Hard Light Productions Forums
General FreeSpace => FreeSpace Discussion => Topic started by: blowfish on August 31, 2009, 08:45:03 pm
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You're trying to apply logical spaceship design to Freespace
DOES NOT COMPUTE
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;-)
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You're trying to apply logical spaceship design to Freespace
DOES NOT COMPUTE
I think the same can be said for most soft sci-fi ship designs. The nipple-on-a-boob bridge of the Enterprise, the huge blind spots on Minbari ships, the gaping holes in Star Wars' rebel transports, and every single feature of the Space Battleship Yamato and SDF-1 Macross ("even our capship turns into a giant robot!"). Rule of Cool wins the day. This model rocks.
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Who sais they are still using glass in that time. Maybe they found some transperent material that's just as tough as the rest of the hullarmor, but is only used sparingly because it's hard to get.
In that case a big cockpit would be an advantage, because the pilot would have a better viewing angle.
Granted, that might not such a bit matter for a bomber, but for a fighter like the Ulysses (good example since the Ulysses' cockpit makes up about one third of the whole fighter) that is important.
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You're trying to apply logical spaceship design to Freespace
DOES NOT COMPUTE
Plus: A logical spacefighter a few centuries ahead will most probably have no pilot at all.
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Heck, we've already got the Predator UAV...
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On the contrary, a good many FS ships have some semblance of reason to them. You could argue that the Apollo is balanced along its CG: the main engines are just higher than the CG while the smaller, less powerful secondaries are located further down, cancelling the moment. The original Herc is fairly reasonable... and you could make an argument for the Herc 2 if you "put your back into it." The Erinyes is actually quite logical in its general configuration as well.
...About the cockpit sticking out... A cockpit is a weak point on any space ship or aircraft. Just as the case is that your head needs to stick out to do its job, so does the cockpit. In my opinion, Vasudan pilots are actually better protected than their Terran contemporaries in most circumstances (as far as the cockpit goes). Of course, they're not going to see outside of forward too well...
-Thaeris
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No, no, no. A thousand times no. No 'space fighter' (if such absurdities ever existed; I can reference some great pages on space warfare that show why they really won't) would be built with a single set of huge engines at the back and a 'pointy', aerodynamic shape. There's just no logic to it.
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The most logical spacefigther I have seen so far is the Aurora Starfury from Babylon 5.
For those who don't know it, it has gib engines to the front and back and small manouvering thrusters up, down, left and right.
The pilot sits in the center of the turning axis to minimize the effects of g-forces during turns.
And the entire cockpit is in fact an escape-pod that can be ejected from the rest of the fighter.
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No, no, no. A thousand times no. No 'space fighter' (if such absurdities ever existed; I can reference some great pages on space warfare that show why they really won't) would be built with a single set of huge engines at the back and a 'pointy', aerodynamic shape. There's just no logic to it.
actually if you are building a craft that needs to be effective in both space and within an atmosphere or dense nebula aerodynamic shapes make a lot of sense and most of the popular sci-fi assume that space fighters will do both. the most obvious contrast is in star wars between RA/NR/GA designs such as X-Wing, A-Wing, B-Wing etc and TIEs of most designs and that is that because of the solar panels on TIES they only pitch well in anything other than vacuum but in space their agility is brilliant. I know this is an extreme example but I think serves as an example of space based design Vs atmospheric design
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The most logical spacefigther I have seen so far is the Aurora Starfury from Babylon 5.
For those who don't know it, it has gib engines to the front and back and small manouvering thrusters up, down, left and right.
The pilot sits in the center of the turning axis to minimize the effects of g-forces during turns.
And the entire cockpit is in fact an escape-pod that can be ejected from the rest of the fighter.
The Starfury pilot stands instead of sits.
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No, no, no. A thousand times no. No 'space fighter' (if such absurdities ever existed; I can reference some great pages on space warfare that show why they really won't) would be built with a single set of huge engines at the back and a 'pointy', aerodynamic shape. There's just no logic to it.
actually if you are building a craft that needs to be effective in both space and within an atmosphere or dense nebula aerodynamic shapes make a lot of sense and most of the popular sci-fi assume that space fighters will do both. the most obvious contrast is in star wars between RA/NR/GA designs such as X-Wing, A-Wing, B-Wing etc and TIEs of most designs and that is that because of the solar panels on TIES they only pitch well in anything other than vacuum but in space their agility is brilliant. I know this is an extreme example but I think serves as an example of space based design Vs atmospheric design
TIE fighters make no sense as a space design. Moreover all the 'aerodynamic' designs are so cripplingly stupid as spacecraft that they wouldn't ever fly. The Shuttle is already hobbled by its need to be aerodynamic; a fighter certainly wouldn't be able to afford that baggage.
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In real space design don't count much. Counts only where is placed centre of the mass, thrusters and if it is some kind of battleships "stealth" ability (sphere is good) and turrets mounted in good places. Soo... you can get anything you want even Tie Fighter which from sides is just like sting duck :P
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TIE fighters make no sense as a space design. Moreover all the 'aerodynamic' designs are so cripplingly stupid as spacecraft that they wouldn't ever fly. The Shuttle is already hobbled by its need to be aerodynamic; a fighter certainly wouldn't be able to afford that baggage.
I'm sorry, but I'm going to have to say that's actually a very stupid/ignorant comment. Despite the obvious fancy of Star Wars designs, the TIE design is actually very logical.
(1.) The center of mass lines up pretty much perfectly with the center of thrust. Main propulsion problems solved! In fact, the whole bloody thing is symmetrical, so you don't have to worry much about where and how to put the thrusters... so long as they're symmetrically placed. It's bare bones simple and free from much of the silly sci-fi-ish garbage that gets put on most space ship designs.
(2.) The solar wings, though more practical on something which is not going to have to get shot at, provide rather stellar mounts for maneuvering thrusters. The distances from the center of mass would allow small-medium sized thruster batteries to give good pitch, roll, and admirable rates of yaw control.
In a way, the TIE is actually quite similar to the Star Fury design in terms of potential functionality. Though the Fury is definately more cool...
<Thaeris denies Battuta engineering points>
-Thaeris
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TIE fighters make no sense as a space design. Moreover all the 'aerodynamic' designs are so cripplingly stupid as spacecraft that they wouldn't ever fly. The Shuttle is already hobbled by its need to be aerodynamic; a fighter certainly wouldn't be able to afford that baggage.
I'm sorry, but I'm going to have to say that's actually a very stupid/ignorant comment. Despite the obvious fancy of Star Wars designs, the TIE design is actually very logical.
(1.) The center of mass lines up pretty much perfectly with the center of thrust. Main propulsion problems solved! In fact, the whole bloody thing is symmetrical, so you don't have to worry much about where and how to put the thrusters... so long as they're symmetrically placed. It's bare bones simple and free from much of the silly sci-fi-ish garbage that gets put on most space ship designs.
(2.) The solar wings, though more practical on something which is not going to have to get shot at, provide rather stellar mounts for maneuvering thrusters. The distances from the center of mass would allow small-medium sized thruster batteries to give good pitch, roll, and admirable rates of yaw control.
In a way, the TIE is actually quite similar to the Star Fury design in terms of potential functionality. Though the Fury is definately more cool...
<Thaeris denies Battuta engineering points>
-Thaeris
No. Not at all. The TIE has no maneuvering thrusters. It has no engines for rapid deceleration without a 180 degree flip (the fact that all its engines are on the back are enough to disqualify it). The massive solar panels completely obstruct pilot visibility.
Even the Starfury is not really utilitarian enough to be realistic, though it's making good progress.
It's not a bad design but it's not remotely realistic. 'Realistic' would be an unpiloted, largely unarmored missile bus. I refer you here (http://www.projectrho.com/rocket/index.html) for a thorough discussion of space combat and ship design. Please read it over completely and take a number of physics courses before you decide to call me 'stupid and ignorant'.
In fact I'd appreciate an apology.
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Well, considering that all Star Wars ships seem to have other means than reaction control system for controlling their attitude, I'd say normal approach isn't entirely valid for TIE's and other imaginary ships like that.
Heck, for all we know they could have some inertial maneuvering system within them (though I doubt it). Gyroscopes can be used for that, though they are far from the most viable solution.
More likely they use something silly like aether rudders, but that's beyond the point (and laws of physics).
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They use aetheric rudders. What I'm doing is shooting down questions of realism, not realism-plus-fantastic-technology.
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That doesn't make sense. A human being positioned on a horizontal surface with the thighs pointing out horizontally can be described as "seated" and a human being upright with feet flat against a floor can be described as "standing" even if they're strapped in that way. Standing and sitting are postures, and even if they're maintained artificially they're still postures.
Actually I was just joking, but if you really want to discuss it out I'll have a counterargument ready:
Since there is no gravity the pilot is actually floating.
Do you say someone who's floating upright in the water is standing? Or someone who's floating in the water in a sitting-like position is actually sitting?
I certainly don't since both sitting and standing mean "sitting ON something" or "standing ON something" for me.
Hanging, lying, standing, floating upright... all those share the same bodyposture, but are still different..... So no, the starfury pilot is not standing in my opinion (but as you pointed out correctly he certainly isn't sitting either - at least not the Aurora starfury pilots).
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and if it is some kind of battleships "stealth" ability
Stealth does not exist in space. People will be able to see you from across a star system, no matter what you're flying. Just the fact that the interior of your ship must be almost 300 kelvins hotter than space just to keep you alive will make you extremely easy to spot even if you're running with engines off. And when you do cut engines on, you have a huge neon "I AM HERE" sign coming out your exhaust nozzles.
That doesn't make sense. A human being positioned on a horizontal surface with the thighs pointing out horizontally can be described as "seated" and a human being upright with feet flat against a floor can be described as "standing" even if they're strapped in that way. Standing and sitting are postures, and even if they're maintained artificially they're still postures.
Actually I was just joking, but if you really want to discuss it out I'll have a counterargument ready:
Since there is no gravity the pilot is actually floating.
Do you say someone who's floating upright in the water is standing? Or someone who's floating in the water in a sitting-like position is actually sitting?
I certainly don't since both sitting and standing mean "sitting ON something" or "standing ON something" for me.
Hanging, lying, standing, floating upright... all those share the same bodyposture, but are still different..... So no, the starfury pilot is not standing in my opinion (but as you pointed out correctly he certainly isn't sitting either - at least not the Aurora starfury pilots).
They are sitting/standing on something. In a conventional spacefighter, it would be a seat. In a Starfury, it would be the floor of the cockpit. Just because they're strapped in doesn't mean they're not touching the seat/floor.
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and if it is some kind of battleships "stealth" ability
Stealth does not exist
That is absolutely true.
However, low observability is a different matter altogether and there definitely are ways to reduce sensor footprint of a space ship, just like there are ways to reduce radar echoes on fighter planes so that the echo is indistinguishable of, say, birds. Thermal radiation can be reduced - for a limited time - with good insulation and heatsinks big enough to absorb the waste heat from appliances. Technically with heatsinks big enough it could be possible to even cool the exterior of the ship down to 2.8 Kelvins which would blend it quite nicely to the background temperature of space. Although red shifting that black body radiation spectrum to microwaves would be problematic; perhaps it would be easier to make the surface of the ship emit microwaves at the same spectrum as background radiation is observed. Anyway, there are ways.
Yes, you can not entirely remove your radiation footprint in space. But space is big. Unless you use active sensors or thrusters, it is extremely unlikely that you would be noticed, especially if you park your ship someplace where radar contacts could plausibly be asteroids. Long range reconnaissance missions would be quite plausible with passive sensors, heatsinks and traditional radar signature reducing techniques (surface materials, shape of the ship etc.), but I agree with you that stealth for combat ships at ranges that FS2 usually has is almost entirely impossible.
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It seems we were on slightly different tangents, Battuta.
I did not call you stupid, I have no basis to do that. Nor would I, for that matter. I said your statements had some problems. This is where our misunderstandings must have come into play.
My focus is in terms of the plausibility of an actual design... or if it could in any way be made plausible. Thus, I'm referencing the thruster/engine positions in relation to the center of mass, etc., etc. I get the impression you are questioning combat fightercraft in space in general, which is a different matter. Correct me if I'm wrong.
As far as the TIE goes, I've often heard of the "aetheric... or whatever you call them... rudders," though I've not read any material on how that crap (which it undoubtably is) is supposed to work. Actually, a good deal of the SW references I've seen do mention thrusters, so no, my comments were not invalid. My statements were directed moreso at the general configuration, which is quite reasonable.
Lastly, I apologise if I've offended you.
-Thaeris
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The design cannot be made plausible without the invocation of magical or currently unavailable and non-foreseeable technology. The ship simply has no room or allowance for 'real' engine, weapon, defensive, or control systems (the latter because it makes room for a human pilot.) Run the timescale a little forward and you hit the technological singularity which makes predictions difficult.
We should probably start a new thread on this if we're going to keep discussing it, though.
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Stealth does not exist in space. People will be able to see you from across a star system, no matter what you're flying. Just the fact that the interior of your ship must be almost 300 kelvins hotter than space just to keep you alive will make you extremely easy to spot even if you're running with engines off. And when you do cut engines on, you have a huge neon "I AM HERE" sign coming out your exhaust nozzles.
Have to argue this point. There are lots of infrared objects out there. They're called stars. The infrared universe is actually pretty crowded. As long as you're not observably moving against the background universe, or even just moving along with the ecliptic on reasonable orbit for an asteroid or something, you can be stealthy. (For that matter, approaching from sunward.) There are also ways to cheat on this, like creating baffles to hide most of your drive flare. Depending on how you design your ship, it may not even be necessary. FS capital spacecraft, for example, presumably have a ridiculous number of hulls and even more compartments which aren't in use in combat. They don't need heatsinks at a certain point; they can empty everything outside the main areas of atmosphere and cool the external hull artificially or by radiation.
Also there's the range issue to consider. You are emitting a very small relative signal, in a very big place. There is every reason to believe that you could be undetectable halfway across a solar system, even if you were under weigh and actively radiating, because it takes a really big friggin' antenna to pick you up at that distance, something that would be constantly getting shot away on a combat ship and so isn't likely to be added.
And given light lag, even detecting someone at that distance, they still have a relative degree of stealth.
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"There ain't no stealth in space:"
http://www.projectrho.com/rocket/rocket3w.html#nostealth (http://www.projectrho.com/rocket/rocket3w.html#nostealth)
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What he's declining to mention, again, is antenna size and complexity.
Simply detecting something is also not good enough. You have to classify it as an active spacecraft and a hostile.
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What he's declining to mention, again, is antenna size and complexity.
Simply detecting something is also not good enough. You have to classify it as an active spacecraft and a hostile.
To quote the page (since I don't know anything really):
What Sensors Reveal
When the enemy spots your ship by the exhaust plume, it not only knows that a ship is there, it also knows the ship's exhaust velocity, engine mass flow, engine power, thrust, acceleration, ship's mass and ship's course. Not only can it tell a warship from a cargo freighter with all that information, but it can also tell the class of warship, and maybe make a good stab at determining which particular member of that class it is.
In more detail: as mentioned above, propulsion system's exhaust velocity is revealed by the doppler shift in the emission lines, mass flow is revealed by the plume's luminosity, the thrust is exhaust velocity times mass flow, acceleration is revealed by watching how fast the plume origin changes position, ship's mass is thrust divided by acceleration, and ship's course is revealed by plotting the vector of the plume origin.
This means that painting the ship with camouflage in an attempt to disguise its identity is pretty pointless.
Remember the light-speed lag. Light moves quickly, but not at infinite speed. It takes about eight minutes to travel one astronomical unit. So if you are in orbit around Terra and you observe a spacecraft near the Sun with a telescope or radar, you are actually are seeing where the ship was eight minutes ago. By the same token, if you change course it will be eight minutes until the Sun-grazer ship will know.
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And as we were posisting stealth mainly in the context of running silent with your engine off, you miss the point. Next please.
Also these things become significantly less likely again at range. This is a rather unwarrented application of the principles behind unique sonar signatures of ship propulsion to space combat. At the ranges at which combat occurs in FS, most of those things are reasonable. At interplanetary ranges, and failing to consider the possiblity a ship will not always be running at max thrust/design choices/other factors, not so much.
Also antenna size, fragility, and complexity were not addressed.
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Stealth does not exist but "stealth" (in marks) exist as exit on B-2 F-117 and F-22 it a ability do minimize your profile at enemy scanners. In space ship stealth ability mostly will depend on which side of system star your enemy is or does it hide in shadow of a planet and other objects. Our solar stem is a HUGE empty space which in you can run silent just like subs. Even if enemy find your engine trails when you change your course due to light speed restrictions your data always will be late for few hours.
Only two thing will be sure where they are, planets and installation orbiting them. Other spaceship will move separately, silent, and covered. Gathering together when major assault will be ordered (just like wolf packs in WWII)
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So if the vehicle is manoeuvring via reaction mass, it cannot be stealthy. While you cannot necessarily know the 'peak' output of a given engine using exhaust plume alone, you can determine the technology class once you've observed them for a very short time - photon drives sparkle off dust particles, ion plumes look like x, chemical rockets look like y.
(Photon drives are probably the most stealthy, assuming that the drive is not pointed towards an observer.)
Unless your blackbody emission exactly matches the emission of your background, you will be inherently detectable by passive sensors because all anyone has to do is look in the low-frequency electromagnetic domain and watch for anything that doesn't match the background.
This detects all radiating objects. Yes, you may not immediately know the precise nature of an object, but if you (or a friendly) been there before you can know what use to be there and compare it with what's there now.
Sensor range is only limited by the resolving power of your (radio) telescope.
If we accept Einstein's Gravity Waves, then the radiation doesn't even matter as you can use the gravity waves of any moving object. This is probably harder due to the ludicrous amount of background waves, but not impossible.
(On the other hand, we've not detected gravity waves yet so they may not exist.)
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And as we were posisting stealth mainly in the context of running silent with your engine off, you miss the point. Next please.
Oh, I see well let's look at the webpage for that then shall we?
The maximum range a ship running silent with engines shut down can be detected with current technology is:
Rd = 13.4 * sqrt(A) * T2
where:
Rd = detection range (km)
A = spacecraft projected area (m2 )
T = surface temperature (Kelvin, room temperature is about 285-290 K)
If the ship is a convex shape, its projected area will be roughly one quarter of its surface area.
So take what a Deimos? Which is roughly 700 by 200 by 222 metres?
So one quarter of the surface area is 150,443 m2
Rd = 13.4 * (388) * (81225)
So detection range for a Deimos with engines silent is 422,305,020 km or basically 3 AU.
So given current tech it's not detectable halfway across the solar system, but it is detectable a damn long way away.
And what does attenae size have to do with anything? You think ships aren't going to mount sensors?? How many ships in a realistic universe are going to survive one battle to care about whether their detection systems are intact or not?? Detection I imagine would be done with telescopic lenses, ie like the Hubble etcetera. Just put it behind a strong clear material.
Stealth does not exist but "stealth" (in marks) exist as exit on B-2 F-117 and F-22 it a ability do minimize your profile at enemy scanners. In space ship stealth ability mostly will depend on which side of system star your enemy is or does it hide in shadow of a planet and other objects. Our solar stem is a HUGE empty space which in you can run silent just like subs. Even if enemy find your engine trails when you change your course due to light speed restrictions your data always will be late for few hours.
Only two thing will be sure where they are, planets and installation orbiting them. Other spaceship will move separately, silent, and covered. Gathering together when major assault will be ordered (just like wolf packs in WWII)
The data will be a few hours late but when engagement times are measured in days if not weeks or months does it really matter?? They'll see your burn, your course corrections, etcetera and so on.
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Oh, I see well let's look at the webpage for that then shall we?
Numbers are unsourced and almost certainly wrong. Sure, Chandra can do that. Chandra is in no way practical for a combat ship to carry.
And what does attenae size have to do with anything? You think ships aren't going to mount sensors?? How many ships in a realistic universe are going to survive one battle to care about whether their detection systems are intact or not?? Detection I imagine would be done with telescopic lenses, ie like the Hubble etcetera. Just put it behind a strong clear material.
Antenna size has everything to do with it, as Herra explained. Don't strawman on me, I'm not on you. We're not talking about a realistic universe, either, and you said as much by comparing the Deimos. We're talking about FreeSpace. It's not practical for FS ships, or indeed any combat ships, to carry huge, unwieldly, easily damaged supercooled batteries of CCD cameras in the infrared range or whatever. (Chandra is the size of a small truck, or a smaller FS fighter.) Hubble doesn't have lenses. It's not a refractor, it's a reflector, it has mirrors. No possible clear material in existence could hope to stand up to the kind of weapons fire we are talking about. And you've only opened yourself to poor field of view by bringing in Hubble-like detectors.
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Numbers are unsourced and almost certainly wrong. Sure, Chandra can do that. Chandra is in no way practical for a combat ship to carry.
Well I give the webpage weight on the fact that the two people talking on there are much bigger geeks than you or I.
I'm no science wiz myself. One of the guys most frequently quoted creates boring tabletop boardgames which go for the most realistic space combat possible. Though he does like to think of himself as a greater authority than he is I think.
Antenna size has everything to do with it, as Herra explained. Don't strawman on me, I'm not on you. We're not talking about a realistic universe, either, and you said as much by comparing the Deimos. We're talking about FreeSpace. It's not practical for FS ships, or indeed any combat ships, to carry huge, unwieldly, easily damaged supercooled batteries of CCD cameras in the infrared range or whatever. (Chandra is the size of a small truck, or a smaller FS fighter.) Hubble doesn't have lenses. It's not a refractor, it's a reflector, it has mirrors. No possible clear material in existence could hope to stand up to the kind of weapons fire we are talking about. And you've only opened yourself to poor field of view by bringing in Hubble-like detectors.
Well if you're not talking about a realistic universe then basically you can do any "handwavium" to make stealth possible. Having stealth in a universe is fine if it's consistent with the backdrop and doesn't break suspension of disbelief. Realistic combat is probably fairly boring unfortunately, which is why we have movies like Star Wars and kickass games like Freespace.
Anyway I don't really want or need to debate this. Both our time could be better spent creating new content for Freespace instead (or some other worthwhile endeavour). In many ways talking on the forums is a way to procrastinate doing what should be done, for me at least anyway.
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On the contrary. We are creating new content for FreeSpace by hashing out the rules and functioning of the universe. :P
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And as we were posisting stealth mainly in the context of running silent with your engine off, you miss the point. Next please.
Oh, I see well let's look at the webpage for that then shall we?
The maximum range a ship running silent with engines shut down can be detected with current technology is:
Rd = 13.4 * sqrt(A) * T2
where:
Rd = detection range (km)
A = spacecraft projected area (m2 )
T = surface temperature (Kelvin, room temperature is about 285-290 K)
If the ship is a convex shape, its projected area will be roughly one quarter of its surface area.
So take what a Deimos? Which is roughly 700 by 200 by 222 metres?
So one quarter of the surface area is 150,443 m2
Rd = 13.4 * (388) * (81225)
So detection range for a Deimos with engines silent is 422,305,020 km or basically 3 AU.
So given current tech it's not detectable halfway across the solar system, but it is detectable a damn long way away.
And what does attenae size have to do with anything? You think ships aren't going to mount sensors?? How many ships in a realistic universe are going to survive one battle to care about whether their detection systems are intact or not?? Detection I imagine would be done with telescopic lenses, ie like the Hubble etcetera. Just put it behind a strong clear material.
Hold it! Did you just use Room Temperature for the "Surface Temperature" of a ship in the vacuum of space? I suggest you rework that. The hull temperature of a ship not very close (in astronomical terms) to a star would be hovering about just above absolute zero. Remember that planets are only still hot (comparatively) due to their atmospheres.
Space is about 2.725 Kelvin at any given place/time. I will grant that it might be a little warmer than that, but not by much with no atmosphere to trap the heat. Call it 5 Kelvin.
Using that in your equation come to just under 130,000 km. Extremely viable for stealth purposes, considering that space is enormously empty.
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Hold it! Did you just use Room Temperature for the "Surface Temperature" of a ship in the vacuum of space? I suggest you rework that. The hull temperature of a ship not very close (in astronomical terms) to a star would be hovering about just above absolute zero. Remember that planets are only still hot (comparatively) due to their atmospheres.
Space is about 2.725 Kelvin at any given place/time. I will grant that it might be a little warmer than that, but not by much with no atmosphere to trap the heat. Call it 5 Kelvin.
Using that in your equation come to just under 130,000 km. Extremely viable for stealth purposes, considering that space is enormously empty.
The ship is going to radiate heat will it not?
All objects emit infrared radiation. So the ship will have to be at room temperature (or higher depending on the power systems) and will be radiating that heat into space.
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Thermodynamics doesn't work like that (http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold).
I could write a long post about heat transfer through matters of all sorts (basically the thermal conductivity of the wall of the space ship would be the key to determining the outside temperature of the surface in complete vacuum), but for experimental confirmation, go and see if your house's outside walls are at room temperature during wintertime. If they are, I recommend investing in something called insulation.
Space ships have good insulation because they do not want to waste energy into something like heating when they can get that as a side effect of running any devices, and in most cases space ships need to spend energy on actively cooling the ship instead.
Basically, every spaceship (like everything else, duh) needs to be in thermal equilibrium in order to not freeze or overheat. That means it needs to radiate the same amount of energy as it is receiving from the outside, plus all the excess heat that the systems are producing.
The amount of energy received depends largely on how close to a sun the ship is. For reference, Moon's surface can reach up to 107 degrees celcius during daytime, although Moon's albedo is not exactly the best of all materials. Suffice to say that on the lit side, ship surfaces are hot, on the dark side they are cold, and this has far more relevance to surface temperature than anything that is within the ship. This is not exactly a problem, since every object in space finds it's thermal equilibrium and therefore it would not exactly make it any easier or harder to separate a ship from, say, an asteroid of similar size.
The problem for space ships and stealth comes from excess heat produced by the ship's systems and appliances, and that is the only thing that can basically separate a ship from any lump of rock as far as detection goes.
However, the excess heat usually is transferred away via radiators that radiate the energy into space. Alternatively, the excess heat can be stored in heat sinks when running at stealth mode, sort of like submarines go into silent mode when trying to specifically avoid detection by passive sensors.
And even when using radiators, the ship can simply turn so that the radiators are on the non-visible side to potential observers.
The fact is, there are ways to minimize the EM signature for a limited period of time. Even completely neutralize it, should the need arise, for a while. Simply turn everything off, put a sweater on and use glowsticks for lighting and emergency oxygen supply for breathing.
Radar signature can be masked likewise - just make the ship's surface indistinguishable (via radar signal analysis) from an asteroid.
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And even when using radiators, the ship can simply turn so that the radiators are on the non-visible side to potential observers.
Right you have to radiate waste heat.
You're assuming that
A - the ship knows where potential observers are
B - that observers don't have "all the angles covered" (or at least enough to make the tactic unviable).
Any radiators would also need a fairly large surface area to be effective due to the lack of any substantial medium in space if I'm not mistaken.
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The odds of being in the field of view of even one infra-red sensor in the system are really small. You are underestimating how big space is.
The odds of being in two simultaneously are even smaller.
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Thermodynamics doesn't work like that (http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold).
Irrelevant information.
In space, there is only one way to get rid of your waste heat, and that is to radiate it.
The interior of the craft will be at around room temperature at the very minimum, assuming that the crew inside are alive and relatively comfortable.
Each of your crewmembers will be creating several watts of waste heat all the time, and therefore heating up the spacecraft.
That's before the reactor or other power source comes into the equation.
The skin temperature of the vessel is only defined by the difference between the rate of heat radiated from the skin, and the rate of skin heating by internal conduction.
The latter is much larger than the former at reasonable skin temperatures, so it'll be roughly the same temperature as the internals unless refrigerated.
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I think the best take on stealth in space was the technique used by Minbari from B5.
Instead of trying to reduce amount of signals coming from their ships, they emited additional ones which scrambled enemy sensors and made getting a lock on them impossible.
You may know that Minbari are here, but you won't know how many, what class and where they're going, not to mention you won't be able lock your weapons on them, at least until you get clear visual contact. (correct me if I'm wrong about that, as I haven't watched B5 and I just read about this somewhere, most likely in some thread on TBP board)
Also, that's the matter in which FS also was pretty realistic, as true stealth was only used in a nebula, Lokis in ST and Shivans at the beggining of FS1 were visible on radar, but they weren't identyfied, they most likely seemed like "strange signal" to ship's computer and were so unstable that it wasn't able to aquire a clear lock. Those were the only cannon instances where stealth was used, every other instance is fan-made (I think that using stealth fighter outside of nebula would produce "strange signal" effect on hostile sensors and won't hide the ship completely).
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Thermodynamics doesn't work like that (http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold).
Irrelevant information.
Not entirely...
In space, there is only one way to get rid of your waste heat, and that is to radiate it.
Well, technically you can also eject hot coolant from the ship, but that won't last for long and would make you much more noticeable so it would be counterproductive in this case...
Temporarily storing energy into a heat sink is also a viable option, but limited by the thermal capacity of said heat sinks.
The interior of the craft will be at around room temperature at the very minimum, assuming that the crew inside are alive and relatively comfortable.
Yes, it would. 293 degrees Kelvin is a good approximation for that temperature.
Each of your crewmembers will be creating several watts of waste heat all the time, and therefore heating up the spacecraft.
When sitting, human body produces energy at approximately 116 W power. In vacuum and rest it would be lower, I would hazard to guess something like 40-50 W.
That's before the reactor or other power source comes into the equation.
Yes, and it has already been established that for limited period of time, a ship can either turn most of their systems off or store excess heat in heat sinks. Water tanks would be supremely good heat sink.
The skin temperature of the vessel is only defined by the difference between the rate of heat radiated from the skin, and the rate of skin heating by internal conduction.
The latter is much larger than the former at reasonable skin temperatures, so it'll be roughly the same temperature as the internals unless refrigerated.
The thermal conductivity of the wall and energy loss from the inside through a radiator also matters. If the wall is highly insulating construct and the excess heat from within the ship is transferred to radiators and radiated into space, the skin temperature of the space ship definitely won't reach the same value as within the ship.
Radiator == refrigerator. Heat transfer happens in both cases.
The skin temperature of a space ship is actually sort of difficult to determine. The heat flow through the wall of the space ship depends on the transient in temperature of course, but the surface temperature determines how much the wall is actually radiating into space, while the backflow from space has it's own effect. Things would be far easier to calculate in total vacuum without additional energy sources (close approximation would be deep space, with no nearby star around). I don't have time right now to go through the thermodynamics to estimate what the surface temperature of a ship would be, but I can say with large certainty that it would be fair bit lower than the temperature within the ship's crew quarters.
Dragon: talking about FreeSpace2 nebulas and realism together opens another can of worms... :p
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Ah screw it, I did it anyhow.
Okay, let's build a space ship with the following properties:
-shape spheroid
-radius 10 metres / diameter 20 metres (okay, sort of big but works quite well as a small asteroid as far as radar echoes go)
-surface material: Wrought iron, thermal emissivity 0.94 (black body has thermal emissivity of 1, this is a unitless value)
-main mass of the ship consists of water storage that can work as a heat sink for quite a bit of time.
-distance from sun, 1 AU
-three man crew
-low profile thermal output from systems and crew:
*average heat output from the crew at work: 600 W, rest 150 W combined
*life support 2 kW
*computer systems 1 kW
*passive sensors 500 W
*combined power output at low profile mode: approximately 4 kW
Thermal equilibrium:
Poutput = Pinput
Pinput consists of three variables:
Pspace; the black body radiation of space that hits the entire surface of the spheroid
Psun; the radiation from sun that hits one half of the ship
Psystems; the power consumed and excess heat produced by the systems of the ship.
Essentially, the black body radiation of space is the smallest of these factors:
Pspace = σ * Asphere * T4
σ = Stefan-Boltzmann constant = 5.6704*10-8 W m-2 K-4
Asphere = ship's surface area (4π r^2) = 1256 m^2
T = 3 K (accurate enough)
Pspace = 0.00576883814 W or about 5.77 mW; small enough that it will be ignored in subsequent calculations aside from mentioning that it exists. For a significantly larger and colder object it would have more importance, but our crude stealth ship does not pay any heed to it.
At 1 AU distance rom the Sun, the sunlight is by far the biggest heating factor:
Psun = C * Adisk
C = solar constant = 1.37 kW m-2
Adisk = π r^2 = 314 m^2
Psun = 430.18 kW
For the sake of mental sanity, I am going to handle the halves of the sphere assuming that no heat transfers from the lit side to the dark side. I am also going to assume that the excess heat from systems is evenly distributed to both sides of the sphere. Radiators would just mess my equations up...
Plit = ½Psystems + ½Pspace + Psun
Pdark = ½Psystems + ½Psystems
Hence, the output required at the lit side is about 432 kW, while at dark side it sits at about 2 kw.
From the equation of a non-black body thermal radiation we can now determine the required surface temperature for both halves:
Plit = ε * σ * ½Asphere * Tlit4
Pdark = ε * σ * ½Asphere * Tdark4
where ε is the emissivity of the surface material; other variables should be clear as the sky.
ε = 0.94 for wrought iron surface - very close to black body emissivity.
When the equations are turned around to determine temperature, we get the following:
Tlit = (Plit / [ε * σ * ½Asphere])1/4
Tdark = (Pdark / [ε * σ * ½Asphere])1/4
Tlit = (432000 W / [0.94 * 5.6704*10-8 W m-2 K-4 * 628 m2])1/4 = 337.05 K
Tdark = (2000 W / [0.94 * 5.6704*10-8 W m-2 K-4 * 628 m2])1/4 = 87.92 K
Lit side surface temperature: 337.05 Kelvins or 63.9 degrees Celcius; dark side temperature at 87.92 Kelvins or -185.23 degrees Celcius.
Increasing ship's diameter decreases the skin temperature. Installing separate radiator to take care of the systems' excess energy output reduces the skin temperature further since the temperature doesn't need to conduct through the skin, it can go through the radiator which can be concealed and directional so that it effectively emits the radiation in narrow area of space.
Now here is the main design problem of a stealthy space ship. You can optimize the thermal equilibrium of the ship so that the ship's internal temperature stays at nice comfortable readings as long as the influx of energy stays constant. However, if moved further or closer to energy source, it would need to start using energy to actively cool itself down or heat up. Ideally, the excess heat from systems would actually keep the temperature at constant comfortable values.
It should come as no surprise that the ideal zone for a stealth ship would be at the "green zone" around any star for many reasons:
1. That is the zone where the thermal equilibrium of the ship will settle at habitable temperatures without extra heating or cooling.
2. Everything of interest most likely happens at green zone because habitable planets are there and it is far easier to work in that zone than on outer or inner regions of any system.
Discuss.
Addendum:
In reality, some heat form the lit side would conduct to the dark side. Same applies to asteroids at same region of space, so the difference between an iron asteroid and a stealth ship spheroid would be really, really hard to detect with any sort of infra-red detector and the temperature differences could just as well be addressed to the surface material's thermal emissivity, which varies from asteroid to asteroid depending on the alloy and composition and dust layer on the surface.
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So, can we agree that the surface temperature of a ship would not be room temperature? Missed that part in the post.
You're assuming that
A - the ship knows where potential observers are
B - that observers don't have "all the angles covered" (or at least enough to make the tactic unviable).
And you are assuming that
A - the observers know where the ship is (which sort of precludes any reasonable attempt at stealth anyway)
B - Space is smaller than it is. I know Herra already covered this, but I wanted to get my $0.02 in. They don't call Space an Ocean because it has whales. Space is ****ing HUGE! For example, The total volume encompased by ONE AU is a little bit over 14,000,000,000,000,000,000,000,000 cubic KILOMETERS (Holy ****, that's a bigger number than I thought.) A little over 14 HEPTILLION cubic kilometers. For one AU. (Did I do my math wrong?)
A = (4/3)TTr3
A = (4/3)TT(149,538,000 km)3
A = (4/3)TT(3.3439 x 1024 km3)
A = (4.4585 x 1024 km3)TT
A = 1.4 x 1025, or about 14,000,000,000,000,000,000,000,000 km3
There is a whole ****load of space to hide in. For perspective, a Deimos would take up about 1/454,000,000,000,000,000,000th of that space. Remember that's just one AU.
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Let's take another example of the size of space; angular diameter.
The entire space has angular diameter of 360 degrees for full horizontal and vertical band.
A spherical ship of one kilometre diameter would, at 1 AU distance, have angular diameter of
angle = arctan 0.5 km / 149 598 000 km = 1.91499149 × 10-7 degrees or 0.000689396936 arc-seconds.
Now consider that the Hubble space telescope's Faint Object Camera (FOC) offers maximum resolution of 0.0072 arc-seconds at 3.6*3.6 arc-second field of view, and you're starting to realize how easy it would be to hide in space.
A kilometre diameter ship is a bigass ball and it completely disappears from optical instruments of Hubble's size at this distance. Radar would locate it, but not necessarily - it would require hitting it with a pulse and then receiving the echo...
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Doesn't matter what the volume is, all that matters is that the observer has line of sight.
One would think that in any kind of war, important systems would be equipped with numerous observation stations which continually scan their full field of view for any intruders.
And the point isn't that the solar system is big, it's that it's empty. There's very little place to really hide.
On top of that all of this low-emission ship garble doesn't explain how it gets there in the first place. If FTL is undetectable, lucky for you. But if it's not, you have to jump outside or to the outer edge and approach the system using reaction drives and when you do you will be a heck of a lot more noticeable. And either you coast through the system and then you're out in the open or you have to decelerate and take up position in-cover which will of course attract more attention.
Doesn't matter what the Hubble can do. The Hubble's not scanning for spaceships. There are no spaceships today, but maybe a hundred years in the future. And in a hundred years into future the survelliance gear will make the Hubble look like a cheap pair of binoculars.
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Doesn't matter what the volume is, all that matters is that the observer has line of sight.
One would think that in any kind of war, important systems would be equipped with numerous observation stations which continually scan their full field of view for any intruders.
And the point isn't that the solar system is big, it's that it's empty. There's very little place to really hide.
On top of that all of this low-emission ship garble doesn't explain how it gets there in the first place. If FTL is undetectable, lucky for you. But if it's not, you have to jump outside or to the outer edge and approach the system using reaction drives and when you do you will be a heck of a lot more noticeable. And either you coast through the system and then you're out in the open or you have to decelerate and take up position in-cover which will of course attract more attention.
Doesn't matter what the Hubble can do. The Hubble's not scanning for spaceships. There are no spaceships today, but maybe a hundred years in the future. And in a hundred years into future the survelliance gear will make the Hubble look like a cheap pair of binoculars.
Forgive me, but I call bull**** on most of this post.
The point is that the observer isn't going to have any damn line of sight because he can't find the damn ship so far away in such a vast expanse of space. Unless you think just having a clear line to some point in space means you can find a speck of metal in it. If that were true, anyone in space at any given time should be able to detect everything that ever graced the emptiness of space no matter how far away it is. You also forget that, while light is fast, it isn't instant. An AU is about 8.3 light-minutes. Meaning it takes 8.3 minutes, even with light-speed sensors, to pick up a footprint. That means 8 minutes of additional maneuvering time 16.5 minutes round trip of maneuvering time, as well as 8 minutes after they get pinged for whatever ship it is to turn off the tap and go silent.
It doesn't matter that it's empty. It matters that it's big. You are in error here. Look at it this way. If a tourist gets stranded in the desert, it still takes quite a long time to find him because the desert is so huge and empty it takes forever to cover it. Even if you wait until night and use thermal sensors, it's still going to take a while.
Have you ever heard of lying doggo? It means to be shut down save for the least activity that can be sustained to wait for a hapless ship/vehicle/person whatever to come by. We don't have to explain so much how it got there as we do how long it's been there. Second, a very low acceleration will not produce a very noticable blip on sensors. If you were to accelerate at say, 2 gravities for a long time, you would get to where you're going, albeit slowly, and still be the next best thing to undetectable.
This is my main point of contention. "It doesn't matter what the most high-powered, highest resolution telescope in space can do. In a hundred years things will be different." Way to completely dodge the point. You forget that in a hundred years, things will be different on the other end of the spectrum too.
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I'm torn on this. I'm fairly certain stealth would be next to impossible in space in any reasonable realistic space warfare environment. On the other hand with modern technology we can't even keep track of all the NEOs, so who knows?
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Well, in this case, I think it's possible to write convincing fiction based on both principles. The Honorverse novels (at least the older ones) operated in a stealth is impossible universe, where the most effective tactics are based on misdirection, not on invisibility.
In Charles Stross' Singularity Sky (or better, Iron Sunrise), the space navies play by the "Space is a big place to hide in" book (especially concerning their STL second-strike bombers).
Point is: Both sets of rules can be used to make interesting drama, and that's what we're here for, isn't it? :nervous:
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Well, to be fair, the Honorverse novels operate in the "stealth is hard to actually acheive, but still possible" universe. Going ballistic through a system is undetectable (See: the Argus scouting runs up to the first war), and accelerating at a very slow rate is effectively stealth, usually at anything greater than a few light minutes. However, I will admit that sensor drones make it just about impossible to sneak anywhere effectively. Some of the only exceptions are in unscouted or enemy held systems.
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Damn, you're right. My memory is playing tricks on me again. Yeah, ships not using impellers are considered to be effectively invisible at ranges over a few light seconds, something Honor exploited in "Echoes...", I believe.
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Okay, let's be realistic here.
Any future interplanetary space warfare will end up with RKVs.
They will be unstoppable, undetectable, and completely overpowering. And then MAD will, hopefully, kick in. That or extinction.
Actually, come to think of it, MAD wouldn't work since there's no way to detect an incoming attack and retaliate. So it's just overwhelming first strike or complete trust.
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In other words, reality sucks ass, so let's stick to blowing **** up in FreeSpace. :D
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Actually, come to think of it, MAD wouldn't work since there's no way to detect an incoming attack and retaliate. So it's just overwhelming first strike or complete trust.
Sure it would, same way it did when the first ballistic missiles were designed. Many platforms, only one needs to launch.
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Come again?
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You make MAD work in a world like that by making it impossible to kill all weapons platforms simulatanously, and each one is enough to ensure the destruction of your opponent.
It would be complex, as a math problem, but certainly doable. :P
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Ahh, I gotcha. Yeah, automated (or manned) offworld RKV launchers would do that. Second-strike capability.
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The point is that the observer isn't going to have any damn line of sight because he can't find the damn ship so far away in such a vast expanse of space. Unless you think just having a clear line to some point in space means you can find a speck of metal in it. If that were true, anyone in space at any given time should be able to detect everything that ever graced the emptiness of space no matter how far away it is.
We have no trouble detecting stars thousands of light years away, it should be equally not troubling to detect a vessel radiating a couple AU away.
It doesn't matter that it's empty. It matters that it's big. You are in error here. Look at it this way. If a tourist gets stranded in the desert, it still takes quite a long time to find him because the desert is so huge and empty it takes forever to cover it. Even if you wait until night and use thermal sensors, it's still going to take a while.
Space doesn't have a horizon.
Let me put it this way. The Ocean is a vast place and turbulent place, but it's possible to give an orbital satellite enough resolution to pick up the algae thrown up in the wake of a submarine and to track it's movement (despite being underwater).
Have you ever heard of lying doggo? It means to be shut down save for the least activity that can be sustained to wait for a hapless ship/vehicle/person whatever to come by. We don't have to explain so much how it got there as we do how long it's been there. Second, a very low acceleration will not produce a very noticable blip on sensors. If you were to accelerate at say, 2 gravities for a long time, you would get to where you're going, albeit slowly, and still be the next best thing to undetectable.
The longer you accelerate the longer the interval of time that the enemy has to detect you. Also you forget that going someplace in space requires you to stop as well which means you will be decelerating for an equally long time. Or maybe you just want to pass through the system, but if you're scouting that means you don't know what's there so you're throwing yourself across a system hoping that you don't fly right into the enemy. (ie usually you're tracking his fleet movements and his fleet could be off doing who knows what. Patrols, wargames, logistic transport, etcetera). Of course space is big, you're unlikely to fly right through his formation but you don't necessarily have to.
This is my main point of contention. "It doesn't matter what the most high-powered, highest resolution telescope in space can do. In a hundred years things will be different." Way to completely dodge the point. You forget that in a hundred years, things will be different on the other end of the spectrum too.
In a hundread years the Laws of Thermodynamics will not change.
Ships will still radiate excess heat and they will still use reaction drives.
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Thing is, telescopes can only scan a tiny portion of the sky, Radio Telescopes, however, can scan quite large areas of sky, and are particularly good at noticing energy signatures that weren't there the last time it looked. Our fascination with Supernovae have somewhat encouraged that.
To be honest, I'm more inclined to use the Honorverse approach, the technique described by Herra is designed to be centred on misdirection, that the approaching vessel would be assumed to be a piece of space-debris, of course, the moment it changes direction or velocity, that's going to set alarm bells ringing, so you'd have to drift into the system, and that's a trade of between speed and thrust signature outside the system, get that wrong, and they'll already know you are coming.
I believe the argument is that, no matter what you do, a race at our level of technology or higher would detect something, so the answer lay in convincing whatever is watching that what they are seeing isn't anything to worry about, and the options for that are severely limited in space, especially when you add weapons to the equation, because they add extra power/cooling requirement and would probably lessen any camouflaging abilities of the vessel.
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We have no trouble detecting stars thousands of light years away, it should be equally not troubling to detect a vessel radiating a couple AU away.
Because a star that is a huge object, giving of 'endless' amounts of energy, light and radiation is completely on the same scale as a 1km long starship right?
That's like saying that because you can see a mountain at a few clicks away, you will also be able to see a mouse at the same distance with the naked eye.
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Main advantage for a ship on a clandestine mission: They know exactly where they will be looking at, while counter-intelligence needs to keep looking at everything and everywhere in the system.
Main disadvantage for the same ship: They can only use passive sensors in order to not give their position away, and have also limited means of communication. On the other hand the other side can use active sensors (radar mainly) to locate objects in space.
It all boils down to how good active sensors are available for the static observation posts in the system. If they are good enough to notice a ship beyond their effective passive sensor range, then stealth is not very useful.
However, as was said earlier, stealth is always a relative term and I still say it would be possible to operate secretly within hostile space, with certain limitations, because no one is ever going to have arbitrarily good sensors.
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However, as was said earlier, stealth is always a relative term and I still say it would be possible to operate secretly within hostile space, with certain limitations, because no one is ever going to have arbitrarily good sensors.
I would add to this position of your ship and observer to system star and activity of that sun. Also how good observer knows star system and space object in it.
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Let me put it this way. The Ocean is a vast place and turbulent place, but it's possible to give an orbital satellite enough resolution to pick up the algae thrown up in the wake of a submarine and to track it's movement (despite being underwater).
And look once again at the relative ranges here. A satellite orbits, call it 200 miles above the Earth. The algae wake of a submarine is several kilometers long.
Not move the satellite 150 million kilometers out of the way and reduce the size of the target.
The longer you accelerate the longer the interval of time that the enemy has to detect you. Also you forget that going someplace in space requires you to stop as well which means you will be decelerating for an equally long time. Or maybe you just want to pass through the system, but if you're scouting that means you don't know what's there so you're throwing yourself across a system hoping that you don't fly right into the enemy. (ie usually you're tracking his fleet movements and his fleet could be off doing who knows what. Patrols, wargames, logistic transport, etcetera). Of course space is big, you're unlikely to fly right through his formation but you don't necessarily have to.
In order: Yes. Yes, however, stopping at close range is not necessarily your goal; once again, space is flippin' HUGE. Again, the odds of you flying into an enemy fleet in one of the 14 HEPTILLION cubic kilometers in one AU is so astronomical my calculator (TI-84) overflows with the numbers before it gets to it (past 9.99 x 1099).
Ships will still radiate excess heat and they will still use reaction drives.
1) yes, but maybe more effectively than you think. Think aircraft. Some of them are really hard to get a good look at on radar and manage to pass themselves off as BIRD SIZED. What makes you think a spaceship won't be able to do the same thing, but as a bit of debris or as a sensor "ghost" instead?
2) You think so. We have no real idea. Maybe we'll have gravitic drives by then. No one knows.
Main disadvantage for the same ship: They can only use passive sensors in order to not give their position away, and have also limited means of communication. On the other hand the other side can use active sensors (radar mainly) to locate objects in space.
I think something we're missing is the necessarily long-term missions that would go on, since accelerating too fast would be a Bad Thing. We could be talking weeks without communications, almost like navies back before telegraphs.
I would go further, ans say that the smaller object is a sewing needle.
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Let me put it this way. The Ocean is a vast place and turbulent place, but it's possible to give an orbital satellite enough resolution to pick up the algae thrown up in the wake of a submarine and to track it's movement (despite being underwater).
I assume you can prove this, because AFAIK non-acoustic ASW is, was, and forever shall be a load of crap.
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I think I read something like this in a Tom Clancy novel once.
Now, detecting a surface ship via its algae wake, that's certainly possible, but submarines?
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Let me put it this way. The Ocean is a vast place and turbulent place, but it's possible to give an orbital satellite enough resolution to pick up the algae thrown up in the wake of a submarine and to track it's movement (despite being underwater).
I assume you can prove this, because AFAIK non-acoustic ASW is, was, and forever shall be a load of crap.
Well, the surface of the water the submarine is beneath will bulge a little... Detecting that in a rolling ocean, however, will not happen as far as I can tell.
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Let me put it this way. The Ocean is a vast place and turbulent place, but it's possible to give an orbital satellite enough resolution to pick up the algae thrown up in the wake of a submarine and to track it's movement (despite being underwater).
I assume you can prove this, because AFAIK non-acoustic ASW is, was, and forever shall be a load of crap.
Well, the surface of the water the submarine is beneath will bulge a little... Detecting that in a rolling ocean, however, will not happen as far as I can tell.
Seriously? Seriously?
Go fill a bowl with water.
Put a pencil in it.
Do you get a pencil-shaped bulge? Huh? :p This is an incompressible medium. It's really hard to produce local topological changes just by displacement.
Now, granted, there's propagation speed to be taken into account when the submarine moves.
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My friend, you have taken that far out of context...
....Though I will admit that was a tremendously amusing response...
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I really don't get what you were going for, then.
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What, you mean the ocean will rise detectably because there's a submarine in it? o.0
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I've seen it noted on several science programs on television before. I believe what I was (rather ignorantly) referencing was the "Bernoulli Hump." Of course, that might be the wrong reference as well. I may need to do a little more research. Here's an interesting site for this discussion:
http://www.behindbluelines.com/2009/07/22/what-is-state-of-the-art-in-submarine-detection/
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I know all about this.
It's not practical. It only works for about 100 feet of depth. On a good day you can see that deep in shallow water with your naked eye. The stuff from '70s patent was pure fantasy. Nothing has really changed in that regard. So you deny everything down to 200 feet these days, maybe. Ultimately MAD is going to be the sensor system that eliminates the submarine if any does.
Acoustic detection and tracking is still king. You look for a Collins or a Gotland not by their noise, but by their lack of noise. (Yes, you can do that, much like you can see a car painted black on a starlit night because it's darker than the background.)
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I've seen it noted on several science programs on television before. I believe what I was (rather ignorantly) referencing was the "Bernoulli Hump." Of course, that might be the wrong reference as well. I may need to do a little more research. Here's an interesting site for this discussion:
http://www.behindbluelines.com/2009/07/22/what-is-state-of-the-art-in-submarine-detection
The hump will only occur if the submarine is very close to the surface, as NGTM-1R said.
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I seem to recall talk of being able to detect 'knots' in the water caused by a submarine turning? It was developed, iirc, from a technique that was used to avoid torpedos, where a sub would make a sharp turn in the water, and the turbulence it created would confuse the torp?
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Let me put it this way. The Ocean is a vast place and turbulent place, but it's possible to give an orbital satellite enough resolution to pick up the algae thrown up in the wake of a submarine and to track it's movement (despite being underwater).
I assume you can prove this, because AFAIK non-acoustic ASW is, was, and forever shall be a load of crap.
8 or 10 years ago a Canadian Firm was launching some sort of satellite but the US Government was like "no, it's too good. It can track our submarines" so I think they had to dumb it down a bit to appease the yanks. Or so the news told me.
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If I have to choose between believing anything written here, or things written at projectrho, I'll go with the latter.
20 guys with degrees beats you guys here (that includes you too Herra, sorry, but quantity does matter too). If they say no stealth in space...then no stealth in space.
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If I have to choose between believing anything written here, or things written at projectrho, I'll go with the latter.
20 guys with degrees beats you guys here (that includes you too Herra, sorry, but quantity does matter too). If they say no stealth in space...then no stealth in space.
Herra brings up issues they don't even address and you just assume they forgot them because they're awesome? wtf kind of logic is that?
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Herra brings up issues they don't even address and you just assume they forgot them because they're awesome? wtf kind of logic is that?
I know what forum the two main guys frequent if anyone wants me to relay some counterpoint.
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It's called "field of view". As anyone who's dabbled in astronomy can tell you if you wish to look deep, then you must also look narrow. The more magnification you apply, the less your field of view encompasses. To make matters worse, electronic instruments remain unable to simply look and instantly detect faint objects. (The human eye has them beat all to hell in this regard, amusingly.) Hubble and Chandra have to take long exposures for their shots, the fainter (and distance increases faintness exponentionally) the longer you have to look to detect it with your electronic eyes. (Using even very good 23" amateur equipment, faint objects take twenty or thirty minute exposures. Hubble and Chandra usually take longer ones looking for even fainter objects.) Even allowing for magical future tech, while there's very little possiblity you'd be sneaking up to within realistic shooting range of someone, at interplantary distances there's every reason to believe you could simply not be looked at for hours or even days while they try to sweep the whole sky.
Active sensors like radar are not viable objects for system surveillance due to range gate issues. The AEGIS's SPY-1 could probably get a radar return off the Moon, but by the time the Moon return got back to the receiver it would be arriving simulatanously with returns from other, much closer objects painted by radar pulses sent out much more recently. If you wish to track objects close-in, you must dial up your pulse rate to do so accurately. Slowing it down to the rates you would use to track objects at even mere interplanetary distances is not only impractical, but downright dangerous since someone could launch an attack in the time between your pulses. There are ways to get around this, like "chirp" radars that radiate each pulse on a slightly different frequency so the computer can distingush them, but even then there are limits that keep the range gate well below interplanetary, much less covering a whole solar system.
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Look, I'm not saying stealth in space is definitely possible or definitely impossible.
I'm just doing the maths in order to determine what kind of sensor equipment you need in order to pick up a ship like this and actually determine it is in fact a clever ruse and not an asteroid.
The requirements are:
-You have a radar system that has already registered and archived the orbits of all legitimate objects within it's range
-is able to scan the area in a reasonable time; this time is the minimum grace time for a stealth ship. No radar system can immediately track the whole sky. If it takes a week to do a full sweep of the space, then it can take up to a week to detect the new object. On average, based on probabilities, it takes three and a half days.
Radar echoes are easy to minimize, however. A system that is able to detect every particle in, say, Saturn's belt would be impressive indeed. There's also places with a lot of junk gathering to them with very chaotic orbits; trojan asteroid zones come to mind first and foremost. Determining these orbits would pretty much require solving +three body problem which is, for current mathemathics, rather impossible. You can get approximations, sure, but you would need arbitrarily small dt (time differential, for not-mathematically inclined) values to really approach the accuracy you need for this kind of thing.
It's also possible to do the Han Solo and simply attach the spy ship on some already existing object. Without getting a good look at the asteroid or comet or whatever the ship attached itself to with good old Mark I, it would be very, very difficult to determine that it's there at all.
Optical detection of one kilometre wide target at 1 AU distance, beyond detecting a point source of radiation of course, would require resolution beyond 0.000689396936 arc-seconds, and again the system has a certain time it needs to sweep the whole sky. It can't do it instantaneously. You can't really fit a fish-eye lense with large enough CCD cell to cover half the sky immediately; even if you could, image analysis would become a problem.
As far as thermal imaging goes, same limitations apply. Sure you can detect a point source of light, but without more detail you can't know what the surface material is and without that, you can't know what the emissivity rates are. Sure, you can get some hints out of spectrum analysis, but that just reveals the element if even that; and element alone can't give you exact knowledge of the surface's emissivity rates which is required in order to accurately determine the surface temperature, which is required to differentiate from non-ship targets. It would most likely be fairly easy to pass between the surface variations of asteroids as far as surface temperature of the ship goes.
However, the further the ship is from the green zone, the more difficult it is to remain hidden, because the average temperature gained from solar heating either drops or rises too low to sustain livable environment and active heating needs to be engaged.
Still, I'm just bringing up all the difficulties in first of all detecting a ship - even a big'un at that - at interplanetary distances. Moreover I'm concentrating on the difficulties on how to determine that a target is actually a ship, especially if it wants to pass off as an asteroid or other naturally occurring target.
Thus far my conclusion is you need insanely good sensor equipment in order to make stealth impossible within any sort of reasonable range. If you want to handwave efficient enough sensors into existence for your scifi universe, sure you can negate the possibility of stealth ships, but you should still remember to limit the range of absolute detection and remember issues like light speed that make simultaneous events not simultaneous at all.
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Interesting discussion. Here's my take;
1) It makes no sense to have manned fighters in space. Providing for the pilot's safety while attempting to maximize maneuverability, acceleration, weapons capacity and spacecraft integrity would be a gross exercise in futility. Just the environmental factors in space would put the pilots at unreasonable risk, let alone actual combat stresses. I could certainly see unmanned, remote controlled armed drones with human pilots on nearby carriers connected via VR being much more effective in space ship-to-ship combat. The fighters would be much more maneuverable and could accelerate/decelerate much more quickly without having to worry about the pilot's physical limits and the added mass necessary for life support, displays and controls. No cockpit means no structural weaknesses due to the canopy and the required position of the pilot to maximize visibility. Long range and reconnaissance missions would have to be manned, but larger, faster, lightly armed ships with the following characteristics would be used.
2) Heat signatures can't be masked, but they can be directed away from an enemy by using strategically placed heatsinks and an active heat management system that would radiate heat in the opposite direction. It's also possible to store heat for short periods of time and radiate it later. Well insulated hulls and/or cockpit environments would be a necessity for the safety of the crew, and nearby objects could be used to mask thermals effectively.
3) There are better ways of dealing with electromagnetic signatures than simply hiding them. The real future of stealth technology isn't in minimizing radiation sources and surface area profiles, but in using electronic warfare techniques. Any electromagnetic wave can be duplicated and emitted 180 degrees out of phase to cancel the original signal out. Not only that, but it's possible (today our military uses this emerging technology with great success) to mask the original signal and emit a fake signal which will misdirect the enemy to another location kilometers away. Minimizing radiation sources has its place, but active electronic warfare is much more tactically valuable.
4) Propulsion and thrust doesn't have to be employed in space like it does in an atmosphere. The reason why atmospheric fighters must always employ forward or downward thrust is because it's used to generate lift and the craft's forward velocity is affected by drag. In space, drag would be minimized, gravity fields would be minimal or at least distant enough not to immediately present a solid object/instant deceleration hazard. Short, high intensity bursts of thrust in the opposite direction of the desired course are all that's required to move an object along in space. Stealth techniques could employ either tighter burn times or longer, low intensity burns to blend in with background noise would be the order of the day.
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Hmmm...
We could totally pull off a "realistic" space fight by hacking sentry guns to have thrust, then spam them en masse between two Colossi.
Also, EMP weapons would probably be used much more frequently and to greater effect against drones than against humans, so maybe that serves as a pseudoscience reason for why FS bothers to use manned fighters at all. Plus, if you broadcast a giant wall of EM noise, you'd cut off any communication between mothership operators and drones, unless they were using some sort of entanglement comms.
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Also, EMP weapons would probably be used much more frequently and to greater effect against drones than against humans, so maybe that serves as a pseudoscience reason for why FS bothers to use manned fighters at all. Plus, if you broadcast a giant wall of EM noise, you'd cut off any communication between mothership operators and drones, unless they were using some sort of entanglement comms.
This.
Makes.
No.
Sense.
How is an electronically controlled fighter without a human pilot any different from one with electronic controls and a human pilot?
Unless you're suggesting future spacecraft won't be entirely fly-by-wire.
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EMP's not that effective anyways. We have the means now, today, to harden effectively against the EMP of a nuclear blast. We can do it against a direct strike from a bolt of lightning, too.
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The only real advantage, stealthwise, of unmanned ships is the fact that you save on having to heat some kind of living area and having to supply breathing and other needs.
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One more strike against unmanned: intuition. Heuristics and gut feelings may not be a science, but they can make a difference.
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One more strike against unmanned: intuition. Heuristics and gut feelings may not be a science, but they can make a difference.
Yeah, but intuition is slow. Probably too slow.
Has a better place in overall command-and-control.
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Slow is better than non-existant.
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The only real advantage, stealthwise, of unmanned ships is the fact that you save on having to heat some kind of living area and having to supply breathing and other needs.
Smaller, faster and more maneuverable ships are harder to hit in a dogfight, where stealth isn't really a factor. Human controlled drones with AI aided evasion and threat detection would present more of a challenge to computer controlled point defense. Sensory interfaces could allow for extra sensors (including point defense targeting data and shipboard target identification systems) to be routed to the human pilots, thus giving them the equivalent of extra sensory perception, which would be far superior to an unquantifiable sense of "intuition"
Also, EMP would present a host of problems for not only your ship-to-ship comms, but your enemies' as well. Hardened onboard AI could keep the drones intact long enough for the pilot interfaces to be re-established. The change in the flight characteristics may even confuse the enemy fighters, thus giving the tactical advantage back to our side.
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You do realize that "more maneuverable" does not equate to pitch and yaw rate, correct? In a [next best thing to] frictionless environment, maneuverability is limited to acceleration rates. Granted, an unmanned craft could theoretically withstand higher G forces, things still tend to break.
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You do realize that "more maneuverable" does not equate to pitch and yaw rate, correct? In a [next best thing to] frictionless environment, maneuverability is limited to acceleration rates. Granted, an unmanned craft could theoretically withstand higher G forces, things still tend to break.
Ah, but they can still do a barrel roll...
Here's a killer though: You can't evade a laser. End of space dogfight. :nervous:
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You do realize that "more maneuverable" does not equate to pitch and yaw rate, correct? In a [next best thing to] frictionless environment, maneuverability is limited to acceleration rates. Granted, an unmanned craft could theoretically withstand higher G forces, things still tend to break.
Of course it does! Any change in ship direction has consequences to the pilot. Barrel rolls equate to a centrifugal force that may be equal to several times what a human's body can tolerate without catastrophic injury to the blood vessels in the head and feet of the poor pilot. Remember, the pilot's blood and internal organs will tend to continue to travel in one direction while the ship pitches, yaws or accelerates in another. Do this too abruptly, and the human body will definitely experience trauma.
This isn't a new concept. Pilots of modern combat aircraft cannot survive the maneuvers that their aircraft could do quite easily. Avionics are programmed to actually limit the capabilities of the aircraft to protect the pilots from themselves. Thus we have force feedback on the controls of the fighters.
Ah, but they can still do a barrel roll...
Here's a killer though: You can't evade a laser. End of space dogfight.
Lasers are lousy weapons, too easily defeated by simple means. A reflective surface almost completely mitigates the damage done by a direct hit, and you still have to aim the thing to hit a small moving target hundreds or thousands of meters away. Try to paint a 150cm moving target from 100 meters away with a laser pointer sometime and see how hard it would be to evade that sort of weapon.
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No, I mean that if a ship pitches or yaws in one direction does NOT mean that the ship will then fly in the direction it is pointing. At least, not until thrust is applied.
I'm... not exactly sure what that barrel rolls comment means. If a ship is in space, it is probably moving very fast, and engaging targets (if at all) at a rather long range (hundreds, if not thousands of Km, at the very least).
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Here's a killer though: You can't evade a laser. End of space dogfight. :nervous:
Well, technically, you should, y'know, evade anyways at random so his targeting solution's not so good, but...
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Try to paint a 150cm moving target from 100 meters away with a laser pointer sometime and see how hard it would be to evade that sort of weapon.
This is what those newfangled, whatchamadingits, computers I think they're called, are for.
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No, I mean that if a ship pitches or yaws in one direction does NOT mean that the ship will then fly in the direction it is pointing. At least, not until thrust is applied.
I'm... not exactly sure what that barrel rolls comment means. If a ship is in space, it is probably moving very fast, and engaging targets (if at all) at a rather long range (hundreds, if not thousands of Km, at the very least).
What is the point of that, other than to orient your weapons in a direction other than your flight path? This would be an effective dogfighting tactic, but you will eventually have to change directions, and rapidly. At the velocities I can imagine in a space dogfight, even re-orienting the human body quickly enough would result in injury.
Even computers have their limits... The lag between the targeting, orienting a turret, and firing would be enough for a good pilot to easily evade such a weapon. The very reason a human pilot, even that of a drone, is necessary is that humans don't act rationally and we are too unpredictable for a computer to easily dispatch.
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You do realize that "more maneuverable" does not equate to pitch and yaw rate, correct? In a [next best thing to] frictionless environment, maneuverability is limited to acceleration rates. Granted, an unmanned craft could theoretically withstand higher G forces, things still tend to break.
Of course it does! Any change in ship direction has consequences to the pilot. Barrel rolls equate to a centrifugal force that may be equal to several times what a human's body can tolerate without catastrophic injury to the blood vessels in the head and feet of the poor pilot. Remember, the pilot's blood and internal organs will tend to continue to travel in one direction while the ship pitches, yaws or accelerates in another. Do this too abruptly, and the human body will definitely experience trauma.
This isn't a new concept. Pilots of modern combat aircraft cannot survive the maneuvers that their aircraft could do quite easily. Avionics are programmed to actually limit the capabilities of the aircraft to protect the pilots from themselves. Thus we have force feedback on the controls of the fighters.
I think you misunderstood what Scotty was saying.
Maneuverability in an airplane is a two fold thing. You have elevators that control the angle of attack vertically, rudders that control angle of attack horizontally and elevators that controls the attitude of the ship around it's longitudinal axis.
However, as far as maneuverability goes, the most important term for any combat airplane is actually defined by one factor: The maximum sustainable amount of lift.
This may sound counterintuitive, but all aircraft turn by using lift and thrust. They change their attitude with control surfaces, but the turn rate of the aircraft is entirely dictated by the amount of lift that it produces. When an aircraft rolls left or right, the lift force from wings is still headed "upwards" in relation to airplane - and now the vector is pointing to one side of the plane. So it has one component pulling the plane up and one component pulling the plane sideways.
The sideways force acts as a centripetal force and the airplane ends up in a circular motion known as "turn". Meanwhile, since part of the lift is now used to maintain lift, the airplane begins to lose altitude if nothing is done to correct the situation. Normally this is done by increasing angle of attack, which increases the total amount of lift so that the downward component is equal to airplane's weight and the plane won't descend during the turn.
Now, the amount of centripetal force generates centripetal acceleration which is known as the g-force in the turn. It's also obvious that when angle of attack is increased further, the centripetal force increases, forcing the aircraft on a smaller turn radius. Typically, each aircraft has it's own "sweet spot" or maximum cornering velocity where pulling back the stick will result in the largest amount of lift while the airplane's nose also pitches up at fastest rate. This is the velocity where the airplane turns the best - for a brief period of time. This is used as a break turn and it's typically employed to get inside a missile's - or a pursuing plane's - turn radius in an attempt to escape destruction.
However, increasing angle of attack is a dramatically energy-consuming maneuver since it increases the drag of the airplane greatly. As a result, more thrust is needed to maintain airspeed. Terms like maximum sustained turn rate come into play; an optimal turn rate at which the airplane's engines can produce enough thrust to counter the additional drag and maintain that airspeed. This is the single most important aspect of an airplane's maneuverability and comes into play especially in a sustained close range dogfight.
Now that we have established the aviation terminology for maneuverability, let's take a look at the situation where there's no atmosphere.
We soon notice that pitch, roll and yaw changes do nothing to your vector. You're just spinning around your center of gravity while going in the exact same direction as before. Sure, you can knock yourself out by spinning too hard but as you're going in a straight line at constant velocity, you'll be easy target to anything hostile, whether you're conscious or not. Since there's no lift to align towards the direction you want to turn to, you have to do something different.
In order to actually change your vector, course, travel direction or whatever you wanna call it, you need to fire your thrusters into the direction opposite from where you want to go. Also, ideally you should keep your thrust vector directed towards the desired center of turn for the duration of the turn. If you have static main thrusters, you need to turn your ship so that it is flying "sideways", and then engage full thrust and turn the ship slowly so that the heading of the ship is pointing towards that imaginary spot in space that you are looping around, much like a stone in a sling.
When you cut the thrusters, your ship will continue from the circular motion tangentually to the direction you want to be going to.
And much like in aviation, your ship's ability to produce thrust (actually, thrust to mass ratio, or acceleration in other words) is essentially the defining factor when measuring maneuverability in space. Certainly, pitch roll and yaw rates have their importance, but it is much easier to make a pivot ball space ship than one that can produce a lot of acceleration for a long time; propellant increases ship's weight significantly, so we have a catch-22 or something; you can prolong the operational combat time of a space ship by increasing propellant load, but if you increase the mass too much, the ship's turn rate suffers and it will die. But if you reduce the amount of propellant, the ship might run out of thrust during the fight and die...
Also, the reason why removing pilot increases possible maneuverability is, first and foremost, the pilot's health which is no longer the limiting factor in acceleration. Machines can take a lot more acceleration than human body can - in a sustained turn. Sure, humans can survive +100G collisions if no actual injury happens (refer to the rocket sled (http://en.wikipedia.org/wiki/Rocket_sled) experiments) but in a sustained turn machines can function longer and better.
Secondly, performance is improved by removal of weight - pilot weight, controls, life support, cockpit structure, seat, cup holders and all the pilot's equipment for emergencies. Reduced mass means the acceleration is improved, which means life and death in space combat.
NGTM-1R: that only works at ranges where the laser beam takes some time beyond nanoseconds to reach the target. Even a lightmicrosecond might be sufficient, but that's a long distance still... and evading like that consumes propellant like there's no tomorrow.
Also, regarding this:
Lasers are lousy weapons, too easily defeated by simple means. A reflective surface almost completely mitigates the damage done by a direct hit, and you still have to aim the thing to hit a small moving target hundreds or thousands of meters away. Try to paint a 150cm moving target from 100 meters away with a laser pointer sometime and see how hard it would be to evade that sort of weapon.
Obviously, you have missed something... (http://www.hard-light.net/forums/index.php?topic=65471.0)
Sure, as infantry weapons they would be massively impractical. For other purposes... they have potential.
Also, barrel roll is just a reference to Star Fox games where Barrel Roll is some sort of super move. Kinda like Mario when he's eaten the Star. It's not even a real barrel roll, just a rapid roll... immortalized by a hare shouting you to DO A BARREL ROLL DO A BARREL ROLL DO A BARREL ROLL all the goddamn time.
At the velocities I can imagine in a space dogfight, even re-orienting the human body quickly enough would result in injury.
Linear velocity has no effect on angular velocity. And human body can tolerate high angular velocities quite a bit better than linear acceleration, mainly because the dimensions of a human body are at average maximum about one metre from center of gravity.
Sure, it's disorienting as hell but doesn't actually damage a human being until the spin rates are rather insane.
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One more strike against unmanned: intuition. Heuristics and gut feelings may not be a science, but they can make a difference.
Gut instincts are tantamount to guessing. You can make an algorithm which has a better chance of being right.
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There is no stealth in space. (http://www.projectrho.com/rocket/rocket3w.html#nostealth) Apparently not even with today's technology. Sorry guys. Might be possible with some SF gadgetry.
Although RKVs are stealthy on the way in!
Okay, Ionizd, you are holding a number of understandable misconceptions.
I'm... not exactly sure what that barrel rolls comment means. If a ship is in space, it is probably moving very fast, and engaging targets (if at all) at a rather long range (hundreds, if not thousands of Km, at the very least).
Very much so, to the point where maneuverability is totally irrelevant. Ships will engage at speeds of thousands of kilometers per second (ballpark figure), essentially acting as two bullets shot at each other, except the bullets are also shooting at each other. Maneuvering will mean nothing because there'll be only a small cone in which one can alter one's vector - and the enemy will fill that zone with debris.
.
Even computers have their limits... The lag between the targeting, orienting a turret, and firing would be enough for a good pilot to easily evade such a weapon. The very reason a human pilot, even that of a drone, is necessary is that humans don't act rationally and we are too unpredictable for a computer to easily dispatch.
Unfortunately totally untrue. Humans are more predictable than computers and are far too slow to keep up with weapons systems that can be aimed, fired, and transited essentially instantaneously.
Furthermore it's not a matter of 'dodging' at all. You're just going to be running into a field of debris, mines, or waiting missiles at unsurvivable velocities. Space shotguns, and there's nothing to be done. Sadly deterministic.
Smaller, faster and more maneuverable ships are harder to hit in a dogfight, where stealth isn't really a factor.
There are no dogfights in space. Bullets can't dogfight.
Human controlled drones with AI aided evasion and threat detection would present more of a challenge to computer controlled point defense. Sensory interfaces could allow for extra sensors (including point defense targeting data and shipboard target identification systems) to be routed to the human pilots, thus giving them the equivalent of extra sensory perception, which would be far superior to an unquantifiable sense of "intuition"
Humans can't perform the necessary calculations fast enough. Not that they'd be needed. You can plot an opponent's potential vectors and engage them hours in advance.
Also, EMP would present a host of problems for not only your ship-to-ship comms, but your enemies' as well. Hardened onboard AI could keep the drones intact long enough for the pilot interfaces to be re-established. The change in the flight characteristics may even confuse the enemy fighters, thus giving the tactical advantage back to our side.
Even modern technology is essentially immune to EMP.
There will be no fighters in space. Missile buses maybe. Maneuverability means nothing; thrust is everything.
Lasers are lousy weapons, too easily defeated by simple means. A reflective surface almost completely mitigates the damage done by a direct hit, and you still have to aim the thing to hit a small moving target hundreds or thousands of meters away. Try to paint a 150cm moving target from 100 meters away with a laser pointer sometime and see how hard it would be to evade that sort of weapon.
There is no simple means to defeat a laser. The reflective-armor idea is an urban myth; any combat laser will smash through the mirror, since no mirror is 100% efficient and the leak will certainly vaporize the armor. Similarly, ablative armor can be easily defeated by pulse laser systems. Active defenses in the form of dispersed clouds of gas (an artificial atmosphere) might have some success, but the last analysis I read suggested they fail, again due to the pulse laser technique.
Laser aiming is easier than any other form of aiming, thanks to computers and the awesome travel speed. Within effective range, lasers cannot be evaded. The key, however, is that they're fairly short-range due to the lightspeed lag (apparently they aren't subject to inverse square law? How odd...)
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There is no simple means to defeat a laser. The reflective-armor idea is an urban myth; any combat laser will smash through the mirror without losing more than a fraction of its energy. Active defenses in the form of dispersed clouds of gas (an artificial atmosphere) might have some success, but the last analysis I read suggested they fail.
Laser aiming is easier than any other form of aiming, thanks to computers. Within effective range, lasers cannot be evaded. The key, however, is that they're fairly short-range due to the inverse square law.
Inverse square law works ideally for point sources of light, but lasers are ideally coherent beams of light with diameter of d to begin with.
Let's see the beam attenuation in percentages of intensity:
Intensity = power / area
distance, beam diameter, area, intensity percentages of original:
0 m, 10.0 cm, 78,5 cm^2, 100%
1000 m, 10.1 cm, 80,1 cm^2, 98.05%
2000 m, 10.2 cm, 81,7 cm^2, 96.12%
Traditionally, the inverse square law states that when distance doubles, intensity quarters. This is obviously not the case here. However, the drop in intensity does follow the inverse square law, and the intensity will start dropping faster as distance increases but it doesn't mean that the intensity of the laser beam itself would follow the same law.
Of course at reasonably long distances it starts to work better; for example when viewing at distances 100 kilometres and 200 kilometres where the beam diameter has widened up to 20 cm and 30 cm respectively, the difference at the intensities is more drastic but still doesn't exactly follow the inverse square law.
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Some amusing designs suggest firing a laser at a distant mirror, then using that mirror to focus the (diffuse, so reflectable) beam onto the target. Interesting plan!
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There is no stealth in space. (http://www.projectrho.com/rocket/rocket3w.html#nostealth) Apparently not even with today's technology. Sorry guys. Might be possible with some SF gadgetry.
His numbers are bad, particularly about exposure times (try telling that bit about 30-second exposure for a magnitude 12 object to an astroimager and they'll laugh like hell), and again he's just basically talking out his ass about detection equals assessed as target.
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There is no stealth in space. (http://www.projectrho.com/rocket/rocket3w.html#nostealth) Apparently not even with today's technology. Sorry guys. Might be possible with some SF gadgetry.
His numbers are bad, particularly about exposure times (try telling that bit about 30-second exposure for a magnitude 12 object to an astroimager and they'll laugh like hell), and again he's just basically talking out his ass about detection equals assessed as target.
'He' isn't saying anything. His sources are all cited and he provides contact information if you'd like to dispute it. I'm certainly willing to believe there are problems with the analysis but I must say that the point seems well-substantiated.
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Combat wasps.
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His sources are all cited and he provides contact information if you'd like to dispute it.
His sources are not cited, because they are not sources in any meaningful sense of the word, they are people talking who may or may not know what they are talking about. You are ascribing a validity to the "source" that it does not have.
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His sources are all cited and he provides contact information if you'd like to dispute it.
His sources are not cited, because they are not sources in any meaningful sense of the word, they are people talking who may or may not know what they are talking about. You are ascribing a validity to the "source" that it does not have.
I'm quite aware it's not up to academic standards, but nonetheless, I am for the moment accepting the gist of the argument even if I did look askance at some details.
And his sources are certainly cited; while their validity is questionable, he at least provides us a way for us to access that questionability.
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Herra brings up issues they don't even address and you just assume they forgot them because they're awesome? wtf kind of logic is that?
Herra might be a physicists, but what is his field of specialization?
I won't trust a proktologists with a brain surgery, or vice-versa. Suffice to say, projectrho is a site dedicated to just one thing - future in space. They get questions and e-mails, and I'm pretty sure all the relevant questions have already been raised over the years. Could they be wrong? Yes. Could Herra be wrong? Yes.
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So far this has been very basic applications of mathemathics and a bit of thermodynamics thrown in for good measure.
Any physicist regardless of their specialization fields should be able to do this stuff. It's like saying you would need to study medieval literature in order to be able to tell your kid a bedtime story.
It might help but it's not required for reading Snow White aloud.
And like I've already stated, all this really depends on what kind of detection and identification systems are available. Which we can't know, but we can know what kind of abilities they should have to detect and identify a target as a space ship. And it is not as easy as some in this thread seem to suggest, if the ship in question is not broadcasting a transponder signal or radiating like hell.
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Also, EMP weapons would probably be used much more frequently and to greater effect against drones than against humans, so maybe that serves as a pseudoscience reason for why FS bothers to use manned fighters at all. Plus, if you broadcast a giant wall of EM noise, you'd cut off any communication between mothership operators and drones, unless they were using some sort of entanglement comms.
This.
Makes.
No.
Sense.
How is an electronically controlled fighter without a human pilot any different from one with electronic controls and a human pilot?
Unless you're suggesting future spacecraft won't be entirely fly-by-wire.
Sure it does.
A) Okay, so assuming that EM works on anything in the future is a bit stupid, but having a pilot that isn't affected might serve some advantages over a computer that could get scrambled and such. Besides, notice in dogfighting that your sensors get scrambled and that you can't target. To a computer, that equates to blindness and loss of control. To a human, that equates to annoying loss of aspect lock, but basically full functionality with primaries.
B) This point still makes sense. Fly by wire fails hard if you cut the wire by broadcasting noise to cover any signals that would be going to or from the drone. That's how communication jamming works today.
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The only real advantage, stealthwise, of unmanned ships is the fact that you save on having to heat some kind of living area and having to supply breathing and other needs.
Smaller, faster and more maneuverable ships are harder to hit in a dogfight, where stealth isn't really a factor. Human controlled drones with AI aided evasion and threat detection would present more of a challenge to computer controlled point defense. Sensory interfaces could allow for extra sensors (including point defense targeting data and shipboard target identification systems) to be routed to the human pilots, thus giving them the equivalent of extra sensory perception, which would be far superior to an unquantifiable sense of "intuition"
Also, EMP would present a host of problems for not only your ship-to-ship comms, but your enemies' as well. Hardened onboard AI could keep the drones intact long enough for the pilot interfaces to be re-established. The change in the flight characteristics may even confuse the enemy fighters, thus giving the tactical advantage back to our side.
I agree, which is why I said the main advantage stealthwise :p
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Also, EMP weapons would probably be used much more frequently and to greater effect against drones than against humans, so maybe that serves as a pseudoscience reason for why FS bothers to use manned fighters at all. Plus, if you broadcast a giant wall of EM noise, you'd cut off any communication between mothership operators and drones, unless they were using some sort of entanglement comms.
This.
Makes.
No.
Sense.
How is an electronically controlled fighter without a human pilot any different from one with electronic controls and a human pilot?
Unless you're suggesting future spacecraft won't be entirely fly-by-wire.
Sure it does.
A) Okay, so assuming that EM works on anything in the future is a bit stupid, but having a pilot that isn't affected might serve some advantages over a computer that could get scrambled and such. Besides, notice in dogfighting that your sensors get scrambled and that you can't target. To a computer, that equates to blindness and loss of control. To a human, that equates to annoying loss of aspect lock, but basically full functionality with primaries.
B) This point still makes sense. Fly by wire fails hard if you cut the wire by broadcasting noise to cover any signals that would be going to or from the drone. That's how communication jamming works today.
:lol:
Look up fly-by-wire before you respond to my point. You took it to mean remote piloting. It doesn't.
This is what you missed: the control paths the pilot uses to control the ship will be as electronic as the components of an AI brain. An EMP that can kill one will kill the other. Your living pilot will be locked in a dead ship; your dead AI brain will be locked in a dead ship; same end result.
The only alternative is a purely mechanical backup system but I really just can't see how that'd be practical given the number of electrical systems required for the most basic spacecraft function.
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In real life, fighters like the F/A-18 have a hydraulic backup system. Something like the A-10 is even more redundant. A combat aircraft (or spacecraft for that matter) will not be sent into a high-threat environment without a means of operating in a state of impaired efficiency. And look at deep space in general... it's full of radiation and all sorts-O-nasty. You'd inherently be dealing with forces that would probably be worse than an EMP blast.
I'm not a believer in the "magical force field" as many shows/books/games present, but I do find that a field generator of some type would be needed to protect the crew of the ship from radiation/serious EMP interferance. This would also enable the mass of the ship to be kept much smaller.
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In real life, fighters like the F/A-18 have a hydraulic backup system. Something like the A-10 is even more redundant. A combat aircraft (or spacecraft for that matter) will not be sent into a high-threat environment without a means of operating in a state of impaired efficiency. And look at deep space in general... it's full of radiation and all sorts-O-nasty. You'd inherently be dealing with forces that would probably be worse than an EMP blast.
I'm not a believer in the "magical force field" as many shows/books/games present, but I do find that a field generator of some type would be needed to protect the crew of the ship from radiation/serious EMP interferance. This would also enable the mass of the ship to be kept much smaller.
I cannot imagine any kind of purely mechanical (including hydraulic) backup system that is both practical and that would allow a combat spacecraft to continue functioning after all its electronics were burnt out. I could be wrong, though.
Modern EMP protection is quite sufficient. For radiation in space you need heavy-duty shielding, preferably water or somesuch (you can drink it too.) Force fields prolly wouldn't work since some particles are uncharged.
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Well, a thin layer of gold foil seems to do the job in most occasions, but that could get expensive if we rely on purely terrestrial supplies, after all, Voyager remained functional for years with practically no protection on its electronics at all.
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Yeah, I just meant to protect the crew. Electronics ought to be fine. I should've clarified.
And it's worth remembering that explosions don't generate an EMP in space. You need a specialized EMP weapon.
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Well, a thin layer of gold foil seems to do the job in most occasions, but that could get expensive if we rely on purely terrestrial supplies, after all, Voyager remained functional for years with practically no protection on its electronics at all.
Tinfoil is actually enough to stop dangerous EMP, they use gold to protect the crew against hard radiation.
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That's just lovely :) everyone needs protection sometimes.
Did they use that on the apollo missions?
I bet they were toastz in their pod :)
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Also, EMP weapons would probably be used much more frequently and to greater effect against drones than against humans, so maybe that serves as a pseudoscience reason for why FS bothers to use manned fighters at all. Plus, if you broadcast a giant wall of EM noise, you'd cut off any communication between mothership operators and drones, unless they were using some sort of entanglement comms.
This.
Makes.
No.
Sense.
How is an electronically controlled fighter without a human pilot any different from one with electronic controls and a human pilot?
Unless you're suggesting future spacecraft won't be entirely fly-by-wire.
Sure it does.
A) Okay, so assuming that EM works on anything in the future is a bit stupid, but having a pilot that isn't affected might serve some advantages over a computer that could get scrambled and such. Besides, notice in dogfighting that your sensors get scrambled and that you can't target. To a computer, that equates to blindness and loss of control. To a human, that equates to annoying loss of aspect lock, but basically full functionality with primaries.
B) This point still makes sense. Fly by wire fails hard if you cut the wire by broadcasting noise to cover any signals that would be going to or from the drone. That's how communication jamming works today.
:lol:
Look up fly-by-wire before you respond to my point. You took it to mean remote piloting. It doesn't.
This is what you missed: the control paths the pilot uses to control the ship will be as electronic as the components of an AI brain. An EMP that can kill one will kill the other. Your living pilot will be locked in a dead ship; your dead AI brain will be locked in a dead ship; same end result.
The only alternative is a purely mechanical backup system but I really just can't see how that'd be practical given the number of electrical systems required for the most basic spacecraft function.
Yeah, I totally had the definition of fly-by-wire gimped up in my head. I guess I must blame Perfect Dark for that.
As for EMP effects, we need to clarify whether our discussion is still rooted in the FS universe or not. In the FS universe, as far as I can tell, EMP effects don't "deaden" a ship. I have no clue why it doesn't, but that's the way the game suggests its ships work. Obviously, in a "real" universe with real physics, it'd be trivial to shield up self-sufficient AI in boxes so that EMP can't affect them. Of course, issues surrounding sensors and weapons would arise, but those could probably be dealt with in an age when combat spacecraft are being produced.
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Our discussion hasn't been rooted in FS since we started talking in AU-size distances.
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Yeah, I just meant to protect the crew. Electronics ought to be fine. I should've clarified.
And it's worth remembering that explosions don't generate an EMP in space. You need a specialized EMP weapon.
Well... If the target ship is on (very, very) low orbit above planet with sizable atmosphere and magnetic field you could fire nukes to the planet atmosphere in hopes of generating EMP. Of course even without the EMP it might be better to shoot the nukes at the enemy ship.
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The whole "field idea" is based on the concept of a man-made artificial magnetic field that would divert radiant energy from the ship. This would be similar to the Earth's own field, which protects us in a similar fashion. Because you don't have access to unobtanium, use of 10-ft thick lead-cored walls is not an option for a small, nimble space fighter. The pilot will have redundant protection, but long-term (used relatively-speaking) protection will require a better system, like a field.
Interestingly, some modern aircraft have "shields." The E-4B (a military 747 operated by the USAF) has a field generator which it would use to protect itself from EMP emissions during a nuclear strike scenario, in which it would be flying as an airborne command post.
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The whole "field idea" is based on the concept of a man-made artificial magnetic field that would divert radiant energy from the ship. This would be similar to the Earth's own field, which protects us in a similar fashion. Because you don't have access to unobtanium, use of 10-ft thick lead-cored walls is not an option for a small, nimble space fighter.
Well a magnetic field alone wouldn't do the trick, but a combination of an electrostatic field and a magnetic field would (you'd get both electrons and high-energy nuclei/protons.) However you'd need a lot of advances in high-temperature superconductors (i.e. getting them to work) before that's possible.
And I swear there won't be any small, nimble, one-man fighters in a space war. What possible advantages do they have?
I shall quote!
The notion of a space fighter arises simply from overstretching the analogy between space combat and sea warfare. Aircraft came to dominate over battleships on Earth because they enjoyed speed advantages of orders of magnitude and could move in three dimensions, while surface ships were restricted to two. True, large spacecraft will probably have lower accelerations than small ones, but let’s consider what a space fighter will do for a moment. It would be a small craft designed to deliver missiles to a target out of range of the main fleet and then return to a carrier ship. But why bother returning to the carrier? The fighter is probably nothing more than a glorified chemical-fueled missile anyway, no more sophisticated in principle than the missiles you already expend by the dozen. You can at least double its effective range by replacing the pilot with a computer and turning it into a disposable missile bus (I say at least because the computer will probably mass a lot less than the pilot and the life support systems necessary to sustain him). It may be able to accelerate faster too, since it’s now freed from the restriction of having to not kill the pilot with bone-crushing sustained G forces.
The closest thing one is likely to see to a space fighter in a realistic universe is something like the X-15 DynaSoar. It’s basically a very small one-man armed space shuttle, designed to be lifted into orbit on top of a disposal rocket booster, where it could attack enemy space infrastructure or drop bombs on the planet below and then land like a normal aircraft once it had finished its mission. Such a craft would probably have utility very early in the history of a spacefaring civilization, when it was just starting out.
Glorified missile buses!
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Screw your fields, I have layered aluminium foil. :P
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Although referring to the realistic, I would also like to refer to the more fanciful elements which might still be possible. Manned starfighters are one of them.
After all, this thread is all speculation until someone is able to do something therein. As that's not quite happened, your opinion is only just that. No offense, of course.
And a "field generator" is not just useful for the said starfighter, it's potentially vital for space exploration in the near future. Without such a system (unless a different, better one is found), long-range manned missions might prove harrowing to say the least because of radiation poisoning.
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Although referring to the realistic, I would also like to refer to the more fanciful elements which might still be possible. Manned starfighters are one of them.
After all, this thread is all speculation until someone is able to do something therein. As that's not quite happened, your opinion is only just that.
It is an opinion substantiated by fact. Foresight is certainly not perfect, but this prediction has reasoning to back it.
No offense, of course.
And a "field generator" is not just useful for the said starfighter, it's potentially vital for space exploration in the near future. Without such a system (unless a different, better one is found), long-range manned missions might prove harrowing to say the least because of radiation poisoning.
Water shielding is a good option, as is liquid hydrogen. Magnetic shielding has a number of known problems - this time I'll quote direct from Wikipedia -
Electromagnetic shielding has a number of problems: (1) the fields act in opposite directions on positively and negatively charged particles, so shielding that excludes positively charged galactic cosmic rays will tend to attract negative ions; (2) a very large power supply would be required in order to run the electrostatic and magnetostatic generators, and superconducting materials might have to be used for magnetic coils; (3) the possible field patterns might tend to dump charged particles into one area of the spacecraft.
and I think the most effective solution will probably be a combined suite.
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Water is very massive. Getting that material into space with current or near-future tech would cost... too much.
And then, you have to propell that high mass... blegh.
Use a reactor to power said generator. The reactor is mounted far from the crew module, probably behind it somewhere. If there's a "field dump," hopefully you could engineer a solution to where it dumps behind the crew module and in some place no-one cares about. As understanding on this issue han not been tried-by-fire, I wouldn't rule out that it alone would be incapable of protecting a ship.
And, eh, my X-Wing is still better than your... thing. :p
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Water is very massive. Getting that material into space with current or near-future tech would cost... too much.
Bad news, buddy. Certain elements of a manned space mission need water. I'll give you one guess. And no, transporting it as lox and hydrogen doesn't work; we have something called conservation of mass. (The idea is since you're hauling this stuff you might as well use it as part of the shielding system.)
There's a reason water is consistently cited as a shielding element by NASA and hard SF writers (Baxter, for instance.) Dismissing it out of hand betrays a lack of research on the topic.
Use a reactor to power said generator. The reactor is mounted far from the crew module, probably behind it somewhere. If there's a "field dump," hopefully you could engineer a solution to where it dumps behind the crew module and in some place no-one cares about. As understanding on this issue han not been tried-by-fire, I wouldn't rule out that it alone would be incapable of protecting a ship.
Apparently you aren't reading the posts.
The magnetic system alone is not reliable. Moreover the issue of generating the field at all requires room-temperature semiconductors and a power system of a type not currently available or feasible.
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I certainly am reading the posts. But, if this is going to go anywhere... forward on this particular issue in a sensible manner then I believe I am safe citing that we both need to do more research... and then listing accurately the source of that research. Even a link would do.
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I certainly am reading the posts. But, if this is going to go anywhere... forward on this particular issue in a sensible manner then I believe I am safe citing that we both need to do more research... and then listing accurately the source of that research. Even a link would do.
You want me to cite the fact that space missions need to bring water? That's absurd. As for the rest -
Already done, but if you want more
here (http://www.islandone.org/Settlements/MagShield.html) for a very positive take on emag shields that says they are not yet feasible
well-cited page that states 'water is probably the best radiation shield of all (http://www.adl.gatech.edu/research/tff/radiation_shield.html) (for hopefully self-evident reasons)
and an uncited but nonetheless accurate blurb from Wikipedia, as above:
*
None of these strategies currently provides a method of protection that would be known to be sufficient, while using known engineering principles and conforming to likely limitations on the mass of the payload. The required amount of material shielding would be too heavy to be lifted into space. Electromagnetic shielding has a number of problems: (1) the fields act in opposite directions on positively and negatively charged particles, so shielding that excludes positively charged galactic cosmic rays will tend to attract negative ions; (2) a very large power supply would be required in order to run the electrostatic and magnetostatic generators, and superconducting materials might have to be used for magnetic coils; (3) the possible field patterns might tend to dump charged particles into one area of the spacecraft. Part of the uncertainty is that the effect of human exposure to galactic cosmic rays is poorly known in quantitative terms.
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On top of that, we can look at an extant version of magnetic shield that you previously mentioned, namely the Earth's magnetic field.
This actually channels a fair percentage of high-energy charged particles into the Earth around the poles. You can see the effects of these charged particles impacting into the atmosphere in the far north and far south as Aurora Borealis and Australis.
Thus we can postulate that it's only effective because the poles are nearly to perpendicular to the solar wind, and if it was not then it would be worse than useless.
Finally, we can also look at the behaviour of high-energy charged particles in particle accelerators.
There are some very pretty bubble-chamber pictures, eg:
(http://www.particlephysics.ac.uk/news/picture-of-the-week/picture-archive/tracks-in-a-hydrogen-bubble-chamber/000329_med.jpg)
(Image from Particle Physics UK (http://www.particlephysics.ac.uk/news/picture-of-the-week/picture-archive/tracks-in-a-hydrogen-bubble-chamber.html).)
The spiral tracks are charged particles with relatively low velocity and/or mass compared to their charge, usually created by a collision.
Some spin clockwise and others anticlockwise - this is the difference between positively and negatively charged particles.
Note the fact that they spiral, and the random nature of the final (visible) vector in each spiral.
Finally, there are also many tracks that go straight through and that curve slightly both up and down.
The latter are high-velocity and/or mass compared to their charge. You'll notice that the very strong magnetic field in the chamber has almost no effect on them.
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While it is true that part of the particles end up at the magnetic poles, most of the charged particles actually ends up milling about in the Van Allen radiation belts. Energetic electrons (and positrons, though likely in lesser quantity) form the outer belt, while the inner belt also has protons in it (as well as small amount of heavier charged particles such as alpha particles).
Here's a nice image of simulated Van Allen belts:
(http://upload.wikimedia.org/wikipedia/en/b/b7/Simulated-van-allen-belts.jpg)
By the way, there's actually been plans (http://en.wikipedia.org/wiki/HiVOLT) to remove the Van Allen belts... :nervous:
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By the way, there's actually been plans (http://en.wikipedia.org/wiki/HiVOLT) to remove the Van Allen belts... :nervous:
Kill the Northern Lights? Why the hell would they want to do that?
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No. I just explained that Van Allen belts and Aurora Borealis/Australis are a different thing.
Part of the charged particles ends up hitting the atmosphere near magnetic polar regions during particularly strong solar storms.
Majority of the charged particles in solar wind ends up trapped in Van Allen belts.
Draining Van Allen belts from these charged particles would not reduce the amount of particles hitting the polar region atmosphere during solar storms.
The reason why draining Van Allen belts would be reduced radiation hazards for both crews and equipment of spacecraft. However, I have my doubts about the changes of actually managing to do it.
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Screw your fields, I have layered aluminium foil. :P
Exactly. If aluminum foil can shield my guitar from the dreaded mains hum, surely it can protect an astronaut from some puny cosmic rays. And if that doesn't work he can learn to dodge, or just take it like a man--I don't see what the problem is here, people. :D
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There are also more exotic concepts, like plasma shields (according to old article from New Scientist website (http://"http://www.newscientist.com/article/dn9567-plasma-bubble-could-protect-astronauts-on-mars-trip.html")).
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There are also more exotic concepts, like plasma shields (according to old article from New Scientist website (http://"http://www.newscientist.com/article/dn9567-plasma-bubble-could-protect-astronauts-on-mars-trip.html")).
I believe those fall under the EM shield category...maybe.