Aircraft Carriers in Space
foreignpolicy.com
foreignpolicy.com
Vernor Vinge's "Marooned in Realtime" has some very interesting space battles, based around the single conceit of "bobbles": impenetrable force shields which essentially separate their contents from the universe (and from time) for a pre-selected length of time. Space battles then become a tricky game of trying to catch your opponent when he's un-bobbled, while at the same time avoiding the bobbled nukes and other weapons he has strewn around when you were last bobbled.
You wouldn't want to be within 20,000kms of such a beast going off, let alone a few hundred metres apart.
And pity whatever poor sucker is on the planet below.
I don't try to rag on it too much for that, though. I just view it as a stepping stone for better space drama.
> For a ship in the water, drag increases as the cube of speed...As your speed increases, your drag increases exponentially...
He's being inconsistent.
I've actually heard this a lot lately -- people will say something is "increasing exponentially" (i.e. has a curve of the form f(x) = k*b^x) when they really mean a much looser condition like "accelerating" (positive second derivative, which might be an exponential curve, but also might be one of many other curves, e.g. any polynomial of degree >= 2 with nonnegative coefficients).
It's almost as bad as people who talk about the "least common denominator," but that's a rant for another post.
And I'm tempted to say that what distinguishes math from most other forms of expression is precision, and if you're not going to be precise, you should avoid blatantly mathematical language.
For example, modern naval warfare, setting aside aircraft even, is of the sort where the combatants generally fire missiles at each other across the horizon (or would be, if there was any significant amount of naval warfare between first world powers). However, in scifi space battles you have warfare which tends to look more like naval battles in the 17th century than anything else. Inaccurate weapons. Point blank ranges. Etc. That sort of warfare was obsolete over a century ago. And even the close cousin in the form of long but still within visual range battleship battles were very rare even during WWII and terribly obsolete after that (the Falklands war being a decent example).
The idea that a laser at a range where the enemy is visible with the naked eye is going to miss is ridiculous. Similarly, the idea that any missile fired would not be guided, or that a guided missile would miss at such close ranges, is equally ridiculous.
But, SciFi isn't about predicting the future so much as it is about setting up a premise with which to tell a story, so I can forgive these shortcomings.
For instance.
http://en.wikipedia.org/wiki/Railgun
"The United States Naval Surface Warfare Center Dahlgren Division demonstrated an 8 MJ rail gun firing 3.2 kg projectiles in October 2006 as a prototype of a 64 MJ weapon to be deployed aboard Navy warships. [ ... ] Such weapons are expected to be powerful enough to do a little more damage than a BGM-109 Tomahawk missile at a fraction of the projectile cost. [ ... ] Its expected performance is a muzzle velocity over 5,800 m/s, accurate enough to hit a 5 metre target over 200 nmi (370 km) away while firing at 10 shots per minute."
I'm sure that these hypothetical railgun projectiles have some method of in-flight correction, but we haven't forgotten how to do trigonometry since WWI. :)
Not all scifi space battles. Just the battles in bad scifi.
Movies seem prone to this. I suspect because making what we think will be realistic space combat visually appealing and easy to follow would be super hard.
Fiction that gets space combat right (off the top of my head) include Stirlings 'Stone Dogs', and Vinge's 'Deepness in the Sky'.
I think that Niven and Pournelle's book The Mote in God's Eye had some interesting ideas. As I recall, space combat involved spherical vessels pouring energy into each others' shields with heavy lasers. The first one to overload the others' shield won.
The first one to overload the others' shield won.
Lasers, nuclear-tipped torpedos, all add to the energy budget. Pent up energy cascades _in_ when your field collapses.
'Brenda' by Larry Niven, set in the CoDo Universe, has as it's backstory the cleanup job after a really large fleet engagement.
"Aircraft carriers in space" makes sense to me. I assume that warping space requires a lot of energy that requires huge reactors that don't fit in small fighters. They would depend on a "mothership" for long range travel.
Highly relativistic missiles, at say 0.98c or more, are effectively impossible to defend against, and massively potent. At that speed a kinetic "warhead" massing only 10 milligrams (perhaps a millimeter in diameter or less) would have an explosive yield of nearly a kiloton. More so, when the missile is 15 million kilometers away (40 times the distance from the Earth to the Moon) the time between when the target detects the missile and impact is only one second.
Even at technology levels far below that level missiles can still remain extremely effective. At long distances (thousands of kilometers away) the missiles would engage in evasive maneuvers to avoid being shot down by speed-of-light weapons. And then at some point they would release a huge number of evenly spatially arranged fragments. At a missile speed of about 40km/s (which is a reasonable estimate for speeds achievable by cutting edge and next generation propulsion technologies today) you get a ratio of warhead mass to TNT equivalent explosive yield of about 190:1 (meaning that a 1 kg impactor yields 190 kg of TNT equivalent in kinetic energy). Which means that a single 500 kg missile could break up into a thousand fragments, each of which is only 3 cm in diameter (if made out of depleted Uranium) and has the kinetic energy punch of nearly 100 kg of explosives. If, for example, we imagine a crewed ship capable of accelerating at, say, 5 gees (~50 m/s^2) and we imagine a fairly small ship that is only about 100 m^2 in cross-section then an attacker could fire a barrage of only 8 such missiles and fragment at a distance of 400 km and have an effective 100% chance of at least one fragment hitting the target. Even with high powered lasers it is no small feat to destroy a 3 meter target at 400 km distance. As the speeds of the missiles go up they become more and more effective and difficult to shoot down.
The other thing is that the faster the missiles go, the harder they are to aim. You lead your enemy's ship and fire the missile, they make a minor course correction in the meantime, and your missile has to detect it and change its vector to match.
Space combat is one of those fun things to discuss where no matter what you suggest, someone will come along and advise you of something you've forgotten.
However, your point about the difficulty of steering a .98c projectile is a little out of place. The point of shooting someone with a weapon that can travel that fast is that you can catch them with their pants down. Such a weapon effectively travels at 50 times the speed of light from the perspective of the target. This is because it is racing any light or signal which would give the target warning of its presence. For example, by the time a ship has had warning that such a projectile is an entire astronomical unit (the distance from the Earth to the Sun, 150 million kilometers) away it will only be about 10 seconds until it hits the ship (the light will take about 8 minutes to travel, but in that time the projectile will cover 98% of that distance, and by the time that light reaches the target the projectile will actually only be a little more than 10 light-seconds away). And such a projectile need only be a few microns in size in order to unleash the explosive power of hundreds of kilos of TNT, so you probably aren't going to detect it at all. So all you have to do is wait until the enemy is sitting in port and you blow their ship up from across the solar system.
Of course, weapons such as that fundamentally change the whole nature of warfare, so speculating about them is problematic.
And it's possible that in the far future we'll be able to warp space, extract massive amounts of zero point energy, and more. In other words, I think it's a cop-out to hand wave about technology for this discussion by saying that it can be done in the future.
"The point of shooting someone with a weapon that can travel that fast is that you can catch them with their pants down."
The problem with this proposal is your target can easily solve this by randomizing the thrust enough, on the assumption that it might be targeted. Suppose you are 1 AU off and fire at where you expect your target to be in 8 minutes. The difference between 0.01g and 0.0101g is 100 meters after 8 minutes, so even a 1% difference in thrust might be enough to miss the ship. But if you're using firing things at 0.99c then your enemy can likely manage better than 0.01g.
You mentioned "all you have to do is wait until the enemy is sitting in port". That "port" is a space station, in orbit. Neptune is 4 hours out. If the station is a 1km sphere, then it only need to move by up to about 20km in any direction to make the odds of being hit be less than 1:100. Neptune is 4 hours out. 20km/4 hours is 0.0002m/s/s or 0.00002g.
For reference, the ISS orbit decays, due to air resistance, by about 90 meters per day. This is easily restored through occasional boosts. Which means that you, as the enemy, are going to need to fire off thousands of these 0.99c bullets in order to hit your target. Where does all of this energy come from?
In any case, with micron sized bullets, you're just going to drill a hole through your target. The exit hole will be pretty much the same as the entrance. Very little of the energy will be deposited into the ship, and it's not likely to take damage anywhere near to the amount of energy you put into trying to hit it.
365 * 24 * 0.0001g = 0.876g for an hour = 70,000 mph worth of acceleration every year.
Everyone says this, which should be a red flag. There's nothing in the physics that precludes this. You just need to redirect your thermal emissions in a direction it doesn't matter and spoof any detectors that could spot you by your occlusion of distant objects. Then it becomes a tactical problem, not a physics one.
If all of your enemy's assets in space are visible, then such stealth is easy. Then you can calculate directions to aim your thermal emissions and spoof the enemy occlusion detectors. So the only way to make stealth difficult in space is to have stealthed sensor platforms.
I think this gives rise to interesting tactical situations.
This also assumes that your enemy doesn't have observation platforms scattered throughout the solar system that can spot you from dozens of different angles.
Exactly. A long, skinny, highly reflective parabola would do it. You'd have to refrigerate the exterior of that, too, of course.
> This also assumes that your enemy doesn't have observation platforms scattered throughout the solar system that can spot you from dozens of different angles.
No, this assumes that you have high confidence that you know where those platforms are, and that you can aim your emissions in a tight enough beam.
Also, don't discount sabotage and espionage. If only one enemy sensor is in a position to see your stealth infiltrators, then there's a single point of failure which is a good target for espionage. When the US military goes in with stealth bombers, they don't just rest on their technological laurels, they also send in elite forces to knock out radar sets. This means that the enemy should maintain double or triple redundant observation platforms. Or does it? What if their observation platforms are stealthed? Then an attacker is playing a guessing game.
Stealth in space won't be perfect, and it will be fraught. However, it will serve a deterrent purpose against other stealth. It will exist because the disadvantage of having no stealth at all leaves open a powerful game changing tool to be exploited by your foe.
But in Millennium Challenge 2002, it was demonstrated that a large attack with small boats and smart tactics, can still be deadly. (http://en.wikipedia.org/wiki/Millennium_Challenge_2002)
What would be a more realistic portrayal? A bunch of automated drones fighting each other. Space even removes a lot of tactical elements. So the one who has the right number of good enough drones wins. That's boring. No heroism, no action, no drama, no suspense.
The sweat and suspense is left in non heroic and to outsiders a bit boring fashion at the engineer's drawing board.
As a case in point, consider the way submarine combat is portrayed.
On the other hand, and unlike here on drag land, accelerating and then shutting down the engines while proceeding at full speed is possible in space.
Maybe the ring of a planet would work. But then the ship is at risk of being damaged by the ice and other things in the ring. And of course there are only few planetary rings compared to the rest of space.
You put the high-power components of the ship at the focus of a very long and narrow paraboloid with a highly reflective interior and a special absorptive and selectively emitting exterior. The whole ship will be refrigerated, with the radiator at the focus of the paraboloid. Then, all you have to do is to aim your thermal emissions in a direction your enemy isn't -- which is easy to do if your enemy doesn't have stealth.
Hence, stealth will exist, but primarily as a deterrent to keep your opponent from using stealth with 100% confidence.
Add in no sound in space, no seeing lasers from the side, battles where you can't visibly see your enemy, ships going 'dead' without much visible going on - there's nowhere to 'sink' if you're catastrophically holed, and vehicular explosions really aren't that common despite what movies would have you believe. If you want 'action', there's not a lot of breadth in a realistic depiction of a space battle.
In realistic space warfare, there might be something entirely different and still visual and aural.
Unfortunately, that might require thinking in new ways, creativity and an open mind. Hence it can not be done in movies that only recycle ideas.
b) Interestingly enough, this is probably the most dominant form of naval warfare in the last decade or so, due to the increase in piracy off the horn of Africa. Of course, this isn't the way things go down when warships are on both sides.
So true. It pains me how often I see SciFi, particularly older works, judged on the in/accuracy of "predictions".
H.G. Wells wrote a book called "Clipper In The Clouds" and it also used navy themes influencing how people thought it would go.
http://www.dancarlin.com/disp.php/hharchive/Show-42---(BLITZ...
It explores the history of air power as well, including the massively inflated early expectations that sound basically like modern nuclear war.
In the future, aircraft carriers will be space ships, not naval ships. The aircraft will fly down from the carrier to conventional enemy airspace, then return to the carrier in space.
From what I know, that would actually solve some of the problems that current aircraft carriers are coming up against as enemy defense systems are currently evolving. I assume it would introduce some major new problems too, but I haven't checked the math. Anyway, it's a cool idea for a sci-fi story.
Nor is getting to "ground" from orbit free. You need to cancel your orbital velocity, or most of it, in order to manage a sustainable atmospheric re-entry. Sure, you can use parachutes later in the process, but they don't work in vacuum.
As for the 'carriers in space' thing that he thinks is incorrect, it's at odds with the rest of what he says. While he does defend his point with a function of sea carriers providing the interface between sea and air, that's not all they do. The aircraft carrier doesn't function as a battleship, the fighter aircraft do. The carrier functions as a support ship, an auxilliary, to the craft doing the fighting. Same in space. The large support carrier gets to hold the supplies, living quarters, extra fuel and so on, and the small craft contain the bare necessities for waging battle without having to lug around needless support slowing them down (remember also he talks of issues regarding mass and agility). I'm not saying that it's viable, just that there's more to a carrier than 'sea/air interface'.
If we could launch single air planes from tiny cruisers efficiently, there would no carriers and naval strategy would be completely different. There aren't similar economies of scale for supplies, living quarters, extra fuel, and so on.
There are - carriers have things like post offices and cinemas, which you don't get on smaller craft.
http://www.frontierastro.co.uk/Elite/eliteplus.html
Also an OpenGL version of Frontier exists, base on the disassembled Atari ST release
And it also means we failed to fix that.
I'm serious.
The strategy of parasitism is the one strategy that has been around almost since the beginning of life on Earth. Any evolved system which is as efficient as possible is necessarily vulnerable to parasites and so constantly changing and adapting to repel parasites is considered to be one of the most important -- possibly the most important -- of evolutionary drivers.
But parasitical behaviour is fractal. It doesn't just happen to organisms, it happens in social structures too. Sociopathology is a high successful minority strategy and so will always handsomely reward whoever rediscovers it once it has been defeated.
And just as you can see the whole history of sexual reproduction as a response to parasitic organisms, you can see the rise and elaboration of civilisation as a response to parasitic social behaviour.
It will never go away.
(There's also the fact that we evolved as predators, and predators basically live in a strictly zero-sum world vs other members of their own species -- which has irreversibly shaped us to see things in those terms).