On the radiation of heat in space

[Coalition]

Yes. The warship is basically a giant spinning saucer (not for gravity, but to reduce predictable exposed face), usually with one main cannon (sometimes two or mounted on a sort of turret) and is designed to engage at vast distances.

One solution with lasers, is to mount two emitters on it, one 'dorsal' and one 'ventral'. While the dorsal mount is lasing one target, the ventral is hunting for another. When it finds a target, and the dorsal is finished, the laser is directed through the ventral mount. Of course, you could always have more lasers, and internal mirrors diverting the beam around as necessary.

How big do you plan on your ships getting? If circular, and large enough, would the ring serve as a form of particle accelerator? (I know, it will require a large ring, and sending particles out will cause the ship to rotate in the other direction)

Assaults are actually rather difficult in this scenario, as the planetoid is basically a giant heat sink. This gets worse and worse for the energy expended up until you point your Dyson Swarm at the offending world, and if your enemy has reached that point it will likely just piss them off. R-bombs have a speed limit and the energy required to make them work can also be used to move planets defensively.

Well, the best way to deal with relatively stationary orbital bases would be lnog-range attacks taking into advantage the lack of maneuverability. Your ship's combat acceleration allows you to dodge much better than the enemy base can, so its effective combat range is shorter. Of course, the ability to mount huge weapons, and the entire rock as a heat sump will be useful.

[The Duchess of Zeon]

For my TGG stories, the Taloran Star Empire uses a energy-sink cloaking device. Basically, they have extensive internal energy sinks they can shove the vast majority of their normal energy emissions into, effectively rendering the ship invinsible to passive sensors until the sink is full. Then they dump it in one burst--which is intense enough that it would, of course, blind sensors which are highly focused in looking for a very, very small energy signature--allowing them to shift position on thrusters while the enemy sensors are blinded and then resume the energy-cloak regime.

I thought it was a much more realistic attempt at a spaceborne stealth regime than the Star Trek style technomagic, at least.

[Ariphaos]

One solution with lasers, is to mount two emitters on it, one 'dorsal' and one 'ventral'. While the dorsal mount is lasing one target, the ventral is hunting for another. When it finds a target, and the dorsal is finished, the laser is directed through the ventral mount. Of course, you could always have more lasers, and internal mirrors diverting the beam around as necessary.

That wasn't the reason for the turret. The turret exists so that the laser (or whatever weapon) can be focussed onto the same point of a likely spinning target. I use plasma-trap shields as a counter to lasers, however (fluoresce when struck, causing part of the energy to dissipate when it hits the vessel). On occasion special ablative plate is used too, or instead of the 'shields'.

How big do you plan on your ships getting? If circular, and large enough, would the ring serve as a form of particle accelerator? (I know, it will require a large ring, and sending particles out will cause the ship to rotate in the other direction)

Pre-magitech, several hundred meters. I imagine such vessels could easily scale into the multi-kilometer range for light-hour and light-day vessels. Particle accelerators are normally intensely wasteful, though some of the magitech in my setting is based on the use of Yevatron-style accelerators, some of which are on 'ships'.

Well, the best way to deal with relatively stationary orbital bases would be lnog-range attacks taking into advantage the lack of maneuverability. Your ship's combat acceleration allows you to dodge much better than the enemy base can, so its effective combat range is shorter. Of course, the ability to mount huge weapons, and the entire rock as a heat sump will be useful.

When you fire a projectile, laser or whatever, you produce a certain amount of heat which you must dispose of. On a ship, this means you don't want to fire too early - even a space station may be capable of accelerations that will throw of attacks from light-hours away. This is especially true if they have additional defenses against lasers.

A space station, especially one with readily available supplies, doesn't have to worry about overheating nearly as much. It's going to be able to afford to make a bigger cloud than you. It can vent more than you, and has better logistical support than you - it can literally toss out hot rocks and bring in cold ones.

For my TGG stories, the Taloran Star Empire uses a energy-sink cloaking device. Basically, they have extensive internal energy sinks they can shove the vast majority of their normal energy emissions into, effectively rendering the ship invinsible to passive sensors until the sink is full. Then they dump it in one burst--which is intense enough that it would, of course, blind sensors which are highly focused in looking for a very, very small energy signature--allowing them to shift position on thrusters while the enemy sensors are blinded and then resume the energy-cloak regime.

Problems I had with this idea:
1: The WMAP survey measured in microKelvins. That's just insane - an internal cloak like you're talking about is likely only going to work against a technologically inferior opponent. A directional cloak might fare better, but I'd be skeptical. Flying ice cream cones!
2: "Dumping it all at once" sounds a lot easier than it is, and for the tonnes of effort you expend in doing that, grams are spent on the counter - arrays of backup sensors and more tolerant sensors. Directional cloaking doesn't have this problem, of course.

[Ford Prefect]

How big do you plan on your ships getting?

It would probably top out at about eight hundred metres for the richest human polities. Spaceships, in particular warships, tend to be staggeringly expensive. This is in part due to sophistication, as a warship tends to be the most visible expression of a polity's technological, economic and even cultural advancement.

Yes. The warship is basically a giant spinning saucer (not for gravity, but to reduce predictable exposed face), usually with one main cannon (sometimes two or mounted on a sort of turret) and is designed to engage at vast distances.

That's an interesting design choice. I'm biased towards the more traditional 'long' style design, however.

This begins to happen with realistic ship accelerations at about a light-minute. At accelerations of around 10% of c per second you can have relativistic dogfights in space.

Of course would that be something like pulling three million gees? That might be just a wee bit out of what I was planning to do. Just a wee bit.

I thought it was a much more realistic attempt at a spaceborne stealth regime than the Star Trek style technomagic, at least.

The idea appears conceptually similar to 'thermo-optical' cloaking devices that occasionally pop up in literature and television. Frankly, until I decide I want some funky Alastair Reynolds styled technolgy floating about, that sort of stealth would be hard to manage. Even for something as small an armoured battlesuit.

[Darth Wong]

For my TGG stories, the Taloran Star Empire uses a energy-sink cloaking device. Basically, they have extensive internal energy sinks they can shove the vast majority of their normal energy emissions into, effectively rendering the ship invinsible to passive sensors until the sink is full. Then they dump it in one burst--which is intense enough that it would, of course, blind sensors which are highly focused in looking for a very, very small energy signature--allowing them to shift position on thrusters while the enemy sensors are blinded and then resume the energy-cloak regime.

I thought it was a much more realistic attempt at a spaceborne stealth regime than the Star Trek style technomagic, at least.

Interesting idea but I don't see why the sensor-blinding effect would last for any significant length of time. Electronic sensors aren't like human eyes, and unless the sensor is actually damaged by the burst (rather unlikely unless you're so close to the vessel that you can use the burst as a weapon), then it will just hit maximum level until the burst is over, and continue functioning normally.

Normally, sensor-blinding is something that's caused by a constant effect, ie- you can blind IR sensors by getting them to point at the Sun. A burst won't have much effect on sensors except to give everyone a fix on your current location.

For sci-fi stealth, a better approach would be to have directional radiators. In space, you cannot detect even an enormous amount of radiation as long as it's directed away from you. In atmosphere, this wouldn't work as well because the radiation will tend to heat up the air.

[Ariphaos]

That's an interesting design choice. I'm biased towards the more traditional 'long' style design, however. :)

Overheats, though I use those for coilgun-launched ships, of course. Really, it's the only way for 'regular' STL interstellar travel. I've actually been tempted to build a galactic-scale setting that -does- use that. People with extended lifespans make million-year pilgrimages to Earth, etc.

A not so modest propulsion system at insane efficiencies still ends up requiring square kilometers of dissipation surface for a large vessel. You can get thinner by adding more fins, but this adds weight - your longship will be less maneuverable than my saucer for the same amount of heat dissipation. All other things equal, in war, I win.

Of course would that be something like pulling three million gees? That might be just a wee bit out of what I was planning to do. Just a wee bit.

I imagine it's outside of what most people want to do.

The idea appears conceptually similar to 'thermo-optical' cloaking devices that occasionally pop up in literature and television. Frankly, until I decide I want some funky Alastair Reynolds styled technolgy floating about, that sort of stealth would be hard to manage. Even for something as small an armoured battlesuit.

Things are different inside an atmosphere, possibly even in a dense enough (say, pre-protostar) nebula, where certain wavelengths are scattered and obscured. You can also do tricks like flying out of a star, and so on - bandits have a problem wherein by necessity they will not have vast arrays of sensors, for example, so such tricks will not be entirely absent from a setting.

[Ford Prefect]

Overheats, though I use those for coilgun-launched ships, of course. Really, it's the only way for 'regular' STL interstellar travel.

Luckily for me then, that there would be practically no one who would want to go slower-than-light between stars.

I've actually been tempted to build a galactic-scale setting that -does- use that. People with extended lifespans make million-year pilgrimages to Earth, etc.

That's a particularly interesting idea.

I imagine it's outside of what most people want to do.

I decided that this time I wanted to have a 'reasonable' level of technology, thus the crew would be killed at anything above some tens of gravities.

You can also do tricks like flying out of a star, and so on - bandits have a problem wherein by necessity they will not have vast arrays of sensors, for example, so such tricks will not be entirely absent from a setting.

Of course, in my mind piracy in space would be so expensive that the only way to really break even is to somehow hit a polity's merchant spacy, which would not be advisable. They'd probably just be better off doing their own mining and selling it.

[The Duchess of Zeon]

Interesting idea but I don't see why the sensor-blinding effect would last for any significant length of time. Electronic sensors aren't like human eyes, and unless the sensor is actually damaged by the burst (rather unlikely unless you're so close to the vessel that you can use the burst as a weapon), then it will just hit maximum level until the burst is over, and continue functioning normally.

Normally, sensor-blinding is something that's caused by a constant effect, ie- you can blind IR sensors by getting them to point at the Sun. A burst won't have much effect on sensors except to give everyone a fix on your current location.

For sci-fi stealth, a better approach would be to have directional radiators. In space, you cannot detect even an enormous amount of radiation as long as it's directed away from you. In atmosphere, this wouldn't work as well because the radiation will tend to heat up the air.

Thanks for the commentary on it. It's heartening to know I was on to something.

Of course, it has the secondary advantage that "Dump the sink!" is an actual order in combat.

[Ender]

It would be interesting to see a sci-fi story where the ship is not armoured at all. The whole idea of armour plate on starships implies that mass is not an issue at all, and that's really one of the most absurd (albeit common) conventions in sci-fi. Hell, the lunar lander had fucking foil between the astronauts and the vacuum.

You may wish to check out the Revelation Space series by Alistair Reynolds then, he just has them using a couple of meters of ice that works as armor, but is really just there to protect the ship from collisions as it flies.

For soft sci-fi there is always the Star Wars option; neutrino radiators. Can be embedded in the hull and from the geometry apparently emit large amounts of neutrinos without absorbing them (at least, not any more than normal matter does).

There is the fact that they will kill the crew though (at least when dealing with the type of power you get in most scifi series)

[Gil Hamilton]

You may wish to check out the Revelation Space series by Alistair Reynolds then, he just has them using a couple of meters of ice that works as armor, but is really just there to protect the ship from collisions as it flies.

That's better in deep space, but you'll have a problem that locally the ice is going to sublime off in direct sunlight in a reasonably expedience fashion unless you find some way to replenish your ice shield or mix the ice with something that will prevent it from boiling off as easily.

For my TGG stories, the Taloran Star Empire uses a energy-sink cloaking device. Basically, they have extensive internal energy sinks they can shove the vast majority of their normal energy emissions into, effectively rendering the ship invinsible to passive sensors until the sink is full. Then they dump it in one burst--which is intense enough that it would, of course, blind sensors which are highly focused in looking for a very, very small energy signature--allowing them to shift position on thrusters while the enemy sensors are blinded and then resume the energy-cloak regime.

I thought it was a much more realistic attempt at a spaceborne stealth regime than the Star Trek style technomagic, at least.

Well, it is kind of technomagic. Just a different kind of technomagic, since I imagine it involves a heat reservoir of righteously absurd properties to store alot of energy as heat and prevent it from cooking the inside of your ship.

Also, you'll have to consider that there will be one emission source that which you'll definitely be fighting a losing battle by trying to shield (aside from your exhaust if you try to move while the system is running) and that is the power source needed to shunt heat to the high energy reservoir. Remember, the heat sink where you are storing all that energy is almost certainly going to be hotter than the systems that you are cooling and disguising the emissions of. Thus, you must do work to in order to add heat to that reservoir or else the God of Thermodynamic smacks you on the nose with a newspaper (keep in mind that I'm envisioning your system to be a glorified refrigerator).

Besides, any space born ship is going to have deployable sensor booms which they can retract in high radiation environments, you know? If you burn out the cameras on one face of the ship by venting whatever magic fluid you were storing all that heat in at them, what stops them from deploying their back ups or just rolling the ship to point cameras on another face?

[Ariphaos]

There is the fact that they will kill the crew though (at least when dealing with the type of power you get in most scifi series)

*blinks* wha? A ten-kilometer-radius ship made of solid lead is not going to absorb a trillionth of the neutrino energy emitted if the dissipater is at the center of the vessel - what are you talking about?

[Ender]

There is the fact that they will kill the crew though (at least when dealing with the type of power you get in most scifi series)

*blinks* wha? A ten-kilometer-radius ship made of solid lead is not going to absorb a trillionth of the neutrino energy emitted if the dissipater is at the center of the vessel - what are you talking about?

I'm talking about the results when you run the numbers, what do you think I'm talking about? Individually, the absorption rate of neutrinos is laughable. But when you are talking about releasing stellar scale energies as neutrinos you deliver sufficient radiation poisoning to kill the crew. Do the math and you'll see. In SW the shields block neutrinos, but otherwise you are SOL.

[Ender]

We already have that with fighter planes in real-life, assuming you're talking about sci-fi space combat. There's really no reason you have to show ships being able to absorb punishment rather than trying to evade or intercept it.

Well, that really depends onth weaponry being used, doesn't it? If the enemy is using lasers, you won't know to dodge until you get hit. Same applies for high relativistic attacks. No need to dodge a missle when you can just shoot it down. Really, in any kind of realistic situation dodging simply won't be practical.

[Ariphaos]

I'm talking about the results when you run the numbers, what do you think I'm talking about? Individually, the absorption rate of neutrinos is laughable. But when you are talking about releasing stellar scale energies as neutrinos you deliver sufficient radiation poisoning to kill the crew. Do the math and you'll see. In SW the shields block neutrinos, but otherwise you are SOL.

When a giant star goes supernova, 1% of the neutrino energy gets absorbed. For an eight-plus solar-mass star. I'm still honestly not sure what you're talking about. Especially considering such a device would likely be able to control neutrino energy.

Well, that really depends onth weaponry being used, doesn't it? If the enemy is using lasers, you won't know to dodge until you get hit. Same applies for high relativistic attacks. No need to dodge a missle when you can just shoot it down. Really, in any kind of realistic situation dodging simply won't be practical.

There's the 'duh' answer.

When near hostiles, dodge. Always.

[The Duchess of Zeon]

Well, it is kind of technomagic. Just a different kind of technomagic, since I imagine it involves a heat reservoir of righteously absurd properties to store alot of energy as heat and prevent it from cooking the inside of your ship.

Also, you'll have to consider that there will be one emission source that which you'll definitely be fighting a losing battle by trying to shield (aside from your exhaust if you try to move while the system is running) and that is the power source needed to shunt heat to the high energy reservoir. Remember, the heat sink where you are storing all that energy is almost certainly going to be hotter than the systems that you are cooling and disguising the emissions of. Thus, you must do work to in order to add heat to that reservoir or else the God of Thermodynamic smacks you on the nose with a newspaper (keep in mind that I'm envisioning your system to be a glorified refrigerator).

Besides, any space born ship is going to have deployable sensor booms which they can retract in high radiation environments, you know? If you burn out the cameras on one face of the ship by venting whatever magic fluid you were storing all that heat in at them, what stops them from deploying their back ups or just rolling the ship to point cameras on another face?

Well, of course, but by that time the ship will have shifted position and reactivated the sink.

Probably the best response will be to lay down a spread of flak-bursts and missiles with timed fusings in the general vicinity, which could be at least localized.

But that at least makes the ship as stealthy as a submarine, and you can ride out near misses, while waiting tensely and praying that you don't get smacked with a lucky direct hit.

[Gil Hamilton]

I still think that would be hard. Rolling a ship or receiving firing data from other ship that didn't have its sensors burnt out isn't going to take a huge amount of time and the drive system for you ship is going to be venting a fair bit of exhaust that will point to you like and arrow. I'd think you'd have to be quite close to the other ship to fry a face of sensors anyway. If it were merely very very bright, as Darth Wong has noted, it wouldn't actually destroy the sensor but hit its max light register and in a bad situation help the other guys targeting systems if they were aiming for emission.

Though granted that takes something away from the submarine aspect of it.

[Ford Prefect]

When a giant star goes supernova, 1% of the neutrino energy gets absorbed. For an eight-plus solar-mass star. I'm still honestly not sure what you're talking about. Especially considering such a device would likely be able to control neutrino energy.

I think the difference here is that a neutrino radiator is designed to convert all heat into neutrinos (this has always struck me as being patently ludicrous). In higher end universes, with near stellar power outputs, this results in a large number of neutrinos.

For this universe I've been considering, the only thing with stellar power outputs are stellar objects (and those mysterious Clarketech AIs in the dark of space *ghostly noises*). The amount of neutrinos wouldn't be nearly as high.

[Darth Wong]

We already have that with fighter planes in real-life, assuming you're talking about sci-fi space combat. There's really no reason you have to show ships being able to absorb punishment rather than trying to evade or intercept it.

Well, that really depends onth weaponry being used, doesn't it? If the enemy is using lasers, you won't know to dodge until you get hit. Same applies for high relativistic attacks. No need to dodge a missle when you can just shoot it down. Really, in any kind of realistic situation dodging simply won't be practical.

I meant "evade" as in "make evasive maneuvers so that it is difficult to predict your flight path and hit your ship", not "evade a particular shot by seeing it and then reacting by moving out of the way". Also remember that in a hypothetical situation where unarmoured ships fight with lasers, they would probably fight at very long range, rather than getting into the kind of spitting-range slugfests we're used to seeing in most television and movie sci-fi. At those kinds of ranges, you're also relying on enemy inaccuracy.

[Ariphaos]

I still think that would be hard. Rolling a ship or receiving firing data from other ship that didn't have its sensors burnt out isn't going to take a huge amount of time and the drive system for you ship is going to be venting a fair bit of exhaust that will point to you like and arrow. I'd think you'd have to be quite close to the other ship to fry a face of sensors anyway. If it were merely very very bright, as Darth Wong has noted, it wouldn't actually destroy the sensor but hit its max light register and in a bad situation help the other guys targeting systems if they were aiming for emission.

The problem is they basically recover by discharging a la a capacitor... milliseconds, if that. These are also likely tiny, highly directional devices and after you've made your light burst, you are already visible to other sensors on the ship.

I think the difference here is that a neutrino radiator is designed to convert all heat into neutrinos (this has always struck me as being patently ludicrous). In higher end universes, with near stellar power outputs, this results in a large number of neutrinos.

That's all well and good - but he seemed to be arguing the general case. Even the -stellar- case is suspect. A significant percentage of fusion power is already lost to neutrinos (on the order of a few percent or so), so that means, on Earth, we are still receiving a notable amount of wattage from neutrinos per square meter, from our own Sun. Not only that, but if you are capable of doing this, you are naturally going to want to use low-energy neutrino emissions!

10^11 neutrinos per square centimeter per second * .8 MeV (can also be .4 MeV, possibly even lower) = 1.2 kilowatts per square meter. You need to get into the GeV range before neutrinos start interacting. Meaningful interactions require high-energy neutrinos - the Earth is actually opaque to PeV neutrinos. Keep them low energy (as is likely) and you're fine.

If they were all low-energy neutrinos, you could multiply that by a billion and you wouldn't notice.

[Ender]

I'm talking about the results when you run the numbers, what do you think I'm talking about? Individually, the absorption rate of neutrinos is laughable. But when you are talking about releasing stellar scale energies as neutrinos you deliver sufficient radiation poisoning to kill the crew. Do the math and you'll see. In SW the shields block neutrinos, but otherwise you are SOL.

When a giant star goes supernova, 1% of the neutrino energy gets absorbed. For an eight-plus solar-mass star.

Yes. 10^45 joules of energy over a distance of multiple AU. Yet you find my statement that people will get >1000 rads at <1 km hard to swallow. This is because you are going by your gut feeling instead of the math.

I'm still honestly not sure what you're talking about.

That would be because you are too fucking lazy to do the math. There is an old engineering quote "A statement without math is at best an opinion". Mad, Connor, and I did the math for this a while back. From a 10^25 watt source, from 1-100 meters you are looking at between 1000 - 600 rads depending on distance and profile. This is sufficient to kill you damn near instantly. This continues to drop off until you are about 20 km away from the point source, at which point it becomes safe. The intervening distance is about the equivlent of bathing in reactor coolant and will kill you over a couple of minutes depending on a couple of factors, such as how much of the energy is tau and nuon neutrinos and their individual energy. I don't know of too many ships that mount their radiators 20 km away from the habitable zones, do you?

Especially considering such a device would likely be able to control neutrino energy.

Well there's a leap in logic. So being able to duplicate an observed natural process instantly translates into complete control over the gravitational and strong nuclear force despite the fact that they are totally unrealted? Drop the desperate handwavng. Not to mention that even if you could make a neutrino laser it would be useless because pair production and conservation of momentum means that you would shoot he beam straight back into the ship? And your plan to improve a waste heat disposal unit is the increase the waste heat load by adding more processes to it - FUCKING GENIUS. For your next trick are you going to smack yourself in the head with a hammer?

There's the 'duh' answer.

Blow it out your ass. You lost the right to be condescending when you decided you couldn't be bothered to do the math above.

When near hostiles, dodge. Always.

And thus burn precious delta V while at the same point showing them exactly where you are going and giving them a nice big thermal plume to target. Brilliant fucking plan. Try, when hostiles are near, fire the cold gas thrusters and start spinning on your long axis. That conserves the delta V until you have to run, makes you harder to target, and doesn't tell them your destination.

[Darth Wong]

Obviously, stellar-level energies are unsustainable without some kind of exotic means of achieving ultra-high efficiency and directionally dumping whatever waste heat is produced. Mind you, the very idea of dumping waste heat through a neutrino radiator inherently assumes such exotic technology anyway; you can't arbitrarily take waste heat and convert it into another form (never mind a drastically different one, like a neutrino stream) without the conversion process itself producing waste heat, also impossible to deal with when producing stellar level energies.

[Ariphaos]

Yes. 10^45 joules of energy over a distance of multiple AU. Yet you find my statement that people will get >1000 rads at <1 km hard to swallow. This is because you are going by your gut feeling instead of the math.

I'm still honestly not sure what you're talking about.

That would be because you are too fucking lazy to do the math. There is an old engineering quote "A statement without math is at best an opinion". Mad, Connor, and I did the math for this a while back. From a 10^25 watt source, from 1-100 meters you are looking at between 1000 - 600 rads depending on distance and profile. This is sufficient to kill you damn near instantly. This continues to drop off until you are about 20 km away from the point source, at which point it becomes safe. The intervening distance is about the equivlent of bathing in reactor coolant and will kill you over a couple of minutes depending on a couple of factors.

You've been making the statements, show the math. In particular, break it down for the PPII reaction at ~.86 MeV since that would seem to be the reasonable energy profile if we're 'mimicking a natural source' - as the most common one.

Well there's a leap in logic. So being able to duplicate an observed natural process instantly translates into complete control over the gravitational and strong nuclear force despite the fact that they are totally unrealted? Drop the desperate handwaving.

More to the point, it would mimic a specific subset of natural processes. Why would you mimic the GeV-PeV neutrino generation that causes these radiation events? Why would you even assume that they are going to occur?

I have no means of working the math for sub-MeV neutrinos, because they are physically incapable of making anything larger than an electron (511 KeV, and many of them can't even do that. If you do, and you can show me why the most common, and likely, type of neutrinos would cause such reactions, I will happily concede.

If you can't, or go by 'well Super-K detects one in a billion neutrinos' - most of which are in the GeV range - or start from any ignorant point like that, then you are just spouting opinion.

Blow it out your ass. You lost the right to be condescending when you decided you couldn't be bothered to do the math above.

Says the hypocrite who talks about 'doing the math' but won't show exactly how.

I am, of course, assuming an engagement scenario. However-

And thus burn precious delta V while at the same point showing them exactly where you are going and giving them a nice big thermal plume to target.

Irrelevant. If you are observed in space, your trajectory is already known. You can't hide in deep space. WMAP, now, measures in the microKelvin range. Now. As in today. Angular resolution is crap, yes. But, put simply, your ship is emitting blackbody radiation, across a wide variety of wavelengths. Unless you have an -incredible- technological advantage over your opponent, you are going to be seen.

Brilliant fucking plan. Try, when hostiles are near, fire the cold gas thrusters and start spinning on your long axis.

At best, this is going to mimic the directional cloak Wong and I have both already mentioned, but in order to do so, that will require a lot of very tightly controlled gas.

That conserves the delta V until you have to run, makes you harder to target, and doesn't tell them your destination.

If it can hide you, you are wrong on the first point. If it can't hide you, you are wrong on the second point. In both cases, you are wrong on the third point.

On the other hand, at a distance of one light-hour, and a random acceleration of .000001 m/s (one um/sec - REALLY burning that Delta V, aren't we!), if your ship has a face less than 25 meters in diameter, it is impossible for a single shot to make a guaranteed hit against you, because the uncertainty of your position is nearly 26 meters.

[Ariphaos]

Haven't gotten sleep and this irked me, so I decided to do Ender's math for him and see what I could come up with, despite being asked to prove a negative.

From here we have the 12.5 million-gallon, 50-kilotonne super-K data. Basically it boils down to slightly less than 15 neutrino detections per day, not all of which were real or solar. It should be noted that its resolution was down to 5 MeV, but many detections were still in the GeV range - so a lot of these are very high energy.

70 billion solar neutrinos pass through every square centimeter of the Earth every second. This works out to 60,480,000,000,000,000,000 per day per square meter. Since super-K is cylindrical, the smallest face it had would be its top/bottom as circles of 39.3 meters in diameter, or 1,210 square meters, for a total of:

73,180,800,000,000,000,000,000 neutrinos per day (or more) passing through the detector, for a detection rate of one per 4,878,720,000,000,000,000,000, or less.

Now, since that's over such a vast volume, it doesn't represent a human very well. But, humans, being ugly bags of mostly water, will not have a significantly different absorption profile, so, the events per gallon are one 12.5-millionth less, or about one event per 6e28 neutrinos, per gallon, or four kilograms (roughly). Per kilogram (to calculate radiation) it's then one per 2.4e29.

I don't have very good data on the spread of detected neutrinos, but if we go by the assumption that all intercepted neutrinos are a thousand times more powerful than those that aren't (likely way too high), the kilogram of flesh is then absorbing 1/2.4e26 of the neutrino energy passing through it, as radiation. For a solar grade output of 4e26W, that's about an eighth of a Sievert (~13 REMs) per second at a distance of one meter. Lethal, eventually, so close, with a high value for 'stellar', a high proportion of high-energy neutrinos, but certainly not instantly. At a kilometer (this is a star ship in a very literal sense of the word after all), counting a red dwarf as 'stellar', lower-energy neutrinos, or a high-grade of efficiency. Combine two or more of those factors and it quickly becomes an utter non-issue.

[Ariphaos]

Ghetto edit, should be:
"At a kilometer (this is a star ship in a very literal sense of the word after all), counting a red dwarf as 'stellar', lower-energy neutrinos, or a high-grade of efficiency, this is quite tolerable."

[Darth Wong]

Ghetto edit, should be:
"At a kilometer (this is a star ship in a very literal sense of the word after all), counting a red dwarf as 'stellar', lower-energy neutrinos, or a high-grade of efficiency, this is quite tolerable."

The waste heat produced by the heat exchange unit for the neutrino converter would be a much more serious threat than the neutrinos anyway. Efficiency is obviously not near-perfect if you need such powerful heat dissipation devices in the first place, yet it needs to be near-perfect for the conversion and collection of this waste heat. It's still hand-wavium to a certain extent, although at least you can say the math works out, if not the feasibility.