Privatization of Defense

With humanity spread far and wide across dozens of colonies and hundreds of lightyears, a centralized defense force unified under a single command structure is impractical. As a result, numerous individual planetary defense forces have been established since the dawn of the interstellar age, and many of them have been merged into larger sector-wide defense networks.

However, for isolated colonies on the frontier (or those who simply don't have the funds to purchase military hardware), private military companies become the preferred solution when trouble starts brewing. A number of space-faring PMCs (of varying degrees of legitimacy) have been founded to cater to these colonies, with the big three being Allegiant Combat Enterprises, Stratagem Contract Armament Resources, and Apex Risk Management Services.

Military-Industrial Complex

The majority of all modern spacecraft are designed and manufactured by one of two dominant entities – STARCON, and Xenodyne Kosmos.

STARCON (Space Technologies Applied Research Consortium) is a joint venture between three prominent aerospace manufacturers on their respective worlds – General Galactic, Stellaris Aerospace, and Horizon Flight Dynamics – formed to produce mainly combat aerospace craft for the various militaries of the colonial systems. In the course of bidding for lucrative government contracts, the three companies realized that instead of submitting three decent entries individually (which would cost more and dilute the pool of proposals in the process), by combining their resources to build one outstanding entry, it increased their chances of winning the contract and generating profit for all of them. The strategy worked, and to date, STARCON has grown into an industrial juggernaut that almost single-handedly holds every major aerospace defense contract.

Xenodyne Kosmos is the second-string competitor to STARCON, providing lower-quality (but perhaps more importantly, lower-cost) alternatives for interstellar combat aviation. Their products are popular with rogue states, criminals, independent operators, local planetary defense forces, and anyone else who needs an armed spacecraft on a budget. As a way of setting themselves apart from their competitors and to increase appeal among their target demographic, Xenodyne designs tend to feature more aggressive styling with cosmetic features such as sharp edges, bladed wings, and darker colors.

Interstellar Travel

Due to the fundamental laws of physics, faster-than-light travel is impossible. However, there is a method that allows for apparent faster-than-light travel. Known as the Spacetime Geodesic Fold generator, it's not called a drive because it isn't a method of propulsion, but rather a device that plucks a ship from its current location and near-instantaneously deposits it at its destination by creating an artificial micro-wormhole through which the ship can travel.

There are limitations to the system, in that a ship cannot make the fold from anywhere it wants. It has to be outside the influence of any major gravity wells and so a ship must have conventional means of propulsion (typically a fusion drive) in order to reach fold distance, as well as to travel while within a star system.

Theoretically, there is no limit as to the distance the SGF generator can move a ship, but in practice, the limiting factor is the ship’s navigation computer and its ability to safely calculate and plot a fold line within a finite distance of the ship. To attempt a ‘blind’ fold beyond the range of the navigation computer means the vessel could end up colliding with a star, planet, black hole, or other unknown hazard. Ships outfitted with more advanced navigation computers have an advantage in that they can travel further, and with fewer folds, than less-advanced ships.

Tactical Systems

While energy weapons do exist at the current tech level of the Colonial Systems, they are not man-portable and are seen as somewhat rare and exotic (expensive, too!). Ballistic weapons are still by far the most common, with both chemically- and magnetically-propelled options seeing regular use. Guided missiles are also very common, being the premier choice for space combat over inert projectiles (“Sir Isaac Newton is the deadliest S.O.B. in space!” etc.).

Defensive Systems

At the current tech level of the Colonial Systems, energy shields are not a thing. Or if they are, only exist as impractical early-stage prototypes that consume inordinate amounts of power and only work under controlled laboratory conditions. Ships are primarily protected by ablative armor panels that fragment to absorb and reduce the impact energy transfer of ballistic projectiles. When hit by energy weapons, they will vaporize to dissipate the heat away from the ship, and the vaporized cloud of particles helps to further block the beam and mitigate the damage.

Extraterrestrial Life

At this moment in galactic history, no sentient extraterrestrial life has yet been encountered by spacefaring humans, nor has there been any hard evidence discovered to suggest that it might exist elsewhere. For the time being, all indications point to humans being alone in the universe.