Planetary Defence Force

A Planetary Defence Force (usually abbreviated to PDF) is the **primary military force of an individual Imperial world**. The PDF is under the control of the world's governing House rather than direct Imperial control, including the raising, training, arming, leadership, etc., of such units. According to Imperial law, all Imperial planets must maintain a standing army in order to maintain the planetary government's (and thus the Imperium's) control over the world against any possible invasion or insurrection, as well as maintianing law and order.

The PDF, as essentially the local military of an Imperial world, has had some, but overall little standardisation in the past and can take many forms. The equipment and doctrine of a PDF can differ widely depending on the House which rules a world, for example regarding their own pride into their military, their economy and how much they are willing to spend of it on their PDF. A House may train their soldiers extensively, make sure they are fed well and sleep in good housing, and equip their PDF's Soldiers with high quality equipment like armor, environmentally sealed and resilient clothing and masks, as well as high powered weapons, while another may be equipped with mainly weapons and clothing, for example due to a world's current low economic wealth.

When facing any internal or external threat, it is the responsibility of the PDF to engage the enemy until Imperial reinforcements like Transports with Legionaries and Raiders or a AstroNavy Quick Reaction Force can be mustered by the nearby Fleet Command.

On average each system has 250 Million (0.5% of a average system's population) PDF Soldiers divided into Infantry, Artillery, Medical, Orbital Defense, Interplanetary-range weapon stations and light, versatile warships who serve as orbital guard and controllers to e.g. search incoming or outgoing vessels and combat smaller pirate, criminal, rebel and terrorist activities. This amount of soldiers may be spread differently depending on the system itself, for example they could be on various planets, moons and space stations throughout the system, or only deployed on one world. The smallest PDF a civilized world, meaning a world which is not in the colonial state anymore, has is roughly 20 million in general, with the highest being in the Billions, such as the Sol System which has 1 Billion Legionaries alone permanently dedicated to it, and 100 Billion of PDF forces.

**Weapons**

The Soldiers of a PDF most commonly use Laser Rifles which are directed energy weapons that produce beams of high-intensity amplified light to produce heat damage on a target. Laser Weapons are very easy to produce and maintain, highly reliable and a trusted and proven design which has been used and overhauled by humanity for ten thousand years.

No solid ammunition is used for the Laser Rifles -- only power cells which can be recharged and quickly swapped when depleted with another fully-charged power cell. This makes them ideal for large troop formations like the Imperial Planetary Defense Forces.

While the accuracy of the laser beam cannot be distorted by wind like ballistic ammunition, it can be quickly diffused by heavy particles in the air such as smoke and hence lose its power over long distances.