Photon Torpedo

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Technology Data
Name Photon Torpedo
Type Torpedo
Introduced 2267
Affiliation Federation
TechStatus Star Trek Canon
Contributor Czarr Rom

The Photon Torpedo is a power, long range, projectile weapon commonly employed by Federation starships and space stations that has been in use for well over one hundred and fifty years. Variants of the technology have also been developed and adapted by a number of other powers in the region around the Federation.

Today, within the Federation and Starfleet use of the photon torpedo has largely been superseded by the more powerful and safer to use Quantum Torpedo. Many older vessels and those of other powers still carry photon torpedoes though.

Technical Specifications

The modern photon torpedo is largely the same device as was originally developed over one hundred and fifty years ago. Advances have been made in that time in the sophistication of the technology and the power of the warhead but in basic terms the operation of the device is the same.

Inside a Photon Torpedo

A photon torpedo comprises of an elongated elliptical body around 2.1m long, 0.76m across and 0.45m high. The mass of the casing is around 247.5 kilos when not loaded. The warhead of the photon torpedo comprises a maximum of 1.5 kilos of antimatter and 1.5 kilos of matter. These are divided into many thousands of small pellets suspended in a magnetic field - smaller yields can be achieved by reducing the number of such pellets in the torpedo. Also included in the torpedo are target acquisition, guidance and detonation assemblies and a warp sustainer unit (which is charged by the launching vessels own drive field at launch, boosting the torpedo speed up to Vmax = Vl + (0.75 Vl / c), where Vl is the velocity of the launching vessel).

Velocity of travel

If launched at low impulse velocities the torpedo will accelerate to a 75% higher sublight speed; launch at high impulse speed will not push the torpedo into warp so a torpedo launched at impulse speeds does have an upper velocity limit. If launched during warp flight the torpedo will continue at warp until the sustainer is exhausted. Torpedo range can be extended by utilizing the matter / antimatter warhead to power the sustainer, although this causes a corresponding loss of warhead yield.1 For a mid-range yield the torpedo can achieve ranges of some 3,500,000 kilometres at sublight speeds.

Use as probe casings

Photon Torpedo Layout

The photon torpedo carries a guidence system and can home in on a target. The warhead of a photon torpedo can be removed and replaced by sensor packages or other equipment. Some advanced models are fitted with full warp drives for use as long range high speed probes - the Class VIII probe can cover up to 120 light years, or reach Warp 9.5, while the Class IX probe can cover 760 light years or reach the same speed. On one occasion such a device was used to transport a Federation diplomat to an urgent rendezvous.

Torpedo Launch Systems

There are currently eight major photon torpedo launch systems in use within the Federation :

2nd Class Photon Torpedo Tube

Dating from the late 23rd century, this model is now only in service on the Excelsior, Miranda, Centaur, Oberth, and Constellation classes. This tube is capable of firing one photon torpedo approximately every four seconds.

Standard Photon Torpedo Tube

A modern version of the 2nd class torpedo tube, this model can fire a torpedo every two seconds. It is more compact than the older model, has lower maintenance requirements, and is less prone to overheating with prolonged use.

Burst Fire (Type 1) Launcher

Photon Torpedo Launch

One of the most important advances in torpedo tube technology, the burst fire tube allows more than one torpedo to be launched simultaneously. The Type 1 model can load and fire a cluster of four photons every 2.85 seconds; although this makes the tube almost three times as bulky as a standard tube, it allows many targets to be engaged simultaneously. The Type 1 is fitted to the Ambassador class as well as various starbases and space stations.

Burst Fire (Type 2) Launcher

Designed for larger vessels, the type 2 burst fire torpedo tube can fire up to eight photons every five seconds, giving a greater overall rate of fire and increasing the number of targets which can be engaged simultaneously.

Burst Fire (Type 3) Launcher

Developed to arm the Galaxy and Nebula classes, this tube can fire up to ten torpedoes every five seconds - a 25% increase over the type 3 - or alternately can fire single rounds at a high rate of fire.

Burst Fire (Type 4) Launcher

The type 4 is the most powerful photon torpedo tube currently in service within the Federation. It can fire a burst of twelve torpedoes every five seconds, and currently is only fitted to the Sovereign class starship.

Pulse Fire Launcher

Developed for the Akira class, the pulse fire tube is a modification of the burst fire tube. The loading and pre-fire stages can hold up to four photons simultaneously, but the launch tube itself is only of sufficient size to fire one weapon at a time. The pulse fire tube therefore fires four rounds in one second, then pauses for three seconds to reload with the next four photons. Overall rate of fire is therefore one torpedo per second.

Micro Tube

This system was developed to arm small vessels such as runabouts (such at the Danube class) and shuttlecraft. It fires a compact torpedo with a much smaller warhead than the standard models.

Yield Calculation

Through basic calculations we can derive the maximum energy produced by a detonation of a modern photon torpedo. The basic power of the annihilation of 1.5 kg of deuterium by 1.5 kg of anti-deuterium is approximately 64.53 megatons (E=mc²). Unfortunately, currently Starfleet does not have the ability to focus the blast photon torpedoes at a single target. Therefore, in an optimum situation we can expect the shields of the target vessel to receive about 30% of the energy, with the rest of it dispersing uselessly.

To delve deeper into the subject, consider the fact that the resulting energy is emitted in various ways (such as gamma rays and exotic particles). At the same time we know that photon torpedo casings are extremely tough and dense - as mentioned above, one survived a fall from orbit into an atmosphere of a planet, completely intact. This density allows us to estimate that the photon torpedo casing can absorb a significant amount of the energy emitted by the deuterium-antideuterium annihilation.

For an approximation, lets assume that only 90% of the energy is absorbed by the casing. Just as during a nuclear detonation process, the result of this absorption will create a plasma fireball traveling at an enormous velocity composed out of the superheated torpedo casing. If we assume the same time scale as for a standard nuclear weapon, the plasma ball will expand at 30 km/s, impacting the target of the photon torpedo.

To sum up, these calculations tell us that a photon torpedo detonation will deliver approximately 17 megatons of energy (64.53 * 0.3 * 0.9) to the target vessel in the form of a physical impact and various types of radiation.

OOC Information

The photon torpedo is now only standard armament on older vessels although the technology remains aboard by way of probes which use the same casings as the photon.

See also