Tac-nukes vs. Nuclear Warheads

[Clonus]

Re: Tac-nukes vs. Nuclear Warheads

 

I think you have not thought things out fully. If the hull does not radiate any heat' date=' this means that any heat generated inside the hull will stay inside the hull. This includes waste heat from the power plant, drive, and the body heat of all the crew members [i'](if you have been stuck in a closed room with too many people you know what I mean)[/i].

 

So the temperature will eventually rise to a point where the bulkheads will start glowing, all flammable objects will catch fire, and the people will die agonizing deaths.

 

But that offers a pretext for the scene where in order to sneak up on someone you take your interior temperature down to the minimum possible and then go to "silent running" by making your final manuever, and then coast for hours as the ship slowly and steadily heats up until, by the time you are ready to launch your surprise attack, everyone's in their underwear like in that Kraft Dinner ad where the dorks use their dorm radiator to prepare their meal.

[Spence]

Re: Tac-nukes vs. Nuclear Warheads

 

So read the Honor Harrington novels by David Weber. His FTL system enforces broadsides.

 

 

[AmadanNaBriona]

Re: Tac-nukes vs. Nuclear Warheads

 

If you are moving near the speed of light (or any appreciable percentage of said speed) then the light (heat' date=' rf, uv, etc...) will head away from you at the speed of light, but be doppler shifted in wavelength due to your speed. Neither you, nor the light you give off will appear to violate the speed of light in any frame of reference.[/quote']

 

Nothing personal, but I wouldn't EVER bet a penny against a pound when it comes to Nyrath being wrong about something related to spacecraft or future tech.

[Nyrath]

Re: Tac-nukes vs. Nuclear Warheads

 

Nothing personal' date=' but I wouldn't EVER bet a penny against a pound when it comes to Nyrath being wrong about something related to spacecraft or future tech.[/quote']

Thanks for the complement, but I have been wrong in the past.

 

It is just that owning a such a public website with my future tech data on it, if I do get something wrong, I quickly receive lots of email from the experts pointing out my mistakes.

 

In other words: I go through the suffering of trying to learn all this junk and making silly mistakes so you don't have to.

[Nyrath]

Re: Tac-nukes vs. Nuclear Warheads

 

But that offers a pretext for the scene where in order to sneak up on someone you take your interior temperature down to the minimum possible and then go to "silent running" by making your final manuever' date=' and then coast for hours as the ship slowly and steadily heats up until, by the time you are ready to launch your surprise attack, everyone's in their underwear like in that Kraft Dinner ad where the dorks use their dorm radiator to prepare their meal.[/quote']

Go for it. It certainly adds a marvelous "Das Boot" flavor to one's campaign. And campaign flavor is one of the things that keeps your players coming back for more.

 

There are some technical reasons why this might not work in practice, but I'm not going to bother bringing them up since good campaign flavor is such a rare and valuable commodity.

[Captain Obvious]

Re: Tac-nukes vs. Nuclear Warheads

 

There are some technical reasons why this might not work in practice' date=' but I'm not going to bother bringing them up since good campaign flavor is such a rare and valuable commodity.[/quote']

 

"Nearly" wise, my *ss. The man knows the difference between "not correct" and "wrong".

[megaplayboy]

Re: Tac-nukes vs. Nuclear Warheads

 

If detecting a heat signature is based on reading the infrared spectrum(I'm assuming here), then maybe, just maybe, there'd be some future tech breakthrough that would allow one to "cloak" one's heat signature in a manner similar to the "invisibility cloak" being developed by the military and private sector(basically, the surrounding background is projected onto the vehicle or person, so at a distance they're effectively invisible). The "heat cloak" would basically "project" in some manner the surrounding lower thermal signature of empty space, so that the vehicle couldn't be detected thermally at any great distance. A bit far-fetched, yes, but so was the "invisibility cloak" a decade or two ago.

[Outsider]

Re: Tac-nukes vs. Nuclear Warheads

 

As far as thermal cloaking, is it important that you radiate no heat, or is it important that you radiate no heat towards an enemy sensor? Could you, for example, refridgerate your forward hull (the side facing the enemy) such that it blends with the background, and dump the excess heat on the opposite side of the ship?

[Nyrath]

Re: Tac-nukes vs. Nuclear Warheads

 

As far as thermal cloaking' date=' is it important that you radiate no heat, or is it important that you radiate no heat [i']towards an enemy sensor[/i]? Could you, for example, refridgerate your forward hull (the side facing the enemy) such that it blends with the background, and dump the excess heat on the opposite side of the ship?

Again, this isn't the first time this idea has come up. If you want the gritty details, go to

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

and scroll down to the section starting with "Aha!" you say, "why not refrigerate the ship and radiate the heat from the side facing away from the enemy?" and the section below that starts with Dr. John Schilling had some more bad news for would be stealthers trying to radiate the heat from the side facing away from the enemy.

[megaplayboy]

Re: Tac-nukes vs. Nuclear Warheads

 

But if we're talking about em spectrum detection at distance, it's not actual heat being detected, it's the "heat signature"--still seems like it's not an impossible physics problem for future technologists to solve, since it might not necessarily involve diminishing the heat, but rather muting the indications of heat via some means("projecting" a false IR image of reduced heat around the ship, which somehow is of a much greater amplitude than the actual heat signature; shifting the heat into a different spectrum through some sort of energy conversion process; etc.)

[Doc]

Re: Tac-nukes vs. Nuclear Warheads

 

Nope, the physics has already been done on this. Spaceships absent some sort of currently unknown cloaking technology will stand out like little suns in space. If you want to hide, you have to hide behind something.

 

cheers, Mark

 

three caveats: one' date=' obviously, an FTL ship would be completely undetectable on the EM spectrum; two, due to Lorentz contraction, a ship moving at speeds extremely close to lightspeed would appear to be much shorter than it actually was; three, what if the means of propulsion didn't throw out vast amounts of heated gas as fuel, but instead used something like gravity waves(IOW, some kind of gravitic drive, assuming it's feasible in the sci fi setting)--there might still be some means of detecting it, but perhaps not at such great distances.[/quote']

 

Well, that turns out not to be the case.

 

If you are dealing with non-FTL spacecraft, within the limits imposed by the laws of physics, There Ain't No Stealth In Space.

 

The only way to get stealth is by science fictional means. Like FTL or some kind of heat radiator that dumps heat into hyperspace, an alternate dimension, or something like that.

 

well' date=' if your drive doesn't dump heat into space(gravitics or somesuch), and you have a hyperefficient hull that radiates minimal heat(not that implausible, really), and you have a sophisticated imaging technology similar to the "invisibility cloak" that the private sector and military is working on, then you have a minimal heat signature and don't show up on normal visual scanning. All that's required is one technology which is not theoretically possible at the moment but which is not absolutely ruled out, either.[/quote']

 

Well, not quite.

 

[1] Yes, certain types of FTL are undetectable in the EM spectrum. The draw back is that if they are undetectable by any means, there is nothing you can do to prevent the Blortch Empire's war fleet from appearing around your home planet and carpet bombing it into a glassy radioactive sphere. So you need to postulate some way of detecting them.

 

[2] The Lorentz contraction will do little to reduce the heat signature of your spacecraft. However, if your ships are moving relativistically (i.e., near the speed of light), the fact that they are moving almost as fast as the photons of heat revealing their presence will mean that any detectors cannot see where your ships are now, only where they were. The image of the ships will appear to move faster than light due to the optical illusion. This means if the ships are coming down your throat, you will only have a few minutes warning instead of a few days.

 

[3] A gravidic or other drive that has no exhaust plume will still have a thermal signature from the power plant. Accelerating a ship will require X amount of energy, regardless of whether the energy comes from a chemical rocket, a fusion torch, or a gravity drive using electricity from a nuclear reactor. Due to the second law of thermodynamics, there will be some waste heat, and it can be detected. Especially since it will be against the deep space background sky which is at a chilly three degrees Kelvin.

 

Well' date=' it could be like WW2 subs(which surfaced to recharge their batteries and refresh their air); when out of range of enemy detection, safely vent the accumulated heat, then seal up again when going into a combat zone. You could also have a "sponge layer" of interior heat insulation, which has a certain safe tolerance threshold before venting becomes necessary. If the power generator is of a variety to generate minimal waste heat, then it's certainly plausible(to me, anyway) that a ship that doesn't use "torch" propulsion could cruise along for a day or two without baking the crew inside.[/quote']

 

If detecting a heat signature is based on reading the infrared spectrum(I'm assuming here)' date=' then maybe, just maybe, there'd be some future tech breakthrough that would allow one to "cloak" one's heat signature in a manner similar to the "invisibility cloak" being developed by the military and private sector(basically, the surrounding background is projected onto the vehicle or person, so at a distance they're effectively invisible). The "heat cloak" would basically "project" in some manner the surrounding lower thermal signature of empty space, so that the vehicle couldn't be detected thermally at any great distance. A bit far-fetched, yes, but so was the "invisibility cloak" a decade or two ago.[/quote']

 

 

Gee, I've been out for two days, and just look at the length this thread has gone to...

 

Well, anyway, I still think that a spaceship would practicaly be invisible in space. If moving faster than light, the photons carring it's image, heat and radio signatures, etc. will arrive on a planet later than the ship in question, thus making the vessel invisible.

 

Below the speed of light, where photons will carry the ship's images/signatures faster than it's movement, still, it will be very, very dificult to spot that little infra-red spot in the vastness of space. Why keep looking at point 93658363, 78363649, 37485956 instead of any other? Unless there are known military positions there, somewhere else, it is practicaly impossible to detect a ship.

 

A planet could maybe install a Hubble-like detection system covering at once all of space, but, you know...

 

Well, I'm eager to read the answers! Have fun!

[AmadanNaBriona]

Re: Tac-nukes vs. Nuclear Warheads

 

Gee, I've been out for two days, and just look at the length this thread has gone to...

 

Well, anyway, I still think that a spaceship would practicaly be invisible in space. If moving faster than light, the photons carring it's image, heat and radio signatures, etc. will arrive on a planet later than the ship in question, thus making the vessel invisible.

 

Below the speed of light, where photons will carry the ship's images/signatures faster than it's movement, still, it will be very, very dificult to spot that little infra-red spot in the vastness of space. Why keep looking at point 93658363, 78363649, 37485956 instead of any other? Unless there are known military positions there, somewhere else, it is practicaly impossible to detect a ship.

 

A planet could maybe install a Hubble-like detection system covering at once all of space, but, you know...

 

Well, I'm eager to read the answers! Have fun!

 

Well, heck...I'll play Nyraths apprentice here and quote one of my favorite quotes from his site...

Ken Burnside said:

 

Most of the arguments on thermo and space detection run through a predictable course of responses:

1) "Space is dark. You're nuts!"

2) "OK, there's no horizon, but the signatures can't be that bright?"

3) "OK, the drive is that bright, but what if it's off?"

4) "But it's not possible to scan the entire sky quickly!"

5) "OK, so the reactors are that bright, what if you direct them somewhere else..."

6) "What if I build a sunshade?"

7) "OK, so if I can't avoid being detected by thermal output, I'll make decoys..."

8) "Arrgh. You guys suck all the fun out of life! It's a GAME, dammit!"

[megaplayboy]

Re: Tac-nukes vs. Nuclear Warheads

 

One caveat to all the scientific "certainty" about the nature of future space combat: Tsiolkovsky's first major treatise concerning space flight(before which you could probably consider the Dark Ages) was published just over a century ago. We have a very difficult time projecting what will be feasible 100 years from now, or even speculating how new discoveries and theories might affect our assumptions and projections. Certainty in the physical sciences is a very relative thing, no pun intended. We're certain, until something new comes along to knock our old assumptions on their butts.

[Maur]

Re: Tac-nukes vs. Nuclear Warheads

 

I mean that they will have the illusion of traveling faster than light.

 

Interesting article and led me to search for other information and I think I have a better handle on some of it. What one is seeing as moving faster than light is the collection of the frequencies causing a Group Velocity spike to propagate seemingly faster than light while the Phase Velocities of the constituent components is still at or below the speed of light. At least I believe that is what the article you pasted is getting at...

 

That doesn't change the fact that to find the IR signature of a ship coming in with a significant percentage of the speed of light would require one to search in other frequencies for its "Heat" signature due to the doppler shift.

[Beast]

Re: Tac-nukes vs. Nuclear Warheads

 

why not use what the military uses in theory to have secure comms with various systems

Global Hawk and Predator direct their comms away from the enemy instead of using omidirectional antennas towards satalites in space

also incoming commands can only be heard because the antenna only looks at a small patch of sky so jamming is a moot thing

 

I think you have not thought things out fully. If the hull does not radiate any heat' date=' this means that any heat generated inside the hull will stay inside the hull. This includes waste heat from the power plant, drive, and the body heat of all the crew members [i'](if you have been stuck in a closed room with too many people you know what I mean)[/i].

 

So the temperature will eventually rise to a point where the bulkheads will start glowing, all flammable objects will catch fire, and the people will die agonizing deaths.

[Nyrath]

Re: Tac-nukes vs. Nuclear Warheads

 

One caveat to all the scientific "certainty" about the nature of future space combat: Tsiolkovsky's first major treatise concerning space flight(before which you could probably consider the Dark Ages) was published just over a century ago. We have a very difficult time projecting what will be feasible 100 years from now' date=' or even speculating how new discoveries and theories might affect our assumptions and projections. Certainty in the physical sciences is a very relative thing, no pun intended. We're certain, until something new comes along to knock our old assumptions on their butts.[/quote']

Agreed. But that implies that everybody trying to transport Earth analogies into space will have their assumptions knocked on their derrières. Such as people postulating space fighters, like X-Wings or Vipers. Or ships using stealth.

 

*sigh* As you probably figured, this too is on my website. Those who are not yet tired of it can go here

http://www.projectrho.com/rocket/rocket3x.html#aerialbattleship

[Nyrath]

Re: Tac-nukes vs. Nuclear Warheads

 

That doesn't change the fact that to find the IR signature of a ship coming in with a significant percentage of the speed of light would require one to search in other frequencies for its "Heat" signature due to the doppler shift.

Agreed. But this is not particularly difficult.

[Kristopher]

Re: Tac-nukes vs. Nuclear Warheads

 

All you need to hide a ship's waste heat is a way to convert heat directly into another form of energy at 100% efficiency.

 

 

 

 

 

What?

[Inu]

Re: Tac-nukes vs. Nuclear Warheads

 

All you need to hide a ship's waste heat is a way to convert heat directly into another form of energy at 100% efficiency.

 

 

 

 

 

What?

Or to redirect the heat without using any excess energy. You could make a heat laser powered by the waste heat from your engines! Yeah!

[AmadanNaBriona]

Re: Tac-nukes vs. Nuclear Warheads

 

Agreed. But that implies that everybody trying to transport Earth analogies into space will have their assumptions knocked on their derrières. Such as people postulating space fighters, like X-Wings or Vipers. Or ships using stealth.

 

*sigh* As you probably figured, this too is on my website. Those who are not yet tired of it can go here

http://www.projectrho.com/rocket/rocket3x.html#aerialbattleship

 

Man, you have no idea how many hours I've wasted reading your site and following links.....

[Nyrath]

Re: Tac-nukes vs. Nuclear Warheads

 

All you need to hide a ship's waste heat is a way to convert heat directly into another form of energy at 100% efficiency.

 

Yes, it's a pity that the Second Law of Thermodynamics forbids 100% efficiency.

[Doc]

Re: Tac-nukes vs. Nuclear Warheads

 

Well' date=' heck...I'll play Nyraths apprentice here and quote one of my favorite quotes from his site...[/quote']

 

My point is, space is so vast that a new "star" in the sky would probably go unoticed for a long time. A large amount of stars in our galaxy are not visible buy direct observation. We deduce their presence by gravitational effects or other means. A lot of recently discovered dwarf planets were visible on pictures taken decades before their official discovery; nobody had noticed them... So, if a body the size of the moon that's very "near" of us can escape our attention for decades, could we really spot a spaceship, or even an armada coming from, let'say, Sirius A? Even if glowing like a star, it'd just had to stay in a direct line between his home world and its destination to be covered by the luminosity of it's home star. Well, maybe people could notice that this star has become more luminous, though...

 

One caveat to all the scientific "certainty" about the nature of future space combat: Tsiolkovsky's first major treatise concerning space flight(before which you could probably consider the Dark Ages) was published just over a century ago. We have a very difficult time projecting what will be feasible 100 years from now' date=' or even speculating how new discoveries and theories might affect our assumptions and projections. Certainty in the physical sciences is a very relative thing, no pun intended. We're certain, until something new comes along to knock our old assumptions on their butts.[/quote']

 

So very true...

 

By the way, Nyrath, I liked very much the french touch "on their derrières"!

 

Agreed. But this is not particularly difficult.

 

True, in fact, we already do this to caracterise stars that are moving away from us.

 

 

All you need to hide a ship's waste heat is a way to convert heat directly into another form of energy at 100% efficiency.

 

What?

 

Yes' date=' it's a pity that the Second Law of Thermodynamics forbids 100% efficiency.

 

Moreover, you still would have to "vent" it in some way, thus making the ship "visible" by some mean.

 

 

It's always a pleasure to discuss here with you, gentlemen. Have fun:rockon:!

[AmadanNaBriona]

Re: Tac-nukes vs. Nuclear Warheads

 

My point is, space is so vast that a new "star" in the sky would probably go unoticed for a long time. A large amount of stars in our galaxy are not visible buy direct observation. We deduce their presence by gravitational effects or other means. A lot of recently discovered dwarf planets were visible on pictures taken decades before their official discovery; nobody had noticed them... So, if a body the size of the moon that's very "near" of us can escape our attention for decades, could we really spot a spaceship, or even an armada coming from, let'say, Sirius A? Even if glowing like a star, it'd just had to stay in a direct line between his home world and its destination to be covered by the luminosity of it's home star. Well, maybe people could notice that this star has become more luminous, though...

Right now we'd be sitting ducks. No arguments there.

 

however, right now with current imaging tech we "could" still detect such thermal signatures if we were bothering to look, if I understand correctly.

 

Heck, wasn't it one of the folk at SETI that just figured out how to gang 8 PS3's together to do the work of a Cray so they can keep the skyscans going without having to rent supercomputer time?

 

Nyrath? Link?

 

(Dad was part of the Hubble team, FWIW)

[Nyrath]

Re: Tac-nukes vs. Nuclear Warheads

 

however, right now with current imaging tech we "could" still detect such thermal signatures if we were bothering to look, if I understand correctly.

Nyrath? Link?

 

Your wish is my command.

 

From http://www.projectrho.com/rocket/rocket3w.html#scan

 

Executive summary: Off the shelf hardware can do a full sky scan in about 4 hours. Hardware about 8 to 10 years in the future could do full sky scan and compare with the prior scan, in a package that was milspec and rad-hardened. Therefore it will be a trivial task for hardware that is 50 to 100 years in the future.

 

Ken Burnside said:

 

A full spherical sky search is 41,000 square degrees. A wide angle lens will cover about 100 square degrees (a typical SLR personal camera is about 1 square degree); you'll want overlap, so call it 480 exposures for a full sky search, with each exposure taking about 350 megapixels.

 

Estimated exposure time is about 30 seconds per 100 square degrees of sky looking for a magnitude 12 object (which is roughly what the drive I spec'd out earlier would be). So, 480 / 2 is 240 minutes, or about 4 HOURS for a complete sky survey. This will require signal processing of about 150 gigapizels per two hours, and take a terabyte of storage per sweep.

 

That sounds like a lot, but...

 

Assuming 1280x1024 resolution, playing an MMO at 60 frames per second...78,643,200 = 78 megapixels per second. Multiply by 14400 seconds for 4 hours, and you're in the realm of 1 terapixel per sky sweep Now, digital image comparison is in some ways harder, some ways easier than a 3-D gaming environment. We'll say it's about 8x as difficult - that means playing World of Warcraft on a gaming system for four hours is about comparable to 75 gigapixels of full sky search. So not quite current hardware, but probably a computer generation (2 years) away. Making it radiation hardened to work in space, and built to government procurement specs, maybe 8-10 years away.

 

I can buy terabyte hard drive arrays now.

 

I can reduce scan time by adding more sensors, but my choke point becomes data processing. On the other hand, it's not unreasonable to assume that the data processing equipment will get significantly better at about the same rate that gaming PCs get significantly better.

[AmadanNaBriona]

Re: Tac-nukes vs. Nuclear Warheads

 

Your wish is my command.

 

From http://www.projectrho.com/rocket/rocket3w.html#scan

 

Executive summary: Off the shelf hardware can do a full sky scan in about 4 hours. Hardware about 8 to 10 years in the future could do full sky scan and compare with the prior scan, in a package that was milspec and rad-hardened. Therefore it will be a trivial task for hardware that is 50 to 100 years in the future.

 

Danke