Pioneer

This interesting freeware game is described as "Pioneer is a space adventure game set in our galaxy at the turn of the 31st century.

The game is open-ended, and you are free to eke out whatever kind of space-faring existence you can think of. Look for fame or fortune by exploring the millions of star systems. Turn to a life of crime as a pirate, smuggler or bounty hunter. Forge and break alliances with the various factions fighting for power, freedom or self-determination. The universe is whatever you make of it.

Pioneer is under constant development and has a friendly community of players, modders and developers around it. We release a new version every month. We'd love for you to try it and make part of the galaxy your own!"

http://pioneerspacesim.net/