So the Terran Coalition Navy is top dog but there's some other folks. The terran Coalition Marines are the next largest service and lets not kid ourselves. They're marines. Their job is to get on the ground and handle violent situations. Most TC Navy ships have Marines attached for planet missions. These guys and girls are rough and tough and very focused on the mission. I hesitate to say that they don't think about the hows and whys of their missions - they aren't dumb grunts and the level of tech they need to master isn't small, but career marines.... like to fight and generally don't much care who it is as long as they are backing their buddies up. They go to where the Navy takes them, they get their orders, they complete their orders. Then they party. And they party hard. Marines tend to be fairly loyal to the Coalition since they are usually from settler or core worlds.

The Colonial Forces is actually a catch all term for a very basic concept. This is a world's standing force. If you live on Alpha Centauri for example, you don't necessarily want the TC Navy and Marines called in for small stuff. So you have planetary military forces. In well established worlds, this will include ships and navy vessels and patrols of their own territory. There will be an army on planet. On smaller colonies and outports, things are less organized and there may be competing "armies". On worlds without a strong sense of civiliazation, there may be battling strong men and gangs. However colonial forces are not necessarily weak or poorly trained. Especially on core and wealthy settler worlds, the colonial planet forces can be VERY well equipped, and their weapons may include powered suits that the Coalition no longer uses. (In fact some planet forces may have stockpiles of powered combat suits since the tech is very good, perhaps too good for mere colonials to have in force as far as the TC is concerned)

And then we have the Terran Coalition Explorer Corps. This is the smallest official branch of the Terran Coalition military. While they do recruit, they typically get a lot of their personnel from the already established forces as transfers. If you are TC military and you get zoned, you are almost immediately transfered to the XCorps. These folks are basically military scientists. They have the military training, but they are basically poking around space and the outports looking for exciting new stuff to play with. They get called in first when an outport or a settler world "goes dark" and they have a reputation for being cheerfully disrespectul and irreverent. They respresent the Coalition, but because they function on the outskirts, there tends to be a lot of noses thumbed at rules. They also are much more democratic in some respects. Rank is rank, of course, but no one cares if you're a settler or a zonie, if you're doing the job, you're the one who gets the reward. I tend to see them in general as science orientated Special Ops people.

Basically the top dog is the Terran Coalition Space Navy. They have the big ships and the personnel. They not only spend their time enforcing the coalitions orders, they patrol, they assist in rescues, they defend against incursions by Velelvians and other aliens. They're not bad people, in fact they are very typical military people in that they are there for the people and the Coalition. However, the TCSN is huge! And that means there's a lot of internal stagnation. It's relatively easy for a less than exemplary officer to have a nice career without actually doing anything other than ride in ships from place to place. The navy tends to rely on bombing from above as a tactic, using their ships as carriers for fighters, and dropping off marines and recon units.

Being a pilot in the Navy is fairly prestigious but also filled with pitfalls. Core worlders get preference over settlers for training and advancement (and this is true in other specialties in general) and pilots tend to advance quickly, up to a point. The higher the rank, the more settlers who get shaken out of the mix, despite skill. Resentment in pilot quarters is building but there's not much to be done. A pilot who leaves the navy on honorable terms can easily find lucrative civilian work on any worlds, so pilots tend to be daredevils in the air, but conservative in their choices otherwise,in order to protect that pay off. Of all of the settler people who enter the military, a pilot is the profession most likely to "promote" to living on a core world. That's status. That also breeds resentment.

Depending on the ship, there can be a lot of engineering staff and bridge staff and in the Navy, these tend to be bright, well trained people but not necessarily creative thinkers. Plodders. Military types, in other words. The Navy has an Academy for its career officers, and the core and more advanced settler worlds have their own officer programs but the fast track to the Admiralty? Is the Terran Coalition Naval Academy on Luna. Academy grads get the good assignments and the creative jobs in intelligence, recon, etc. There is some resentment to this system, but basically the settler worlds are kept appeased by having the occasional "hero officer" fast-tracked. Those officers are watched very carefully. The navy is the Coalition's police, after all is said and done.

I am thinking that Earth has twenty "Core" or "Hub" colonies. These worlds, and Earth, make up the major players in the Alliance. I am calling it the "Earth Alliance" right now but that may change. I also like "System Alliance". It's just difficult naming the military forces.

The core worlds control the settler and outport worlds. A settler world is a colony that has not yet established itself as being able to stand on it's own feet without getting critical supplies from a core world. This status is sometimes manipulated ie:settler worlds refused supplies or military support just to keep them as settler worlds, dependant on their core world for the lifelines to the other core worlds and to "modern society". A settler world is not necessarily an uncivilized gun toting place a la "Firefly". In fact settler worlds tend to chafe at the misrepresentation that they are backwaters and want very much to be bumped to "core" status. It is not impossible for a settler world to be upgraded.... it's just rare. But the people running the Alliance are aware that the settler worlds do need the *hope* of obtaining the higher status of a core world. A core world can establish its own settler and outport colonies and grow rich from the raw materials those worlds supply. An outport world is a planet that simply doesn't have a large colony prescence. Control over the environment is spotty. There may be competing Velelvian colonies on an outport world.

Finally there are new worlds yet unclaimed. The Alliance Navy patrols the core worlds, and sends ships to the settler worlds to maintain order. The Alliance Marines are often sent into settler and outport worlds to take down anti-government types before they get too many ideas. Woe to a settler world that decides to go it on it's own. And finally we have the Alliance Explorer Corps. The Explorer Corps tends to maintain order in the outport systems and spends a lot of it's time on scientific missions. They're usually the first to find a mess and the first to see "zones" develope, either in space or on worlds. They have the highest percentaged of "zoned" and "touched" staffers.