Star Trek Starship Missile Weapons
Missile Weapons
Weight: 50 + (Spread divided by two, round down, times ten) for basic launchers; 100 + (Spread divided by two, round down, times ten) for advanced launchers
In addition to beam weapons, most ships carry at least one missile weapon - the torpedo launcher. Though many different types of torpedoes, such as photon, plasma, quantum, and gravimetric, are used, the launchers themselves are basically the same from one ship to another. They typically consist of tubes about 30 meters long made of tritanium, sarium farnide and similar materials. Sequential field induction coils and launch assist gas generators provide power to fire the torpedo.
One important difference between different torpedo launchers is the spread they can fire, meaning the number of torpedoes a launcher can fire in one round (either at a time, or more multifire bursts). Most launchers are limited to one to five torpedoes in a spread; advanced models can fire spreads of up to 10 or more torpedoes or more. (As of 2376, the maximum Spread is 12.)
The standard Starfleet torpedo launcher - type used to launch Type II photon torpedoes or Mark I quantum torpedoes - costs a base weight of 50 metric tons plus its Spread divided by 2 (round down) times 10. Thus, a launcher with a Spread of 10 costs 100 metric tons; one with a spread of 1 costs 50 metric tons; one with a Spread of 7 costs 80 metric tons.
For high-yield torpedoes, such as the Type VI photon torpedo, a special type of launcher is required (the normal launcher cannot fire them at the high-yield level). It costs a base of 100 metric tons, plus its Spread. Thus, a launcher to fire ten Type VI torpedoes costs 200 metric tons.
The standard Ranges for most torpedoes are Space: 1-150/500/1,750, Atmosphere 2-300/1,000/3,500 km. however, recent advances by Starfleet (and perhaps other powers) have increased the fuel tank size of the individual torpedo, extending the range of the missile to Space: 1-175/750/2,025, Atmosphere 2-350/1,500/4,050 km. (See individual ship descriptions for which type of torpedo is carried; switching from one to the other, or from one type of torpedo to another, does not change the weight cost of torpedoes or launchers). For every 1 Space beyond Long range increase the Difficulty to hit the target by +2.
To determine the accuracy of the torpedo launcher, By a Torpedo Targeting System. This is the same as an Auto-Phaser Interlock or a Disruptor Targeting System (depending upon what type of beam weapons the ship uses) in terms of weight cost and effect, and applies to a single torpedo launcher. Torpedo launchers must also buy a 541+ degree firing arc (50 metric tons), to reflect the self-guided nature of torpedoes.
Main Weapons: Phasers
| Auto-Phaser Interlock | Weight | Fire Control |
| Class Alpha | +0 metric tons | +3D+2 |
| Class Beta | +20 metric tons | +3D+1 |
| Class Gamma | +30 metric tons | +3D |
Main Weapons: Disruptors
| Disruptor Targeting System | Weight | Fire Control |
| Class Alpha | +0 metric tons | +3D+2 |
| Class Beta | +30 metric tons | +3D+1 |
| Class Gamma | +40 metric tons | +3D |
Torpedo Storage
Ships have to carry a sufficient load of torpedo casings and parts so that they have enough "ammunition" to meet any challenge they might face. Every 5 torpedoes occupy 5 metric tons of storage space. Probes, which are also launched from torpedo launchers, are usually stored with torpedoes; any one probe is equivalent to any one torpedo in terms of the area required to store it (thus, a batch of 15 torpedoes and five different probes takes 20 metric tons of storage space).
Microtorpedo Launcher
Weight Cost: 5 metric tons (+50 for Firing Arc); 100 microtorpedoes per 10 metric tons
A microtorpedo launcher is a device for firing microtorpedoes, small missiles loaded with chemical explosives. They have ranges of Space: 1/5/20; Atmosphere: 1-100/500/2,000, have a Firing Arc identical to that of a photon torpedo, and do 7D+2 damage (starfighter scale). The launcher costs 5 metric tons; 100 microtorpedoes occupy 10 metric tons. Regardless of how many torpedoes it fires, it has a Spread of 5.
Tricobalt Devices
Weight Costs: 20 metric tons per device
These powerful photon torpedo-like weapons are carried by a few Starfleet vessels. Not generally considered a weapon of war, the tricobalt device is used to destroy derelict space stations, crack open small asteroids so miners can get at their interiors, and so forth.
A tricobalt device can only be launched from a high-yield torpedo launcher. It has a range of 1-175/750/2,025. And uses the launcher's targeting systems to determine its accuracy.
Tricobalt devices must be prepared before firing. Preparing one takes one minute and an Easy (10) Capital Ship Gunnery Test; for every 4 points by which the Test Result exceeds 10, reduce preparation time by 10 seconds (to a minimum preparation time of 20 seconds). Failure indicates the officer must spend another minute and try again; Dramatic Failure causes the device to explode prior to launch and do its full damage to the ship. Tricobalt devices are not stored while prepared due to their volatile nature; typically a ship fires them as soon as they're prepared. For every minute (or fraction thereof) beyond one round which a ship keeps a prepared tricobalt device without firing it, the GM should roll 2D. On a roll of 2, the device explodes, doing its full damage to the ship.
A tricobalt device does 25D damage. Tricobalt devices cannot be multifired.
Chemical Rockets
Weight Costs: 50 metric tons for a launching tube; 10 rockets per 10 metric tons
Some less advanced races use rockets armed with chemical explosives, such as Merculite rockets fired by the Talarians. While this type of rocket can vary tremendously, most have a range of Space: 1/5/20; Atmosphere: 1-100/500/2,000m, a Fire Control of 3D+2, and do anywhere from 1D+2 - 3D+1 damage (capital scale) depending on its size. They can be multifired.