2025-11-30 Stealth ships in Kinetic Energy
Regarding Kinetic Energy and space combat, I had decided early on that I didn’t want the lasers and sandcasters from Classic Traveller nor the missiles from Macross. The lasers seemed not to work all the well in or reality, sand seemed way to heavy, and missiles … I just kept wondering how they would work.
It didn’t take long, though, and @eldadoinquieto@mastorol.es asked me about missiles and self-propelled projectiles. That made me think about the situation some more.
The first argument against missiles I has was about payload and delivery. Missiles can’t correct their path all that much unless they are slow. And if they are fast, then something that’s even faster and works with kinetic energy is going to be better than something that needs thrusters for course correction and explosives.
The second argument I had was about the kind of game I wanted run. It’s not obvious to me that having torpedos makes the game more interesting. Unless there’s a need for a kind of U-Boot mini-game. But that’s not how I see ship combat going.
@mdhughes@appdot.net argued that the railgun could shoot torpedoes and then the torpedo can course-correct. After all, the space ship drives are already breaking the laws of physics. It really all comes down to the size of these implausible engines.
Current rail-guns get muzzle velocities of 12Mm/s (12,000 km/s). Does the torpedo need to hit the target? A question @yora@mastodon.gamedev.place raised was this: If it needs to detonate something, how likely is it to detonate “near enough” to the target if it is travelling at these speeds?
These high velocities are also what makes me think that a tiny thruster onboard the projectile cannot course-correct significantly compared to that muzzle velocity.
Without a gas, there is no “explosions” in space (no pressure wave to damage a nearby target) so a warhead would have to deliver shrapnel, like a grenade, or deadly radiation (that decays rapidly as the distance increases). @nyrath@spacey.space has an article on the Project Rho site, Nukes In Space.
And now I wonder whether I’d like a game where radiation poisoning is common. Perhaps it’s easier to postulate that spacesuits safeguard humans from radiation, rendering nuclear weapons in space ineffective or at least inefficient compared to rail-guns.
Is shrapnel the way to go? Sacrifice some mass, reducing kinetic energy, add a little warhead that just fragments the mass, producing shrapnel? If a single fragment was still deadly, then the rail-gun could also scale down or shoot every piece individually. Without drag, there is little point in shooting a grenade, I think. Turn the rail-gun into a rail-shotgun. Or increase the frequency and improve the aim. All these scenarios seem to be things I don’t want to model because they don’t lead to interesting decisions at the table. An abstract “rail-guns are the only weapon that can harm spaceships” is good enough.
So perhaps now it’s time to consider the alternative: Stealth ships trying to sneak up to slow-moving or stationary targets in order to deliver “bombs” or torpedoes. Would such a stealth ship run into mines, as suggested by @eldadoinquieto@mastorol.es?
I am sceptical. If the approach to a hideout is “mined” – what happens in the game? Mines seem like something one would have to introduce because it allows some specific game experience. Perhaps the only thing we really need is for large stationary objects like stations to have the means to disable ships near the docking bays. Then call it autonomous mines with thrusters or something like that. Or torpedoes launched by a stealth ship.
@isaackuo@spacey.space suggested stealth ships and torpedoes running with liquid hydrogen cooling and noted that YouTube is full of videos about sub warfare.
How would this end up playing out in Kinetic Energy? Jump into a system, accelerate towards the target, switch on cooling. This gives you the chance at one bombing run. The enemy knows you have arrived but doesn’t know when exactly you’ll fire the torpedoes since the exact vector remains unknown. Alternatively, your ship is lying in ambush near a station. You know the mark needs to pass through here. When it arrives, switch on cooling. They don’t know what’s coming.
Cooling limits the number of stealth rounds. For gaming purposes, let’s say you get three rounds. Roll Education + Pilot once per stealth round to continue the approach and get the Gunner a cumulative +1 bonus. If you fail, you are discovered.
If you are discovered early, the target can deploy countermeasures to foil the torpedoes. Use Education + Pilot to escape if mobile, use Intelligence + Gunnery if immobile and armed with smaller guns to shoot down torpedoes.
Of course, if you are discovered early, the target can also use their firepower to target the stealth ship as it tries to get away.
As for the trade-off: four torpedoes per turret, one cooling turret per stealth round (up to three).
A medium attack boat would have a Martial Mass of 8: 1 + three cooling turrets (max) + three torpedo turrets (12 torpedoes) + 1 rail-gun. Rolling 8d6 for both Integrity and Stability I get 28/29. The pilot has Education-8 and Pilot-2; the three torpedo gunners have Intelligence-8 and Gunnery-2. Checking for stealth approach: 10 … 7 … 6. Success. The Gunnery bonus is +3 therefore the torpedoes cannot miss unless there is an additional defence, therefore the gunners don’t need to roll. All 12 torpedoes hit the target, dealing 12d6 damage to Integrity and Stability on the first round. The attack boat is out of torpedoes but there’s still the rail-gun. That one doesn’t get a bonus due to the proximity so a regular 1d6 ≤ 8 + 2 is required. Rolled a 7 and scored another hit for 1d6 damage.
I’m still not sure whether I like this. A Tactics skill check to fire back at the stealth ship and torpedoes in the last round? Or just accept this? Or allow the firing of just one torpedo per turret and round, so this attack boat can fire just three torpedoes the first round? Or is it fair that the stealth ship can take down a bigger ship. And what about the next encounter? The attack ship is a sitting duck: It has just a single rail-gun and it takes 8 rounds to get to escape velocity.