U.C.N. The United Corporate Nations

"Corporation, noun: An ingenious device for obtaining individual profit without individual responsibility." -Ambrose Bierce
The United Corporate Nations is an economic and political union or confederation of hundreds of Corporations which are located primarily on Terra (Earth), Mars, and Venus. The UCN was founded 150 years ago after the Great Price Wars of 2050, to stop future wars between corporations, and to provide a platform for dialogue. It is the largest human-run government in the Galaxy, and the primary motivator for exploration.
Though each member corporation is its own sovereign state, the UCN as a whole is managed by the Executive Board, which is comprised of representatives of the 12 largest and most influential corporations. Under the board are a vast horde of representatives from the other member corporations of the UCN, who continually lobby for their own corporations and interests. This chain of command filters down to a complex bureaucracy comprised of career politicians who are widely thought to be protocol-obsessed, petty, small-minded, arrogant, ignorant, cowardly, and notoriously corrupt. But somehow it all works.
The primary concern of the UCN is to make sure that all member corporations adhere to the legal trade standards of the UCN. To ensure these policies are maintained, the UCN employs an army of Diplomats, Lawyers and assorted pencil-pushers who are the dread of all hard working people across the galaxy.

PLANETS
The center of the UCN is the Sol System, though as mankind spreads farther into the Reaches, the grip of the UCN and the relevance of Mans Home Star remains to be seen. As for now however, the following worlds are the home of most of humanity:

Terra (Earth)
The birthplace of humanity and official seat of the UCN Executive Directorship Board. This world is covered in a nearly continuous, vast city. The only exceptions to this vast panorama of city, factories and roadways are the many polluted waste zones that dot the planet. Terra is home to teeming billions of humans, with the wealthiest occupying the highest towers, with the poorest living in grim warrens on low levels or in the wastelands.
Even the Terran seas host floating and sub-surface cities, though most of these are dedicated to the growing, harvest and processing of assorted food algae. The world's natural fauna is dominated by rats, flies, cockroaches and canines, while plant life is composed largely of weeds, cacti and other wild desert plants. Other animals and plants are only to be found in zoos, labs or as exotic pets. All but the wealthiest here live short lives, aging quickly in a toxic environment. Small wonder that here was born the hunger to explore and conquer the cosmos.

Mars
This dry planet was terraformed by land and resource hungry Terrans over a century ago. This world now has its own ecosystem, including genetically engineered animals. Mars is dryer and colder that Terra, but is comfortable for humankind and Terran animals and plants. Many species long extinct on Terra are thriving species here, though they are physically adapted to the lower gravity such as the gracile elephant and megaparrot (see examples). Terran bats in-particular have adapted well, growing to a wingspan of eight feet.
Martian-born humans possess a zest for life that is unmatched anywhere else is the Sol system. They are characteristically tall, thin people with pale complexions and large eyes from generations in the lighter gravity of Mars.

Venus
This jungle world was terraformed around the same time as Mars, and boasts a genetically engineered ecosystem reminiscent of Terra's prehistoric past. The world itself is largely covered with a shallow sea dotted with thousands of islands. The three continents named Phoebe, Ishtar, Labda and Aphrodite (see map). Ishtar and Labda are temperate while Aphridite and Phoebe are both tropical, though kept from growing too humid by steady ocean breezes.
The people of Venus are energetic, passionate people known for their boisterous festivals. Art. music and dance are great passions here, and the planets cities are always bedecked with elaborate artworks.

Other Worlds
Sol System hosts numerous smaller colonies, from orbital space cities to domed colonies amongst the systems smaller planets, asteroids and moons. Several of note are:
Astropolis: This is a massive space city located at the Lagrangian Point L2 between Terra and Luna. It is the oldest of such "space cities" and quite famous.
Ceres: This dwarf planet is located in the Sol Asteroid belt, and so has been extensively colonized in the 2100s as a main base and transport hub for future asteroid mining infrastructure. Now it sports extensive domes that cover the entire planet.
Io: One of the moons of Jupiter. A rocky world, by the 2100s Io has been colonized by humans who have built domed cities in order to create a suitable atmosphere for living. This is a wealthy world, ruled by Olympus Mining Industries.
Luna: The moon of Terra was the first major colonial effort of Terra, and thus is extensively developed. The majority of the colonies on Luna are underground, and are extensive.
Mimas: Mimas is a moon of Saturn which is also sometimes called Saturn I. Mimas was colonized by humans by the mid 2100's and became a popular holiday destination for spaceship crews and civilians alike. Mimas is corrupt, overcrowded, and has a high crime-rate. Traffic Jams were so large that deaths aren't uncommon due to starvation.

LAW AND ORDER
All corporations maintain their own security personnel, with mercenary armies are commonly used when operating in the Reaches. But closer to home (Sol System) and along established UCN trade routes, it is the UCNP (United Corporate Nations Police) holds jurisdiction.
Overworked and underpaid, these police guard the peace enforce trade rules wherever numerous corporations are active. Clashes between corporate security personnel and UCNP are legendary, and often true. So the lives of these brave men and women are rarely dull.
UCNP are distinguished by their uniforms and riot armor. Armed with riot guns, stun batons (sonic mace) or other light armaments. Distinctive police vehicles, weapons and armor are readily available to UCNP operative, with conditional access to heavier weaponry, such as mortars, powered armor and armored vehicles.
The UCNP also maintains a large fleet of relatively outdated vessels to patrol their territory. Most of the fleet consists of Class 1 Fighters and Class 2 Scouts, though larger craft do exist.

THE UCN AND YOUR CAMPAIGN
Player characters in operation anywhere near the Sol System or in UCN controlled regions will have to deal with some aspect of the UCN eventually. Staking a mining claim, collecting State bounties, registering planets, or similar concerns require dealing with the UCN.
The UCN and all of its aspects is a monolithic, bureaucratic nightmare. Such government personnel are notoriously corrupt, with the rare helpful representatives delegated to lower tiers of influence. On top of all of this, the UCN is VERY powerful, and capable of making all but the mightiest corporations quake.
Try to imaging any unpleasant experience of dealing with government bureaucracy, such as the DMV, IRS, the UN or any number of legal claims departments, and fill it with corrupt officials in most managerial levels. Now elevate that to a solar-system wide supra-governmental level.
Thats right. Welcome to the future...