2) Power Plant. The main types are fuel cells, fission reactors, fusion reactors, and antimatter reactors. These power your ship and usually its drive.
- Certain drives require certain types of power plants. Certain power plants are only allowed if you equip certain types of drives.
- Power plants will automatically scale up in mass depending on your drive requirements.
- Power plant designs have a maximum output, meaning they can’t handle drives that above a certain power rating.
- Designs also have a specific power value, which is their mass per unit output.
- Finally, they have an efficiency rating, which determines how much waste heat you have to handle with your radiators.
- Power Plant development is mostly strict improvements, where most or all of those values improve one generation to the next. In looking over the power planet table, I can see exceptions (typically when specific power improves alongside a reduction in the max power), and I should probably reorganize those a bit so there are clearer lines of upgrades.
3) Drive. Drives have two key values: thrust and exhaust velocity.
- Thrust and mass together determine the ship’s acceleration, which is critical in both the strategy layer and the combat layer; for strategy, it determines how fast you can get somewhere (propellant permitting); in combat, it’s crucial to your ability to maneuver. Most drives can also increase their thrust for the duration of combat for improved maneuverability. Each drive can have one to six thrusters, so you can increase your thrust (and propellant consumption) during ship design.
- Exhaust velocity is akin to fuel efficiency in a car; it determines how quickly you use up your propellant when thrusting. Higher EV means you need to load less propellant and can have a lighter and thus more maneuverable ship overall.
- If the drive is powerful enough, no physical material can contain the drive plasma, and it requires a magnetic nozzle, which is composed of magnetic fields strong and stable enough to direct the plasma. This is an important tech you’ll have to develop before unlocking some of the game’s most powerful drives.
- If a drive pushes out sufficient mass per second, it uses something called “open-cycle cooling.” This means you’re able to pump most of your waste heat out of your nozzle instead of needing radiators for most of it. This can significantly reduce the mass requirements for your radiators. However, these drives tend to eat a lot of propellant.
- There is massive variation between drives in the design. It’s hard to predict how useful some of the weakest electric drives will be, but they’re there so you can experiment and see what design strategies you can make work.
4) Radiators. These expel waste heat from your ship, which is necessary for computers to work and your crew to not burn up. Radiators scale in mass based on your power plant’s size and efficiency. The game models traditional fin-type radiators, dust and droplet radiators, and filament/spike radiators. Advanced radiators expel more heat per unit of mass. Radiators can’t really be armored and still work, so they are especially vulnerable in combat – and some are more vulnerable than others. You can retract them for a time, though, if have you have heat sinks in utility slots.
5) Batteries. Batteries store power for your weapons and other systems. Your early ones are very slow to recharge from your power plant, potentially putting a limit on use of weapons that require an external power source.
6) Propellant. This comes in 100-ton tanks. You can add as many as you want. This is what you probably think of as “fuel” but that term isn’t quite right for a lot of drives -- in nuclear drives, for example, fuel goes in the reactor and is distinct from the propellant, which is the stuff that goes out your tail to push you in the direction that you want to go. Different drives have different types of propellant; when you refill your tanks, you’ll draw down your space resources based on the composition of that propellant.
7) Armor. You may select armor materials and thickness for three parts of your ship, the nose, tail and central hull. You’ll actually track four armor values in combat, with the hull divided into two separate lateral facings covering 180 degrees each, which have equal thickness. Technological improvements lead to better materials that absorb more energy per unit of mass. As our ships are fundamentally cylinders, armoring their long sides is relatively mass-expensive – which begins to point to certain tactics in combat.
8) Nose hard points: Nose weapons fire in a limited arc – with some (like spinal railguns) more limited than others. Weapons are rated by how many hard points they take up, so you can conceivably equip four little cannons or one big one on lancers and titans. Nose weapons are generally more powerful than similarly sized hull weapons.
9) Hull hard points: Hull weapons fire in all directions around the ship. Each hard point consists of two mounts on opposite sides of the hull so there’s always a full field of fire. These always work in tandem and share ammo, and only one will fire at a target – it would be too fiddly to ask you to try to maneuver to bring both to bear.
10) Utility Modules: This covers everything else a ship might do. These include heat sinks, additional batteries, space marines, a science lab, systems that improve drive or weapon performance, space station and outpost kits, and ISRU modules.
Another critical value that comes out of the ship design as a whole is its angular acceleration -- how quickly it can rotate its facing. The game internally calculates moment of inertia, which is a product of mass and length, and this leads to smaller ships being more nimble than larger ones. With flanking likely to be an important part of combat, we expect this will keep smaller ships viable as the campaign goes on.
All modules either have a fixed resource cost, or a scaling one if the module itself scales (like with power plants and radiators). These are measured in space resources (water, volatiles, etc.); if you have a shortage, you can instead spend boost and money to ship some from Earth.
Art notes: Each ship model will have at least two versions (thanks to Kickstarter supporters backing a second ship set!) you can choose from. The attached drive, radiator and weapon models will vary depending on your loadout. The ships will also have different coloring based on which faction is fielding them.
I also want to acknowledge a current bit of unrealism in service of coherent art and design flexibility: In three places, we didn’t fully translate the numbers into the visualization. These are propellant volume, power plant volume, and radiator surface area. We don’t really limit how big a power plant or how many propellant tanks you can use in a particular hull. You will show more radiators if you have more, but it doesn’t scale up beyond a certain amount. If I did want to enforce these, I’d probably institute a mass cap on each -- limiting how many tanks you could carry, how big a power plant you could field in a given hull, and how big the radiators could be. I’d fear that would constrain design options too much, especially with smaller ships, but I’ve half-changed my mind in composing this DD, and might do something like opening some distinct miniaturization techs to address this. But we’ll see what feedback we get during testing and whether some limits are in order.
One other thing we’ve been considering is how to handle displaying all the crunchy numbers that underlie the space travel and combat model. Right now, our UIs give you the full report; e.g. this drive has this many million Newtons of thrust, etc. While useful for debugging, that may be … a lot for players to take in and make informed decisions. So one thing on the to-do list is a comparison chart between systems you’ve developed; another is to develop a graphical representation of those big numbers (which really need to handle logarithmic scaling) for easy reading.
We’ll detail in future diaries about space navigation and combat, but also know that we’ve focused on making sure your decision sets are clear and digestible when working with your ships and fleets, in and out of combat. A lot of detail here is what’s going on under the hood; the decisions in both the strategy and combat layer are built around where you want to be by a certain time, and whether you want to pay the Delta-V to make that happen.
Roles
Another part of ship design is setting a role for the class. Roles tell the game whether the ship is a combatant or noncombatant, what range it should engage in during combat, and what its strategic range is (so how much Delta-V it can carry). The “Standoff” role, for example, indicates a ship design with medium strategic range and a long combat engagement range, while the noncombatant “Outer System Colony Ship” role means the ship is carrying hab kits with nuclear reactors instead of solar power.
The role affects a few things: one, it tells the autodesigner what systems to favor in building the ship if you don’t want to design module-by-module; two, it helps locate your ship in its fleet formation. More detail on formations in a future dev diary, but a ship designated as a noncombatant, for example, will be placed at the back -- or, more accurately, the bottom -- of a formation, even if it is well-armed. It’s also an important setting for the AI and was initially designed for the alone, until we figured out it could help the player, too. Finally, it’s a useful marker for keeping track of all your various ship designs.
You do have some constraints on what roles you set for your designs – can’t designate a colony ship without the right module, for example – but you also have some freedom. If you want to build a short-strategic range, short-combat range ship (normally an interceptor) and call it an attack bomber (which is meant to be long/long) so it will place itself differently in formations, and fight differently if you turn on AI control of the individual ship, you can do so.
Weapons
Weapons come in six types, and up to four sizes per mount type (nose/hull).
Some weapons can only be used against enemy ships and habs; others can only be used against missiles and projectiles, and some may target both.
Weapons also have an effective range value that represents the precision of their targeting systems.
The types are:
- Guns: Good old-fashioned cannon (chemical slugthrowers) with performance characteristics similar to modern naval weaponry. Low-tech, cheap, and don't drain your battery.
- Missiles and Torpedoes: Will chase the target. Constrained by ammo limitations. Nuclear weapons are among the warhead types. The difference between missile and torpedo in this context is mass; missiles go fast faster and have larger magazines while torpedoes carry heavier warheads. Also doesn't drain your battery.
- Magnetic weapons: Covers railguns and coilguns that launch high-speed projectiles that can be dodged or shot down. Can be used in orbital bombardment.
- Lasers: Never miss. Damage falls off over distance. Higher input power, larger optics and higher frequencies lead to more damage. Can be used in orbital bombardment, with some limitations for high-frequency weapons trying to bombard through an atmosphere.
- Particle weapons: Short-range weapons that can do severe damage to a ship’s internal components if it penetrates a ship’s armor. Also effective point defense weapons.
- Plasma cannon: These are essentially high-speed, low-mass projectile weapons; their design is based on what descriptions are available of the real-world Shiva Star and Marauder projects. In practice, we’re modeling them as long-range, low rate-of-fire weapons to give them a distinct role in combat. Deep in the tech tree.
And that’s it! Next up will be fleet movement in the strategy layer.