UPT: Spacecraft Weaponry

A brief overview of classes of weaponry employed by UPT spacecraft and the general characteristics of them. This page does not discuss specific weapon models. Besides the military, law enforcement and civilian spacecraft may still be armed.

The three main users have different requirements which influences their weapon choice. Military spacecraft aim to destroy the enemy, law enforcement spacecraft aim to disable and apprehend, while civilian spacecraft have armament if any for their own protection.

The characteristics are primarily taken from the videogame Children of a Dead Earth.

Gauss Cannons or electromagnetic accelerators use electromagnetic forces to propel projectiles at high speed, tens or even hundreds of kilometres per second. The term "Gauss cannon" has become generalised and covers coilgun, railgun, and more designs.

+ Dense projectiles excellent at penetrating armour and solid structures.
- Not as long range as large-aperture lasers.
- Not as precise as lasers.
- Big power requirements.

Gauss cannons are the main weapons on most military spacecraft (excepting those focussed on missiles or fighters) including strike fighters. They are rarely seen on civilian or police use; civilian spacecraft usually don't have enough reactor power and the police prefer lasers.

Self-contained Gauss cannons are constructed as a single unit with an integral power supply and evaporative cooling system, in contrast to standard Gauss cannons that use the spacecraft's central power supply.

+ Offer performance close to standard Gauss cannons.
+ No load on the spacecraft power or cooling system.
- Close, but not quite as good.
- More expensive.
- No standardisation of power and cooling cartridge designs, which can result in difficulty resupplying.

SCGCs are popular retrofits to civilian spacecraft that operate in piracy-prone areas - and that includes the spacecraft of the pirates themselves! They have largely replaced chemical guns in this role.

Chemical guns, despite firing projectiles at a much slower speed than Gauss cannons, can still have strong penetrating power but with a very short effective range.

+ Cheap to buy and maintain.
+ Little power required.
+ High-stability propellants can be used to largely eliminate the risk of ammunition explosion.
- Very short effective range.
- Risk of explosion if inferior propellants are used.

Some military craft carry them to provide extra close-up firepower, but chemical guns are more commonly seen on civilian spacecraft. In any event they tend to be present on older models and are often replaced with SCGCs at a refit. That said, chemical guns do have the advantage that suitable ammunition is often easier to obtain.

Small-aperture lasers are somewhat vaguely defined; in general any laser with an effective range similar to or less than a Gauss cannon is considered small-aperture. The UPT primarily uses photonic arrays rather than traditional lasers, which thus do not have an aperture in the usual sense, but the distinction persists. These photonic arrays are what give many UPT spacecraft a distinctive iridescent appearance.

+ Excellent against 'systems' on a target - engines, weapons, etc - thanks to the precision of a light-speed weapon.
+ Virtually instant targeting with photonic arrays, no need to physically move optics to aim.
- Mediocre at penetrating armour. It can take many seconds of sustained laser fire to produce the penetrating a single kinetic impact could.
- Inefficient, both in terms of converting input power to laser energy and in converting laser energy to destruction of the target.
- Big power requirements.
- Big cooling requirements thanks to inefficiency.

Small-aperture lasers are universal as point-defence weapons to take out hostile missiles, fighters, drones and similar and are seen on both military and civilian craft. They are the primary weaponry of (non-strike) fighters and on police craft.

Large-aperture lasers are distinguished from small-aperture ones by their much greater effective range. They also invariably have much greater power. Most in UPT service are traditional designs but some use photonic arrays.

+ Massively powerful, capable of brute-forcing their way through armour quickly.
- Big, and thus big targets themselves.
- Monstrous power and cooling requirements.
- Phenomenally expensive.
- Slow aiming on traditional designs.

Large-aperture lasers are standard on military space stations, and bases on vacuum worlds. They dominate the space around them; any would-be attacker must find a way to deal with the laser or otherwise suffer massive losses.

Particle beams are not used in space. Charged particle beams spread out way too much in vacuum, unlike in atmosphere where self-focussing effects keep the beam together. Neutral particle beams are usable in space but the UPT Space Force feels they offer limited advantages compared to lasers or X-ray charges, not enough to offset the considerably greater engineering difficulty.

'Missile' and 'bomb' weapons to come.