want to get rid of it without sending it into space, the simplest way is to convert it into a more useful form of energy.

As for doing a sky search at high resolution - as I've stated before, Starfleet has kick-ass sensors...

So do we. But the Atomic Rocket page makes this mistake based on contemporary sensors, and its point is invalid.

Starfleet sensors will also require a certain amount of time to sweep an entire sphere no matter how kick ass they are. By any account, the effective range of that sensor will depend on the lowest resolution the sensors can resolve and long it takes to complete one omnidirectional search at that resolution. Until we know both of these factors, the most you can say is that Starfleet would detect a cloaked vessel faster than the space shuttle would.

 

[Crazy Eddie]

What I'd like to know is given all that's been discussed here in this thread, and all I've seen onscreen, how exactly can a cloaked ship travel under impulse power or make thruster manoeuvres without it being absolutely obvious due to a trail of ions or whatever particles the trusters/impulse engines shoot out appearing behind the ship?

You probably can if you're close enough. But by the time you're close enough to detect it, you're ashes.

 

[JuanBolio]

The heat pumps themselves would generate heat. Even if you managed to isolate the reactors with heat containment systems that were 100% efficient or nearly so, you'd still have the life support to deal with. I just don't think it is at all feasible for a system to be able to hide that much heat from a starship's sensors, at any distance within, say, the diameter of the typical solar system. You'd need to hook up your kick-ass heat pumps to almost every surface of the ship, and those pumps themselves would generate their own heat.

I understand that you disagree and you have some very elaborate theories as to how to get around the problem of stealth in space... but I really think you need to do the math on this if you want to convince me. You say Atomic Rocket is wrong, but Atomic Rocket has some very convincing math to prove itself right. Its going to take math to prove them wrong.

 

[Longinus]

You know, I heard that warp drive isn't possible either!

 

[JuanBolio]

You know, I heard that warp drive isn't possible either!

Really? I haven't.