Here are top 4 Sci-Fi MMORPGs.
EVE Online http://feature.mmosite.com/eve/
EVE is a massive multiplayer online game (MMOG) set in a science-fiction based, persistent world. Players take the role of spaceship pilots seeking fame, fortune, and adventure in a huge, complex, exciting, and sometimes hostile galaxy.
Star Wars Galaxies http://feature.mmosite.com/swg/
Star Wars Galaxies is a MMORPG that lets you assume the role of nearly any type of character in the Star Wars universe and interact with thousands of other players' characters as well as established characters from the movies.
Planetsideis http://feature.mmosite.com/planetside/
Planetsideis a Massively Multiplayer First-Person Shooter (MMFPS) game created by Sony Online Entertainment (SOE). In this planetary warfare experience you take up arms as a soldier in one of three ideologically-opposed Empires struggling for domination over the planet Auraxis.™ Fighting beside you will be thousands of other players, relying on your skills, determination, and support to win the day.
Anarchy Online http://feature.mmosite.com/anarchy/
Anarchy Online (AO) is a science fiction themed massive multiplayer online roleplaying game (MMORPG). The first three expansion packs, Notum Wars, Shadowlands and Alien Invasion, have received high praise and won 20 international awards.