While Kota Peacekeeper precincts have their own prisons, the worst and most dangerous offenders are sent to THE space prison. It is located above a gas giant.
It resembles two diamond shaped halves connected by a cylinder. It is the size of a massive space station.
The space prison is mostly automated, with most inmates being stored in Cryo Stasis. Each sleeper pod, while connected to the system, has its own emergency power and life support to keep the occupant alive for a short period of time.
Energy comes from the main Plasma Turbine, which uses the gas siphoned from the gas giant below to generate power, seemingly indefinitely.
The prison is meant to be a secret, but numerous individuals around the galaxy know about it. It was built during the early days of the Federation. It has been used to hold various criminals, most of whom are political dissidents, or pirate leaders.
There is no known policy for anyone who finishes their time to leave.