The following are the key planets involved in USOP activities...

Often used a a military base, and also for research, as Mars has many good libraries with valuable documents. Olympus Mons is currently being alterred to shelter refugees and those in need, and also has a flea market.

Saturn is where a large amount of weapons and vehicles are stored and produced. Many ingenious minds there are currently at work on Kiwi cars, and portable microwaves for inter-planetary workers without time to go home for dinner. There is also a nice inn on Saturn where you are welcome to spend the night.

Uranus is closely watched and guarded for the protection of Hose Woman. Its rebellious spirit raises many useful spies, and is basically a hideout for outlaws in league with the USOP.

Pluto is a nice place for people to run laps, but more importantly, Pluto constantly generates MagmaB27, which is sent to Saturn and Mars in generous amounts.

Jupiter is not a member of the USOP and is where the enemy festers. Jupiter is not helpful and not a tourist attraction in the least. Says the Queen of Saturn, "jupiter is not in any way part of the usop. in fact, it is part of the usoap (universal society against peace). If you enjoy being hit on the head by over-sized hockey pucks while walking under a building, being sprayed qith shaving cream while sniffing flowers, and never EVER being told "have a nice day" when shopping for socks at the local drug store, then this is definitely the place for you."