The Polities

The first important thing to note about the player teams is that everyone is human. At the start of the game there were no known sentient aliens resident anywhere in human space - and the evidence for their existence anywhere else was circumstantial at best.
Official name of the polity 'known as..' 'National Characteristics' (2) Size and power
Greater Federation of Asteel (GFA) Esteelers Democratic, freedom-loving, a bit inefficient. Politically and socially bit like present-day America Major
Mars Association of Free Colonies (MAFC) Martians Independly-minded, loose association of freedom-loving colonies. Famous for being relaxed (like Australians) and for having very efficient military. Major
The Centauri Conglomerate Centauri Heavily economically based, capitalist system. Profit-motive is strong. Believers in very small government. (eg even it's star-fleets are sub-contracted). Have a pathalogical hatred of robots. Minor
The Earth Empire (1) Earthers The oldest and strongest polity. Famous for its traditions and alleged arrogance (think 19th century British Empire). Major
The Republic of New Venus (RNV) Venerians Young and some say aggressive polity. Famous for it's high degree of centralised control (think - Soviet Union). Major
The Sirian Socialist Republic (SSR) Sirians Highly bureaucratic and internally politicised polity. Makes very extensive use of robots (to whom it has given limited legal rights). Minor
The Union of Xyon (UoX) Xyonists Small, strongly commercial and trade based polity. Has strong links with the GFA. Famous for its intelligence services. Minor
The Wolf359 Commonwealth Wolfers An older polity with long traditions. Fairly close-knit and insular. Has a Royal Family. (Think - present day Britain). Minor

Notes
(1) Constitutionally the Earth Empire is actually called 'The Solar Republic' - but this term is practically never used.
(2) These are grossly over-simplified stereotypes - the actual character of a polity of billions of humans is obviously much more complex than that.