Does anyone know where i can download a online game like this?

i really like online games but i only find good games with elves and mages and that kinda stuff but i can never find a good advanced technology game(in the future type of game)...i want a game where u can walk around in ur space ship and there are a lot of different planets and u can live on one...do u get a game like this?? if u know any please tell me!!