Space Chases

[hix]

How to use the existing chase rules in the black void of space, some ramblings:

1. There's no top speed in space, so the speed stat is not needed. Accel is king, perhaps mitigated by the mass carried if you want to get that crunchy.

2. No friction and preservation of momentum means no turning rules are needed, but the "moves" table in the chase section would be altered.

3. The Handling stat should determine the "class" of ship, and keep them in line performance-wise.

4. The abstract ranges are perfect for space battles, as the distances are usually too weird to imagine.

What else ya got?

[Ian Absentia]

5) Effects on crew from acceleration/deceleration need to be accounted for (even if hand-waved with shipboard artificial gravity).

6) Potential effects of momentum on ship-to-ship weapons.  Light-speed weapons (i.e., lasers) may not be practically affected by movement, but projectile weapons (missiles, cannon, rail-guns, etc.) will be.

Aw, now you have me all nostalgic for Mayday and Triplanetary!

!i!

[hix]

18 minutes ago, Ian Absentia said:

effects of momentum

yeah, I have used Weapon Range to account for this. Of course the tungsten or iron ball fired by the railgun will continue moving indefinitely in the void, but the relatively low speed means it's only accurate within a certain range for a moving target.

Missiles are another can of worms, still going back and forth on whether they should have movement and a presence on the battlemap, or to just keep it simple as an attack that can be dodged by the pilot.

[ThornPlutonius]

"Turning" should still be considered, even if only as a vector change.  Accelleration/decelleration would come into play as a means for changing vector.  So, the mass of the vessel would factor into how quickly they can change orientation prior to changing vector.  E.g., the Millennium Falcon can change vector much more quickly than an Imperial Cruiser, perhaps allowing it to escape the chase by "out turning" its adversary.   So, I guess your "handling" stat covers that.  So, never mind.  Don't read this post.

Edited December 4, 2020 by ThornPlutonius

[Ian Absentia]

1 hour ago, hix said:

Of course the tungsten or iron ball fired by the railgun will continue moving indefinitely in the void, but the relatively low speed means it's only accurate within a certain range for a moving target.

Or if matching ship speed and vector.  Maneuver the two ships to the point where they're stationary relative to one another and blast away.  Of course, sauce for the goose...so match, fire, and disengage as quickly as possible.

I was just cursing how much Noble Knight was charging for a copy of Mayday, but then I discovered that DriveThruRPG is selling a PDF version of the game for $19.99.

!i!

[hix]

2 minutes ago, Ian Absentia said:

matching ship speed and vector

matching speed is a matter of ship positioning and moves in the Chase system to stay within a certain Range

matching V sounds like a white-knuckle mano-a-mano dogfighter pilot affair, and should be settled with an opposed Piloting roll. I can imagine a series of opposed Pilot checks determining attack and defense initiative in a fluid way. This sounds very interesting.

Opposed checks between competent parties tends to end in a tie with both succeeding. Would this be the "even odds" situation, giving neither bonus nor penalty?

[Ian Absentia]

26 minutes ago, hix said:

matching V sounds like a white-knuckle mano-a-mano dogfighter pilot affair, and should be settled with an opposed Piloting roll. I can imagine a series of opposed Pilot checks determining attack and defense initiative in a fluid way. This sounds very interesting.

Opposed checks between competent parties tends to end in a tie with both succeeding. Would this be the "even odds" situation, giving neither bonus nor penalty?

Matching vector (and denying it) is going to be a highly predictive affair, something like fencing, I imagine.

!i!

[Mugen]

When changing direction, centrifugal "force" might be a concern for the pilot, as it's proportional to the speed, squared.

[Kloster]

But inversely proportional to the radius, which is quite often in space measured in dozens of kilometers. I'm not sure the game is worth this level of accuracy.

[Mugen]

17 hours ago, Kloster said:

But inversely proportional to the radius, which is quite often in space measured in dozens of kilometers. I'm not sure the game is worth this level of accuracy.

Well, again, speed is squared in the formula.

If your speed is equal to Earth's Escape Velocity (11000 m/s), you'll have to divide 121 million by radius to get resulting centrifugal acceleration. That's a lot of Gs to absorb/compensate.

[Kloster]

10 hours ago, Mugen said:

Well, again, speed is squared in the formula.

If your speed is equal to Earth's Escape Velocity (11000 m/s), you'll have to divide 121 million by radius to get resulting centrifugal acceleration. That's a lot of Gs to absorb/compensate.

That's right. Even divided by 1 million meters, that's quite a big number. But if you have the tech to perform a U turn at 11 km/s, you also have the tech to absorb the Gs. What I said is that I don't think this level of accuracy is needed.

[Questbird]

This discussion assumes space combat would be like aerial dogfights -- the Star Wars or Elite:Dangerous model. I think it would likely be more like submarine combat, fought at distances where the combatants can't see each other. Half the battle would be working out where your opponent was with sensors and/or guesswork, then your computers and theirs would activate the energy beams and someone would get fried. It's a bit less fun though.

[hix]

58 minutes ago, Questbird said:

distances where the combatants can't see each other

alright let's make some wild assumptions:

Lasers do damage with heat, needing contact over duration to do significant burn. So you have to be close to keep contact.

Railguns do instant kinetic damage, but because of their relatively slow speed have less range.

Missiles/torpedoes do instant damage but have range limited by fuel. they can also be detected, so you can't shoot from too far away.

what else ya got?

[Lloyd Dupont]

I plan to do like Master of Orion... mm.. not really any chases there.. if you can survive 2~3 round, you can engage the warp drive!

But I guess this was a different sort of question.... for simplicity sake one could use round to round relative velocity on the map. which suddenly make the map (kind of) the usual square movement map, like for character.
The only difference is what happen in case of impact with a large immobile object (like an asteroid...)

Other than that, in space there isn't much of a chase... either you have a faster drive.. and you slowly (or quickly?) get away. or you don't and, at best, if you are more mobile, you can circle around your pursuer...

 

Edited December 16, 2020 by Lloyd Dupont

[Mugen]

3 hours ago, hix said:

alright let's make some wild assumptions:

Lasers do damage with heat, needing contact over duration to do significant burn. So you have to be close to keep contact.

Railguns do instant kinetic damage, but because of their relatively slow speed have less range.

Missiles/torpedoes do instant damage but have range limited by fuel. they can also be detected, so you can't shoot from too far away.

what else ya got?

Plasma weapons ?

[Mugen]

3 hours ago, Lloyd Dupont said:

But I guess this was a different sort of question.... for simplicity sake one could use round to round relative velocity on the map. which suddenly make the map (kind of) the usual square movement map, like for character.
The only difference is what happen in case of impact with a large immobile object (like an asteroid...)

Plus, as soon as you have 4 or more ships, you need to keep track of your moves in 3 dimensions.

[Lloyd Dupont]

23 minutes ago, Mugen said:

Plus, as soon as you have 4 or more ships, you need to keep track of your moves in 3 dimensions.

I was deep space chase, not around asteroid setttlement.

Hence it's just empty space.. 3D move is not that important that you must consider it.... There is absolutely nothing to take cover or hide out there, a straight line + some amount of dodging + some amount of hiding behind other space ship moving with you, is your only reasonable option.... no need for 3D map! ^^

Plus you can't really 3D map on a table...

[HierophantX]

So I liked this element of Joe Haldman's "Forever War" in that ship-to-ship combat in space was just done by computer because the math is just too hard. Meanwhile, I kinda think of the range problem with railguns to be more that after a certain distance your hit probability drops to nil because of the amount of time it takes to reach the target vs everyone's relative speed.

 

 

[Questbird]

6 hours ago, hix said:

alright let's make some wild assumptions:

Lasers do damage with heat, needing contact over duration to do significant burn. So you have to be close to keep contact.

Railguns do instant kinetic damage, but because of their relatively slow speed have less range.

Missiles/torpedoes do instant damage but have range limited by fuel. they can also be detected, so you can't shoot from too far away.

what else ya got?

 

Traveller had meson cannons where an antiparticle was calculated to decay inside the boundary of an enemy ship. Who knows what the range of that might be.

But OK. If it's close range the next thing is that people will most likely have the same weapons (lasers or some kind of radiation weapons are the most likely, given the speeds). Any weapon which hits is likely to be pretty deadly (unless you have force shields) so it comes down to who shoots first. So ambushes and stealth will play a big part. A ship without much signature (or deliberately powered down to have low emissions) would wait for another and then BLAM, light up, and light 'em up. Unless they get detected first, in which case the other ship alters course and speeds away.

[Warframe44]

On 12/4/2020 at 1:21 PM, hix said:

How to use the existing chase rules in the black void of space, some ramblings:

1. There's no top speed in space, so the speed stat is not needed. Accel is king, perhaps mitigated by the mass carried if you want to get that crunchy.

2. No friction and preservation of momentum means no turning rules are needed, but the "moves" table in the chase section would be altered.

3. The Handling stat should determine the "class" of ship, and keep them in line performance-wise.

4. The abstract ranges are perfect for space battles, as the distances are usually too weird to imagine.

What else ya got?

1. There is a very real speed limit in space. Light. Very fast, granted but that's it. No more. Complicating accelerating to light speed is that time slows the faster you go. When you reach c, time, for you, stops. Small point - i agree entirely with benchmarking acceleration, but depending on the ships relative velocities, the faster ship may simply not react quickly enough.

2. I'm not sure what you mean by this. Weapon facing will always be an issue, so vehicles still need to turn. Vehicles can't instantly change course.

4. weapons will only be effective if they hit. Any weapon, even light, takes time to travel to a target. It's conceivable that, in space, a laser could take seconds or even minutes to reach a target. If the target is stationary, great, but if it's not it's a whole different matter. This issue becomes more egregious when using lower (relatively) velocity weapons like rail guns, missiles, etc

So I think real numbers are still needed. At a different scale, granted, but weird to imagine? Is 1 million km harder to imagine in a space battle than 1000 km? I say use real distances but also factor in the time in takes for the weapon's payload to be delivered to the target

Nice post. Got me thinking about things I'll be using in my own game   😁

 

[hix]

22 minutes ago, Warframe44 said:

I'm not sure what you mean by this.

I was thinking of "facing" more than vector. A fighter, let's say, can reverse/adjust facing with very little thrust required and no resistance. Like in Babylon5/2000sBattlestar Galactica where they flip on a dime. As oppposed to naval combat where turning/facing is a big deal.

[Mugen]

9 hours ago, hix said:

I was thinking of "facing" more than vector. A fighter, let's say, can reverse/adjust facing with very little thrust required and no resistance. Like in Babylon5/2000sBattlestar Galactica where they flip on a dime. As oppposed to naval combat where turning/facing is a big deal.

Well, there will be no Air/Fluid resistance and no gravity, but Mass Inertia is still a thing in space, and depends on mass and geometry.

[Joerg]

On 12/16/2020 at 6:13 AM, hix said:

Lasers do damage with heat, needing contact over duration to do significant burn. So you have to be close to keep contact.

Pulsed lasers can have an energy output a lot higher than continuous lasers.

Continuous lasers will mostly heat the ablated matter as a hot plasma cloud, a cloud expanding away from the target.

The laser needs to interact with the target matter. If the target behaves like glass towards the laser used, comparatively little energy will be absorbed.

 

Rather than focussed lasers, you could simply slow-cook a target with by heating it constantly at a rather low rate. Heat disposal is a problem in vacuum. A space vessel in the rough focus of a lense may be in trouble.

Rather than aiming for hull damage, you can endeavor to fry sensors, weapon systems, drive systems, etc.

Electron beams or proton beams tend to be slower than coherent light, but will cause trouble even on misses as their magnetic fields interact with whatever you have going on.

Positron beams offer highly energetic matter-antimatter reactions when impacting on normal matter.

Any type of charged particle can be used in beams, and can be used to sandblast your target. Sandblasting sensors or mirrors protecting those sensors will blind your target.

 

Reaction drive blowout - whether photons, plasma or railgun slugs - can be an effective weapon. Decelerate into your target and wash it with particles, for effects listed above. If you can turn up the dirt in your exhaust, that can be a weapon. Doesn't have to be your own reaction drive - you could shoot a missile that just rendezvous-brakes into your target after outpacing it.

 

But then, any energy you expend will create an acceleration. The chasing vessel or missile will brake, the fleeing vessel will accelerate by firing.

 

On 12/16/2020 at 6:13 AM, hix said:

Railguns do instant kinetic damage, but because of their relatively slow speed have less range.

Railgun shells do instant kinetic damage upon impact, but hull armor may be layered with the equivalent of ballistic gel or foam. Range is unlimited, but targeting an evading target needs a lot of prediction, or a wide scatter of shots, and luck.

Personally, I would use foamed metal or foamed ceramics as outer hull plating, as it offers a lot if impact dispersal options, saves on mass, and also serves as ablative armore to beam weapons.

I would also want slugs that disintegrate into molecular dust after having traveled some time, especially if moving in high traffic areas. A cloud of separate atoms still has the same kinetic energy as the original slug, but dispersed over a wide cross-section the actual impact damage is lessened a lot.

 

On 12/16/2020 at 6:13 AM, hix said:

Missiles/torpedoes do instant damage but have range limited by fuel.

Guided missiles or autonomous drones may coast after having been released from a railgun, or a first stage drive, only to re-engage drive once they approach the target.

What damage these missiles do depends on the type of warhead you are using. Kinetic impact missile would do kinetic damage. The drive may double as source of a nuclear or matter-anti-matter explosion.

Nuclear explosions or matter-anti-matter reactions will create a point source of energy, and an EMP. Directed blasts makes them a short range beam weapon. Theoretically you could shoot a railgun or a bomb-pumped laser as a missile payload. Such payloads may even be strategically reusable. Against hostile salvage parties, they may aggressively self-destruct taking the salvaging drones or vessels along.

Flying into a cloud of anti-particles may ablate your hull and any external systems (communication, sensors, weapons, main and secondary drives) and may fuse what remains of your hull into a closed canister. Having the missile produce a beam of such anti-particles from a close distance will increase payload efficiency.

 

On 12/16/2020 at 6:13 AM, hix said:

they can also be detected, so you can't shoot from too far away.

Coasting missiles can be calculated, but slight lateral acceleration can take them out of their predicted trajectory.

The Honorverse grows nigh poetic about the means a wave of missiles can mess up your detection and countermeasures with a multitude of deceptions. That goes for missile guiding systems, too.

You could shoot swarms of remote-guided semi-dumb missiles and a slightly delayed autonomous guiding module, operating on telemetry from a spread of probes scattered around the target.

Last-stage sub-missiles may over-saturate anti-missile measures.

On 12/16/2020 at 6:13 AM, hix said:

what else ya got?

Depending on the softness of your science, messing with the curvature of space can be used both offensively and defensively.

Any form of FTL technology will add evasion and defense possibilities, new targeting options, etc. If FTL is unsafe if used in an environment with too much space curvature, how exactly is it unsafe, and can the catastrophic effects of a failed FTL transition be weaponized?

 

Electromagnetic pulse vs. hardening of your tech, especially your sensors and targeting systems.

 

The question is, what do you want from your space combat? Targets exploding upon receiving a hit, targets slowly beaten into submission, surgical strikes against critical target systems paralysing the target? Should space vessels have the equivalent of healing potions/spells in the shape of damage control teams, system redundance, etc?

Can you have emergency boosters, possibly sacrificing redundant ship systems for a performance boost? Do you wish to redline systems versus the maintenance rolls of ships' engineers?

Does your ship use life personnel or internal drones?

Do you have programmable structural material? If so, how secure is the programming? Can the ship produce replacements for destroyed parts, or does it carry spares?