Suimar

Suimar was an evil emperor who ruled the galaxy despotically. Generations ago, he built the maximum security prison on RX 338 to imprison all rebels who were against him. Suimar was later overthrown, with RX 338 being used by the Galactic Federation to imprison the most dangerous foes. Samus Aran and Princess Lana were once imprisoned there when Mother Brain's crimes were reattributed to Lana.