Realistic Space Battles (Long)

[Kedamono]

"Captain, possible hostile craft detected," Battle Computer AI Hans said.

"Thank you Hans, put him up on the tank," said Captain Bridger. The holotank shimmered and then displayed the vector tracks of all known objects in near space. Hans cleared out the vectors for other ships and other bodies, leaving a glowing green trace for the Cruiser Achilles. It was bright green up to the dot that represented the ship, and a dim green for where the Achilles would be in the future.

A glowing red vector appeared higher up in the tank, but the future vector cone for that track intersected the dimmer green track for the Achilles. The vector cone represented all possible positions for the other ship, and most of them were near the Achilles.

"Do we have an ident on that ship yet?" Bridger asked.

"Nyet comrade Captain," said the Achilles' primary AI, Boris. "The drive plume spectral lines are not in the database. However, the primary lines are indicative of a Vesh design."

Bridger swore. Vesh ships were living creatures and packed a wallop. And they traveled in packs...

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Let's talk about ship to ship combat in space. First off, erase from your mind every, and I mean every, Hollywood depiction of spaceborn combat you have ever seen. Hollywood's version of space combat has much to do with reality as a Road Runner cartoon does with realistic physics.

NO space fighters.
NO plucky characters manning the gun turrets.
NO space ships making turns like battleships in the ocean.

None of that.

Events happen both very slowly and very fast at the same time. At the speeds most ships in SFRPGs travel, encounter time with another ship is measured in seconds. Most ships in SFRPGs move at 14% the speed of light, or about 26,000 miles per second. Not hour, per second. Blink and you miss it.

This means that for the most part, the primary role for humans in space combat is identification of targets, and then only when the targets are at a distance. And even then you'll be heavily dependent on the ship's computer for targeting information and data. And you'll never see the other ship unless you use your ship's telescope, and then you may only see a speck of light.

Space combat boils down to waiting till you're in a position to deploy your weapons, and then pray your computer is faster than their computer.


=========

Vector lines for the ship's missiles traced out in snaking cones. The Vesh ship was one light minute out, and was capable of doing 25% light if pressed. Currently they were cruising at 15% light. The two ships would meet in three minutes thirty seconds. Bridger had two minutes to make up his mind before ordering the launch of the Achilles' missiles.

"If it is a Vesh patrol boat," he said out loud, "what kind of weapons does he have?"

"He will have plasma guns, possibly missiles, and lasers," said Hans. "How many of each, I do not know."

"Give me some possible tracks based on known data."

Red cones snaked out from the Vesh ship's current course and intersected the Achilles's track before the Achilles's own missiles intersected the Vesh's course.

"OK. Emily? Plot us an evasive course and keep us out of range, engage now!"

"Sure suhgar!" the navigation AI said.

"Prepare for evasive maneuvers!" intoned Boris over the ship's com.

The future track for the Achilles became a cone and Emily began plotting random course changes within the operating parameters of the ship. Bridger sat down and strapped in. He could hear every loose item in the ship hitting the floor and rolling around...

==========


As for space fighters... Fighters are primarily a means to deliver ordinance on a target. With better missile guidance, even AI guidance, missiles will replace fighters as a means of delivering ordinance to the target. And barring "magic tech", AI guided missiles can pull 50G turns and maneuvers that would turn humans into mush. Humans vs Cylons? Cylons win.

As for weapons, we still have the usual assortment: Lasers, Missiles, Particle Beam weapons and the like. The are still effective, but have different limitations.

Current lasers have a maximum range of 310 miles. At that distance the laser beam is 26 yards wide, but still able to deliver enough energy after 1 to 10 seconds to destroy the target. In most SFRPGs, military lasers will diverge to 26 yards wide at a range of 30,000 miles. It's a close range weapon, where close range is defined as 0 to 15,000 miles. Only computers are fast enough to direct and fire lasers at incoming targets. These lasers are pulsed, since you can get higher energy densities for short bursts than with a continuous beam.

Missiles will be highly evolved kamikaze robotic spacecraft, capable of delivering its warhead to the target at high rates of speed, potentially around 20% to 25% the speed of light. The warhead will be entirely kinetic, at those speeds anything the missile hits will be toast. The warhead may consist of baseball sized ball bearings and the warhead comes apart 1 second before impact, spreading the ball bearings to an area five times the width of the missile, doing more damage over a larger area.

Particle Weapons will typically be charged particles fired at targets at short to medium range, as it is possible to encase them in a magnetic bubble, reducing their spread.

Kinetic Energy weapons are short to long range, especially if you have a good prediction on where your target is going to be. Some can get up to relativistic speeds, + 50%, but when fired, the ship will move in the opposite direction.

Pulling behind a ship or trying to match vectors will result in the lead ship dumping kinetic kill devices in front of you.


==========

Two minutes later the Vesh ship's track cone began collapsing as the Vesh saw and began reacting to the maneuvers the Achilles was pulling. It was decision time for Captain Bridger. It was definite, the Vesh was targeting the Achilles. "Launch missiles!"

Linear accelerators aimed and then kicked out the four missiles tasked with job of taking out the Vesh ship. As soon as they were far enough away, their drives fired up and they rode plumes of fusing hydrogen plasma.

::Blue 1:: I have target vector. Transmitting.

::Blue 2:: Roger. Vectoring on future position 0.1 secs.

::Blue 3:: Roger. Vectoring on future position 0.2 secs.

::Blue 4:: Roger. Vectoring on future position 0.3 secs.

The kinetic killguns on the Achilles warmed up and began scanning the skies for incoming targets, as well as the targeting data from the ship's main sensors.

At two minutes, 15 seconds, six vectors left the track for the Vesh ship. Bridger swore, they launched before the Achilles did. He prayed his target prediction systems was better than the Vesh's...

==========


What ties this all together is that if you are running a realistic SF game, mass is a premium. Most spaceships will be built as light as possible, which means no armor other than asteroidal armor on the leading and trailing portions of the ship. Ships will consist of 70% fuel tanks, 30% everything else.

And of that 30%, 10% of the ship's mass will be dedicated to the engine shield. Fusion engines put out a ton of neutrons and the only protection from neutrons is mass and distance. So ships will be at least a mile long if not longer. Lifesystem at one end, engines at the other. No engine room, at least not while the engines are running, and even then the engines are going to be radioactive.

To optimize fuel usage, you do a lot of burn and coast from one place to another. So a trip to Mars from Earth may take year or longer depending on where they are in relation to each other.

This is why most "realistic" SFRPGs tend to bend physics, if not twist it out of shape. Spending a year or two coasting out to the jump point does not make for an exciting game.


========

At the last instant, almost literally, Emily swung the Achilles around and pointed the drives at the incoming missiles and did a dirty burn. Superheated plasma spread out and the EMP wave momentarily blinded the missiles, long enough for the shielded killguns to get a track and fire, filling the space ahead of the missiles with 2 cm ball bearings moving at 30% light.

Five missiles met their ends 12,000 miles from the Achilles. The sixth got through and impacted in the superstructure between the drive section and the rest of the ship. Metal twisted, buckled under the impact, but the Achilles was a warship, and had redundant supports. She'd survive.

The Vesh ship blossomed as Blue 3 and Blue 4 intercepted it.

Emily kept up the maneuvers for another minute just in case Vesh had fired other weapons, but the all clear was called when the maximum engagement time interval expired.

"Damage report!" ordered Bridger.

"The number one strut assemble is gone, with minor damage to the other three," said Boris. "We will have to return to base to effect repairs. It is more than my repair bots can handle."

"Right. Great. Emily, can we get a vector back to Trojan base?" Bridger asked.

"We burned a bit of fuel honey," Emily replied, "but we can do a boost and coast. It will take a week to get to Trojan base suhgar."

"Thanks Emily, plot us a B&C and engage when ready. Boris, contact the Hermes and let April know what happened..."

[TonyLB]

Why would anyone in a sensible universe be engaged in space combat?  What are they fighting over?

[Kedamono]

Why would anyone in a sensible universe be engaged in space combat?  What are they fighting over?

To be honest, why do we fight now? The list is an arm long. Besides, it is expected to happen in SFRPGs as a starship moving at 15% the speed of light makes a great kamikaze weapon...

Unfortunately the concept of enlightened alien races is basically a fallacy. It is doubtful any race we encounter will be any better at controlling their base urges than we are. And even if we don't encounter aliens, humans are feisty enough to throw down over a world or resources.

[TonyLB]

Yes, but... well, we fight over resources much of the time, or to control territory.  Space is, almost by definition, the place where there are no resources, and there is too much territory to ever control.

But I guess, in asking "why do they fight?", that I'm really trying to get at "What will the PCs be doing in this system?"

[Kedamono]

Yes, but... well, we fight over resources much of the time, or to control territory.  Space is, almost by definition, the place where there are no resources, and there is too much territory to ever control.

But I guess, in asking "why do they fight?", that I'm really trying to get at "What will the PCs be doing in this system?"

Well as you can see in the example I worked up, nothing.

Only the captain/bridge crew will have anything to do, and depending on the circumstances, only the captain will make the final decision. That's about the only thing the captain and bridge crew can do is make decisions on tactics, maneuvers, and targets, but the actual implementation of these decisions will be left up to the ship's AIs.

In my example, I purposely made the AIs subservient to the Captain, they can only act on there own if its impractical or impossible to ask permission.

The actual combat portion of the example probably took less than 5 seconds in reality, and the humans could not act fast enough to do what the Battle AI did.

In the game I envision I don't see space battles being the primary focus of the game. Instead I see exploration, trade, commerce, interpersonal relations take center stage. I want to make space combat both boring and incredibly dangerous at the same time. And using reality is the best method.

[jdagna]

A bunch of comments/questions:

You say that most ships in SF travel at 14% of light.  Is this based on the assumption that you have no FTL capability?  And why 14%, since higher fractions just require more fuel?

Why do you assume short burns and long coasting?  A 2 G acceleration requires 4 times the energy of a 1 G burn for the same unit of time.  If you burn at 1 G for twice as long, you've used half the energy, for the same final speed.  If you burn at .01 G, you've used 1/40,000th the energy in the same time, and only need to burn for 200 times as long (thus, your total energy usage to match speed is 1/200th).  This is why NASA is so interested in engines that burn at only 1-2% of G for long-distance travel.

If ships are traveling at low to no G, at 14% of light, then humans are basically banned from space travel altogether, aren't they?  A short trip would take 30+ years and humans have serious physiological problems after only a few months without gravity.

Additionally, with such good and fast robots, why would a human do anything at all?  Perhaps your game should treat humans as biological baggage and focus on robotic PCs?

Why so much fuel?  if you could do a perfect energy-to-movement conversion, a ship like you're talking about could get by on a few thousand tons of liquid hydrogen which would be well under 1% of the ship size.  Anti-matter would require 1/1000 of that space, but would be more dangerous in case of damage.  Solar sails could provide acceleration for free.  

In any event, I can't imagine interstellar sub-light travel being possible without a "reactionless" drive.  Using space-shuttle energy conversion rates, you couldn't get to another star with any amount of fuel.

Also, you seem to make two mistakes in talking about speed.  

For one thing, combat velocities care only about the relative speed of the ships.  So if two ships fight at 26,000 mps, the relative velocity could be anywhere between 52,000 mps (if they're heading at each other) or 0 mps (if they're traveling along the same course).  At a relative speed of 0, battleship-like maneuvers DO make sense.  There's a good reason to match velocity as well - battles are always about resources, and you can't take resources unless you can match speed.

The second thing is that ships have to slow down.  At 15% of c, doing a 1 G decel, it would take you about two months to reach a relative stop.  So, as ships approach planets, they'll be moving much slower.  Planets are where the resources are, and even if you just ambush ships instead of attacking planets directly, the speeds should be lower - a pirate wants to actually take the resources from the ship he kills, after all.

As for fighters, you make a very good point.  However, what's the difference between a fighter a complex MERV?  In other words, you could use a robot-controlled vehicle that could deploy a number of smaller weapons near the target, which would reduce the weight of each individual weapon (they don't need as much fuel individually).

When it comes to kinetic kill, you have to remember relative velocity.  A missile at 14% of c is certainly lethal compared to most warheads, but you're banking your entire offensive potential on relative speed.  Thus, you can kill something easily if it's heading toward you, but if it comes up from behind with an arsenal of nukes, you're defenseless.  You can solve this easily enough by having removable warheads - stick lead in when the relative velocities are high, and use nukes when they're low.  

And, dropping kinetic weapons behind at a ship trying to match velocities won't work any better than firing missiles at it, precisely because the velocities are already similar.  Don't forget that a ship matching velocities doesn't have to be behind you - it could just as easily be traveling parallel or even in front of you.

You talk about kinetic weapons changing the ship's velocity.  This change in velocity is going to be very minimal - if you're talking about 1 mile ship, it would take a huge projectile at a very high speed to even notice the change.  In game terms, I think you can ignore it.

[DulothS]

By my own Sci-FI d20 RPG:

Most ships planning on combat travel at very slow speeds for preciesly the reasons you mentioned; the faster your moving relative to your enemy, the more likely you are to take damage. And the faster your moving, the less likely it is you can stop and move another direction, or even stop at all, rather than running right into the enemy.

If your targets are enemy ships, you want to slow down to match speeds so that you can dodge their attacks more effectively, as well as so that when your finally in range, you can actually keep firing untill you hit the enemy instead of making a single firing pass, and then be forced to slow down to a complete stop, turn around, and never catch the enemy if they should survive; the only enemies you make a high-speed run against are ones vastly superior to yourself, immobilized ones which you can take your time in killing and so make several leisurely passes, or ones which you can take down in a single blow.

AIs can be subverted, easily; any race which has ever had problems with rogue AIs or programmers creating AIs with their own intentions in mind will limit exactly how much authority they have in ship operations. In one of my Sci-Fi settings, AI-controlled ships are illegal because the first colony ship; sent to Alpha Centauri; had an AI on it that, due to a 'practical joke' a computer hacker played on one of the main leaders of the colony, wiped out the colony and came back to deal some destruction here in Sol before being stopped. As complex as AIs are, its impossible to exactly know how any given extra bit of programming would effect them, or even if it would effect them the same way if applied twice; thus, living human beings are in controll of most ships, and their reflexes are limited by this.

Mind you; in the 'future' of that setting, they developed implants which allowed direct ship to pilot brain interface, and even purely organic ships which acted as a pilot's 'body' and you simply inserted his brain into a casing. These had reaction speeds as high as those of AI-driven ships.

Another big thing on Detection speeds; Einstein theorized that a gravitic change would take effect immediately, at FTL speeds. Other scientists disagree, but in general most scientists agree that, at least by the time you reach the quantum level, some particles and means of detection move at FTL speeds; there have even been successfull experiments in teleporting objects before. Thus, what the more advanced scanners are likely to pick up is the real, current location of a target rather than where it appears to be.

Acceleration/Decceleration:
While its best to go at rather slow speeds for most (Not all!; quite certainly some people would fight in exactly the way you mentioned) combats, for long-distance journeys, the optimum possibiliy is to accelerate the entire first half, and deccelerate the entire last half, at whatever the best fraction of acceleration you can get without expending your fuel reserves might be. If you have fuel systems so efficient you can maintain 1G both ways, this resolves huge numbers of issues for a human-crewed vessel; otherwise, some form of cryogenics is necesary, and limiting 'Waking' time spent at less than 1G to under a day each journey would be best.

[timfire]

First, is this for an actual game you're working on, or is this just a general discussion on 'realistic space combat'? What type of game is it? Is it a standard RPG, or is this wargame of sorts? If its not for an actual game, well, the Indie forum is suppose to be reserved for actual projects in development. Don't worry, just remember it for next time.

Anyway, though I'm not an expert in SF in any way, I've thought that the key in defense in such a situation would be to create a perimeter around the ship with sentinel vechicles - either manned or computerized - that would protect the ship from afar. Basically, keep the bad guys far away enough that they can't use their big guns on the main ship.

[edit] Funny the difference one word makes. [/edit]

[Kedamono]

First, is this for an actual game you're working on, or is this just a general discussion on 'realistic space combat'? What type of game is it? Is it a standard RPG, or is this wargame of sorts? If its not for an actual game, well, the Indie forum is suppose to be reserved for actual projects in development. Don't worry, just remember it for next time.

Sorry, I should have said it's for a standard RPG. I'm part of a design team for Tri Tac Games, one of the granddaddies of indie RPGs. I really can't say more, NDA, and all that. But I can talk about the bits that bother me.

Anyway, though I'm not an expert in SF in any way, I've thought that the key in defense in such a situation would be to create a perimeter around the ship with sentinel vechicles - either manned or computerized - that would protect the ship from afar. Basically, keep the bad guys far away enough that they use their big guns on the main ship.

That's fine if your in the coast phase of your trip, but if you're under power, the smaller ships cannot keep up due to a lack of fuel and reaction mass. If you're building the sentinels big enough to keep up with the main ship, you've pretty much built a full fledge space ship.

And then you raise the question of "afar" or "far enough away". How far is "far enough away"? A horde of kinetic kill weapons really don't care how many little ships you have out in front of your main ship, they just reduce the amount of damage your main ship takes.

[Blankshield]

Kedamo,

Can I suggest that you check out Ad astra Games, in particular Attack Vector: Tactical?

It's a miniatures based space combat game that takes science and reality strongly into account, and deals with many of the standard tropes of sci fi in much the same fashion you do: by dismissing them.  What it does do is keep humans in the picture quite plausibly, which is of primary interest for an RPG, I would think.

Obligatory Disclaimer: I worked on the game quite a bit and was on the testing crew.

James

[Kedamono]

Kedamo,

Can I suggest that you check out Ad astra Games, in particular Attack Vector: Tactical?

It's a miniatures based space combat game that takes science and reality strongly into account, and deals with many of the standard tropes of sci fi in much the same fashion you do: by dismissing them.  What it does do is keep humans in the picture quite plausibly, which is of primary interest for an RPG, I would think.

Obligatory Disclaimer: I worked on the game quite a bit and was on the testing crew.

James

Thanks James, I've looked at Attack Vector: Tactical. My POV comes from that great space game, Triplanetary by GDW: http://www.boardgamegeek.com/game/3637 and Laplace, Newton & Lagrange from BoneGames http://www.bonegames.com/games/lnl.html

I'll take a closer look at AVT and see if it does meet my needs.

[Bankuei]

Hi folks,

Also check out the new version of Albedo, it pretty much has been solid on hard sci-fi space combat.  Though it does include jump drives, pretty much combat is handled by AI ACVs that work as offense, defense, and scout ships.  Between the pilots and the AI, they work out some likely plans for offense/defense, the ACVs spend anywhere from hours to a couple of months getting to the targets(accelerated at about 30 G's), and everyone straps in and prays.  Within a few seconds, combat is over.

System-wise, Albedo doesn't include any specific vehicle rules for this, but the description is well worth it.

Chris

[Sydney Freedberg]

Or you could use a variant of Contracycle's very abstract "Sword of Damocles" mechanic, which boils down to "make one mistake and you're dead." Which seems in keeping with the kind of combat you're describing here.

[contracycle]

Hmm, I hadn't quite thought of that application but it makes sense.

I'd also just like to remark I'm in almost total agreement with Kedamono's model here; matching velocities seems counter-productive and I just cannot see that happening; far better to drop kinetics on the target and come back later to scan the wreckage.  Yes I agree this pretty much rules out conventional piracy but thats just too bad IMO.  There is also one good reason for putting pilots in fighters that has not been mentioned: an enclosed information system.  Remote control systems will be susceptible to jamming, interference and delays, but if you put a pilot in the cockpit you can harden the shell against hostile ECM/ECCM.

[Rob Carriere]

John,
You speak of realistic, but what exactly do you mean? We do not currently have space combat capability, nor do we know anybody who has, not even by rumor. So, anything anybody writes about space combat is going to be pure speculation.

And the history of technology shows one thing very clearly, very consistently: that speculation will be wrong. Absolutely, positively wrong. Count on it.

So the question becomes, in what way do you want to be wrong? Your write-up suggests, but doesn't state explicitly, that you want to be wrong in the Gernsbackian way: everything that happens has be explainable with present-day science as constrained by the notions of present-day technology. This is, of course, completely unrealistic. By the time technology has advanced enough to do this sort of thing, the technological perspective will certainly have changed and the science quite probably. Note that there is nothing wrong with any of this. If you have to be wrong anyhow, you might as well be wrong in a way that you enjoy and Gernsback-style speculation can be great fun.

So, going by the Gernsback rules, I see a number of holes in your set-up. You probably have answers for a lot of these, but they aren't specified in your write-up.

First, you should specify the boundary conditions. Are we talking interplanetary capability here, or interstellar? That's going to make a major difference in tactics and strategy (You literally have years to plan the defense for an STL interstellar assault unless they're coming in at high c-fractional and do not slow down--a rather risky strategy.)

Is the drive technology nuclear fusion (not very plausible with the speeds and maneuver rates you suggest) or something better, say matter/anti-matter reaction (which would eliminate the boost-and-coast need)?

Also, what is that human doing on that ship? Read Arthur Clarke's short story "Superiority" (which was required reading at MIT in the 50s). The human captain is a direct analogon for the vacuum-tube battle computer in the story. Is there any reason to believe that the captain will be exploited any less efficiently by the enemy?

In line with that, as somebody has already pointed out, you have an acceleration problem. Reaching the velocities you mention takes over a month at constant 1 G. Even at 100 G (hope you ditched that captain) you're still doing 8 hours. A railgun that can fire stuff at even 1% of these speeds would have to be made from unobtainium, as would the stuff fired (Say a 1000 m railgun accelerates the missile to 300 km/s, makes an acceleration of 4.5 million gravities--so never mind the neutron radiation from the drive, the magnetic fields from the railgun will kill everybody, biological or electronic, on board, right before they rip the ship apart.)

Finally, why on Earth are these ships attacking each other? No one does naval actions for the sheer exhilaration of it. Earth's sea-navies are, depending on the historical period you choose, mostly about controlling shipping and/or projecting force on land. A space navy of the type you describe could perform these tasks from great distance. A c-fractional kinetic kill weapon with terminal targeting capability could be fired all the way across the solar system, so why would any naval vessel want to get up close and personal? Wouldn't it be much more logical to suppose each side's planet(s) had a number of orbiting bases with missile capabilities? And would anybody actually start a war, or would there be a cold-war style stand-off? The weapons you describe are quite capable of devastating a world, so you have a situation with MAD.

An alternative to the Gernsback approach, which is probably superior given that you are designing a game and not writing a science piece for an SF magazine, is starting out by deciding what type of space combat you want and then twiddling the science and technology to match that vision. Larry Niven has a piece about the design of the technology in The Mote in God's Eye that might be interesting reading. His, or rather Jerry Pournelle's, technology is of course largely "magic", but the sort of reasoning they went through should be directly transferable to your situation. They basically ask what space combat should be like (exciting but survivable, in their case), then ask what sort of conditions you need to get there (relative speeds, offense to defense effectiveness, etc) and finally design a technology with the required properties.

SR
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