Torpedo

The USS Excelsior firing photon torpedoes

A Romulan Bird-of-Prey firing a plasma torpedo

The USS Defiant firing quantum torpedoes

A torpedo is a self-propelled, self-guided weapon. Torpedoes of some type are part of the standard weaponry of most Starfleet vessels in the 22nd to 24th centuries.

Torpedoes are primarily used in space combat as an alternative to directed energy weapons such as disruptors and phasers. Torpedoes can be configured before launch to fit various specifications. Normally a torpedo is equipped with a warhead, and the explosive yield of this warhead may vary depending on the type of torpedo. Torpedo launchers bring the weapon into the launch tube and allow fire control from the ship's bridge, although a torpedo can be launched manually. (TNG: "Masks") Most of the time a tactical officer is responsible for target acquisition and launch sequence.

The maximum effective range of a torpedo depends on its type. Range is dependent on propulsion and acquisition capabilities. Propulsion is categorized basically by whether the torpedo is warp-capable or uses another method of propulsion. Some types of torpedoes are equipped with a self-destruction mechanism. For those types, if a torpedo needs to be aborted and destroyed, due to for example a targeting acquisition problem, it can be destroyed.

The torpedo guides itself via internal sensors that can be configured by the tactical officer. (TNG: "Genesis") The advantage is that a firing pattern can be established whereby multiple torpedo launches can be coordinated to hit a single target and thus make the best use of every torpedo's explosive yield. (TNG: "Pen Pals") When necessary, the device's internal sensors can be replaced by specialized sensor packs, allowing for additional flexibility in use; for example, using a sensor pack designed to detect gaseous anomalies could enable a torpedo to lock onto impulse engine emissions. After configuration, the torpedo can be fired and will automatically acquire its target. (Star Trek VI: The Undiscovered Country) Some torpedoes feature advanced artificial intelligence to make the decisions about target acquisition, defensive maneuvers, etc. (VOY: "Warhead")

Torpedoes are used by different species and vary in type, appearance, explosive yield, and effective range. There are several types of torpedoes:

• Spatial torpedo - Triton-class spatial torpedoes were used by Starfleet in the 22nd century
• Antimatter torpedo - an antimatter weapon, used by Kelemane's species
• Photonic torpedo - an antimatter weapon, used by Starfleet and the Vissians
• Photon torpedo - the most common type of torpedo, used by multiple species
• Quantum torpedo - an advanced weapon, used by Starfleet, the Terran Rebellion and the Cardassian Union
• Plasma torpedo - used by Romulan, Cardassian and Kazon forces
• Gravimetric torpedo - a heavy weapon with a gravimetric charge, used by Starfleet
• Series 5 torpedo - an antimatter torpedo with artificial intelligence developed by the Druoda
• Transphasic torpedo - an anti-Borg weapon, originally developed by Starfleet in an alternate timeline
• Chroniton torpedo - a torpedo in temporal flux, used by the Krenim Imperium
• Stratospheric torpedo - a torpedo used in planetary atmospheres, used by Starfleet and the Maquis
• Pulse wave torpedo - a torpedo used to disrupt anomalies

Background

According to Star Trek: Deep Space Nine Technical Manual (page 92), torpedoes, like auxiliary craft, are equipped with shield window transponders. This allows them to be launched while the shields are active, as they pass through during a window in the shields. Canonically the concept of shield windows was introduced in the Star Trek: The Next Generation episode "The Wounded", where such things as beaming are possible for 1/50th of a second between sensor systems cycles.