"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...

=========
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..."

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

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

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?"

TonyLB wrote: 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?"

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.

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.

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]

timfire wrote: 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.

timfire wrote: 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.

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

Blankshield wrote: 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

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

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.

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.

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
--

I'd like to express my thanks to everyone who commented on this subject and offered their opinions, comments, and even suggestions. I really can't say much more about the SFRPG game I'm working on as it has yet to be announced and I'm under NDA for various components about it. However when we do make the announcement, I'll definitely make sure to include you folks here.

Thanks again!

Kedamono wrote: 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.

Vaxalon wrote: There's a reason why Hollywood doesn't do space combat this way.

Bo-ring!

If I was sitting down at an RPG table, and we had worked up to a space battle, and this was how it worked...

I would shake my head and have a talk with the GM about deprotagonization.

I agree with Johns point here - the failure, IMO, of present RPG systems has been that they seem to think that sitting the character in a gunnery chair and asking them to make a To Hit roll like normal combat is the way to go, and it simply cannot be. The whole point of a complex but rigidly structured system like the command heiracrhy of a ship is to bring all the ships systems to bear with a single decision. Reducing the players to the point of crew who carry out specifically defined and limited roles is what deprotagonises them, not obliging them to act through tools.

Another of my nebulously remembered SF short-stories, By Clarke I think, concerned a form of combat that was rather like the rocket interception games of early console computer gaming. A warhead would drop down toward a target from interplanetary range and would require interception by some sort of countermeasure before it could strike. The dramatically central character operated in cybernetic interface with these drones and expended them against incoming warheads, the tension in the piece, like the game, arising from the opportunity costs of expending time tracking and targeting. As I recall an additional wrinkle in the story was that the headset that allowed access to these gunnery systems contained holographic records of the thoughts and experiences of prior gunners, rendering thew whole exercise rather more personal.

With the application of creative thought to remote and cybernetic systems quite a lot could be achieved IMO that would break out of the deadlocks induced by trying to mirror WW2 style "dogfighting" as some sort of necessary prerequisite to SF warfare. Collapsing the game into one vessel, rendering the separate identities of the characters moot, reinstates the multi-legged beast of the adventuring party joined at the hip.

Kedamono wrote:

Vaxalon wrote: If I was sitting down at an RPG table, and we had worked up to a space battle, and this was how it worked...

I would shake my head and have a talk with the GM about deprotagonization.

Actually Babylon 5 came close. ...

However in the SFRPGs I've played in, Traveler, FTL: 2448, Star Trek, Universe, unless you're the captain of the vessel, your role in space combat is to roll a die when it comes time to shoot at something. ...

This is the reality of SFRPG space combat. As a player, my input into the combat depends on skill sets and whether I'm the commander of the ship. Typically it will be one ship vs one ship and largely played out by those folks into miniature combat. ...

Kedamono wrote:
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.

A favourite article of mine on tactics should be as applicable to space combat as anything else. Essentially, this article characterized the elements of tactics as:

-- Resource Allocation: expenditure of resources to accomplish something;
-- Combine Dissimilar Assets: use units with differing capabilities to achieve something no one unit could do on its own, and compensate for each others' weaknesses;
-- Manoeuvre: the coordination and timing of actions for maximum effect in ways that require skill and planning to accomplish successfully.

With a fourth element that was more a description of preferred results, called "Pace of Decision", or, how many mistakes can you afford to make before you lose?

The essence of making space combat exciting for the players is to ensure they always have something to do. Which leads me, by way of ramble, to a thought that should be ironclad in all SF RPGs:

NEVER DESTROY A SPACESHIP THE CHARACTERS ARE ON IF THEY CAN'T DO ANYTHING TO CHANGE THE OUTCOME OF THE BATTLE. If the PCs are on a ship that goes into combat, and they can't personally make the difference between success and failure, never destroy the ship -- that's a Total Party Kill in the most unfair way imaginable, and unsatisfying from every stance except perhaps the purest of Simulationists. The ship should always be incapacitated and captured, giving the PCs a chance to continue their story.

But back to the idea of what the PCs do aboard a ship. If they're not making the actual tactical and strategic decisions for the vessel, PC actions could include the following:

- Damage control. This ranges from equipment/system repair to human repair, for the medics. This is particularly exciting if the system is crucially important, or involves life-risking activities (cf. Spock in WRATH OF KHAN).

- Hotshotting systems. This covers any roll or series of rolls designed to let a particular equipment/system exceed its normal rated capacity. This can be invaluable in fights where the enemy thinks he knows your ship's rated abilities.

- Control of a particular system that allows for direct personal action. The ranges and speed of most "realistic" space combat prevents old-style hand-eye gunnery, unless it's some kind of brain-computer direct neurolink. Navigation and evasive manoeuvres are excellent PC responsibilities in universes where it's possible. If fire control and ECM are under player control, this too can be an exciting contest of skill between enemy jammers and your own targeting systems.

- Coming up with unorthodox manoeuvres or tactics, particularly if they can contribute knowledge of the enemy that the captain may not have. One reason to put organic lifeforms in charge of space combat is the edge of unpredictability they bring when put up against straight AIs; but this advantage is lost against fellow organics, especially if that organic is the man who knows you inside out because you used to be best friends, and knows you never turn into the sun on your evasions because of a mental block formed back during your first traumatizing battle....

When I was designing Tortuga (A game I plan to get back to), one of the things I thought about was how BORING Space Combat is in most RPG's. Let us face it. Unless you are a pilot, or a gunner, you just simply don't have anything to do during these times. It simply wasn't fun.

While the points about realistic space combat are kinda neat, and I DO love this debate, I am not sure if it's all that useful to RPG design, except to say that in a game that is designed for realism, don't include space battles. ;'D

So, the problem I saw was that players basicly didn't do anything during space combat. Like the Hackers from the Cybergames, once you are in space, it's a one man show. No one really likes that.

So I gave everyone ships.

It is my firm belief that if you are going to have starship combat in a game, and you are going to make it a feature in the game, everyone should participate. Deviding a Capital Ship into little subsections for people to play just does not work. You must give everyone their own little ship. Each little ship can have a function, and it will still be important to protect the Capital Ship that allows people to travel the huge distances between stars without using local transportation abilities. However, each ship will be armed and can do something, and there should be enough possibilities so that each player could have their own unique ship, which can be seen as an extension of ther charecter.

I could go on about why you would engage deep in space, but I'll just let that be for now...

An alternate solution to the quandary of most of the players being out of the action, especially for the examples Kedamono first gave would be for the players to take the role of the ship's AIs.

Each AI would be given a specific responsibility and personality, it would be up to the players to allow the AIs to calculate, innovate and report to the decision making human character/player. The resolution system might involve a degree of accuracy mechanic. For example one AI is tasked with indentifying and tracking targets, the accuracy with which the AI could do this would potentially provide bonuses to the AI tasked with engaging the hostile vessels, and perhaps also the AI tasked with evasion and defense. The degree of success at each task could be transparent to the players, or perhaps more satisfyingly, hidden until the AIs are done reporting to the captain and then put their plans into action.

Plus, it would be fun writing a combat chapter that begins "The standard round is equivalent to 100 picoseconds, enough time for each AI to do one or two major actions..."

I'm new to this forum, and you have the privilege of my first post :P. I have to agree with you on most points. The only exception would be the extreme temperatures involved, and the way space acts as an insulator.

The shuttle and the ISS do not have these problems because the structure loses more heat then is generated. Heaters must be used to keep the crew in comfort. This probably wouldn't be the case in a warship.

Such a powerful propulsion system would most likely have a high-energy capacity. Energy weapons would also be a cause of extreme thermal build up. This transfered into heat, would not just immediately bleed into space. A ship would indeed have to be massive, and filled with heat exchangers to distribute throughout the structure. The crew would find themselves cooking as they sat at their control stations.

I would imagine huge deployable heat sinks, basically "wings in space" ( I know disgusting thought ). The problem would be the exposure you are providing to your enemy. You've just raised a big glowing flag that computers can lock onto easily. Maybe battles will be fought in brief spurts, where ships have to flee to disipate excess heat.

Omen wrote: I'm new to this forum, and you have the privilege of my first post :P. I have to agree with you on most points. The only exception would be the extreme temperatures involved, and the way space acts as an insulator.

The shuttle and the ISS do not have these problems because the structure loses more heat then is generated. Heaters must be used to keep the crew in comfort. This probably wouldn't be the case in a warship.

Such a powerful propulsion system would most likely have a high-energy capacity. Energy weapons would also be a cause of extreme thermal build up. This transfered into heat, would not just immediately bleed into space. A ship would indeed have to be massive, and filled with heat exchangers to distribute throughout the structure. The crew would find themselves cooking as they sat at their control stations.

I would imagine huge deployable heat sinks, basically "wings in space" ( I know disgusting thought ). The problem would be the exposure you are providing to your enemy. You've just raised a big glowing flag that computers can lock onto easily. Maybe battles will be fought in brief spurts, where ships have to flee to disipate excess heat.

"The nuclear pumped laser burns through your crew quarters, roll to dodge."

There's a mess of stuff that I'd argue about in the initial post, but most of you have done it quite nicely. Thanks!

So I'll just respond to one statement:

Kedamono wrote: ...Fusion engines put out a ton of neutrons and the only protection from neutrons is mass and distance...

Keep in mind, also, that capturing those neutrons, and more importantly, their kinetic energy, is one of the things that makes a fusion drive WORK.

Vaxalon wrote: Keep in mind, also, that capturing those neutrons, and more importantly, their kinetic energy, is one of the things that makes a fusion drive WORK.

I won't argue the point further; it's WAY offtopic.

WARNING! MORE OFF TOPIC NONSENSE!

The "Fusion Rocket" model where thrust is applied by expelling the fusion product (superheated helium) itself is a rather silly one: The fusion fuel (deuterium or deuterium/tritium) is, admittedly under extreme pressure in order to cause it to fuse, and the fusion product will be at higher temperature due to the energy relesed by the fusion. However, expelling the helium alone is inefficient since a) helium is fairly light and b) you only get to expell one monatomic helium particle for every two monatomic hydrogen particles which you feed your engine which presupposes a tremendous ammount of feul realtive to the ships mass and a lot of wasted heat. In fact, the only impulse you would see projecting the helium astern would be produced by the compression of your magnetic bottle in the fusion space, I.E. the actual fusion would only serve to produce the EM radiation to feed it's own containment and sustainance.

Wouldn't it be more likely that you would use the heat energy of the helium to evaporate a dense reaction mass like a chunk of iron or something, so as to maximise the gaseous expansion to heat ratio and expell something of sufficient mass to giva a real kick?

In other matters:

I like that you are limiting yourself to sub-relativistic STL travel.

I agree with you that the most likely model for space combat in a newtonian rocket scenario is the type of single-pass fight you described. Unless the aggressor ship had a massively greater capacity to accellerate than the attacked ship, matching velocities in space would require the cooperation of the attacked ship unless the aggressor started out close, at comparable speed, on the same vactor, and dead astern. Otherwise, the attacked ship can just burn as hard as the agressor in the straight path of it's travel and be forever out of reach.

I wouldn't worry about heat so much... The "Refrigeration Laser" concept is sound even based on current tech, and it even provides some abillity to A) burn space-junk in the ships path, B) Burn enemies, or C) supercharge fusion plasma at lower pressures leaving more EM to be used by nifty ships systems.

And no, I don't see any reason why you would want to fight in deep space given this level of tech, unless you suppose an interplanetary war where neither side wishes to sterilize their enemies' planet.

I second the recommendation to check out Attack Vector in detail.

Any effort to make a vector movement space combat game based on "realistic" space movement assumptions that does not use this game as reference source material is a serious mistake IMO.

Hi, I'm new to the Forge, but I've been active on some other gaming forums / lists, most notably sfconsim-l

The sfconsim list has debated most of the aspects of "realistic" space combat a number of times over, and I highly recommend it to those wishing to develop that type of setting. Attack Vector: Tactical was in part developed on that list, and Ken Burnside, the principal creator of the game is active on the list. I also would like to recommend AV:T as an excellent "realistic" space wargame.

I'd like to respond to a few remarks made in this thread, so here goes:

Re: jdagna

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.

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.

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.

The shuttle and the ISS do not have these problems because the structure loses more heat then is generated. Heaters must be used to keep the crew in comfort.

A ship with an active drive would not be a problem, right? Maybe. And maybe not. If you hold a dime out at arms length against the night sky, the area it is blocking off is several times larger than the area this IR telescope can see in high detail. And this high detail is created by scanning that portion of the sky over and over and over, building up layers of detail that a snapshot cannot attain.

acehunter wrote: Kedamono, hope this helps, and I look forward to seeing what product Tri-Tac comes out with. I own and have played Fringeworthy a number of times, and used to have Staking the Night Fantastic (Bureau 13), Incursion and FTL:2448. Nice to see Richard Tucholka still at it after all these years!

-Matt P.

Yeah, that does make combat tricky. I highly recommend taking a look around on sfconsim-l, maybe posting a couple questions on there. The readership on that list spans the whole list of wargamers, specialists in highly technical fields, and just plain smart individuals. Also, you may want to contact the list admin, Chris Weuve. He and Arius have been working on Exordium Tactical, a space wargame in the Exordium universe. (Exordium is a set of 5 SF books written by Sherwood Smith and Dave Trowbridge) In the Exordium universe, there is tactical FTL, so a single ship can attack another ship at the same time from multiple directions by jumping in to 10 light-seconds, firing, then to 7 light-seconds from another direction, firing again 3 seconds after the first time, then to 4 light-seconds and firing again 3 seconds later (6 seconds after the first time). All 3 shots arrive simultaneously from 3 different directions. Great in fiction, confusing as heck in gaming. Chris and Arius have had some success, so they may be a good resource. Google "Chris Weuve" and you'll find both his page for Exordium and for sfconsim-l.

-Matt P.

acehunter wrote: Despite advances in science during the last 400 years, one thing that has not been overthrown is the Second Law of Thermodynamics. The second law creates most of the restrictions that Kedamono describes. Various consequences of the Second Law can be found in the message archive on sfconsim-l. "Realistic" space travel is a lot more restrictive than most people think.

http://www.projectrho.com/rocketstub.html

This is probably the best source of information on space travel and war
in space that I have ever seen. A must for those folks that want to do
realistic SFRPGs.

Neat site. Thanks!
SR
--

While I can't add much to the hard science wonkage, I'm surprised no-one has mentioned Niven & Pournelle's "Mote in Gods Eye / Gripping Hand" books - the second in particular has several large fleet actions of hard science-based non-relativistic combat. Their one handwaving concession is the Anderson Drive and Shield (their FTL system) which itself allows for a pretty nifty take on an interstellar civilisation.

My guess is that, given the fragile nature of us squishies, space combat will be fought primarily by proxy - automated kill vehicles with sophisticated, shielded sensor packages. You save a heck of a lot of mass if you don't need life support and radiation shielding, and you gain acceleration. Unless, of course, your background includes some kind of gravity damping technology. :)