The Central Galactic Space Forces, also called the Spacy, is the space warfare branch of the Armed Forces of the Central Galactic Union. It fields millions of warships, logistics vessels, and fighters, making itself the largest space force in the history of the Galaxy. It is used to to defend the Republic's citizens at home and abroad, to project military power of the Republic in foreign space, and to enforce the space-maritime law across Union space. Its stated mission is to “maintain the sovereignty of the Central Galactic Union in deep space, outer space, and high orbit”.
The CGU Spacy was formed from the various space-naval traditions of the human states of the ISTO and the Confederacy, but primarily draws its identity, organisation, and traditions from the Terran Imperial Space Navy. The Spacy is administered by the Department of the Navy, alongside the Central Galactic Navy and the Central Galactic Marine Corps, and as such is headed by an appointed civil servant, the Secretary of the Navy, and by an Under-Secretary for Space. It is professionally headed by the Chief of Space Operations, statutorily holding the rank of Supreme Admiral, who is also a member of the Joint Military Staff. It contains over 4 trillion active-duty and 4 trillion reserve servicemembers, deployed across one million capital combat spacecraft. over forty million crewed support spacecraft, and over eight million space defence stations. It is second only to the Army in terms of manpower.
The Central Galactic Space Forces, also called the Spacy, are a section of the colloquially named "Naval Service", constituting several service branches that share a common lineage with Earth's naval warfare services. The Spacy is administered under the Department of the Navy within the Ministry of War. While the Department of the Navy as a whole is headed by the Secretary of the Navy, a subordinate secretary handles matters involving the Space Forces, the Under-Secretary for Space. The Space Forces are headed professionally by the Chief of Space Operations, an active-duty flag officer who is the chief adviser on Space Forces matters and chief advocate on the Spacy's professional, technological, and operational development. The CSO is statutorily an officer of the rank of Supreme Admiral, and serves also on the Joint Military Staff, an agency of the Ministry of War composed of the service chiefs and joint high commanders who provide, under the guidance of the Chairperson of the Joint Staff, advice on military matters. The Space Forces are headquartered at the Johnson Space Center in Houston, Texas. The Department of the Navy has its offices in The Pentagon in Arlington, Virginia and at Edo Castle in Tokyo, Japan.
The Spacy is divided operationally into Major Commands: Expeditionary Space Command, Space Defence Command, and Orbital Defence Command. These commands are held by Major Commanders, statutorily officers of the rank of Chief Admiral (O-14). They serve as the organisational and strategic planners for their areas of responsibility, and are subordinate to Joint High Commanders for their areas of responsibility, where applicable. Expeditionary Space Command provides training, technology, and organisation for all expeditionary space forces assigned to Joint Forces Command, and its commander is the Space Forces deputy to the Joint Forces Command staff. The Strategic Space Command is the deputational command to the Joint Strategic Command. The Space Supply Command is the deputational command to the Joint Logistical Command, and provides training, readiness, and materiel for logistics and supply spacecraft and transport points. The Space Forces also provide personnel and operational capacity for the Naval Special Warfare Command, Naval Medical Service, and the Naval Chaplain Corps.
In addition to these, there is a Major Commander for each of the 82 geographical Combatant Commands with operational oversight of the Space components to the joint commands. Each of these control a different amount of personnel, with the "operational building block" being a Flotilla of several hundred capital spacecraft and several thousand support craft, both manned and unmanned. Such groups are tasked with the defence of an entire star system; the average Combatant Command possesses at least a hundred active Flotillas, combined into a Fleet, and correspond to one of the Sector-level governing units of the Union. Some have more, if they are deemed particularly strategically significant. These Combatant Commands also operate over eight million crewed deep-space and orbital defence stations of varying sizes and crew considerations, some of which require only two personnel and some of which require as many as a battleship. They are all operated as defence forces for these geographical and stellagraphical regions.