Best free "space exploration" games

GAME GENRE – Space exploration games put players behind the controls of a spacecraft and give them an entire universe to discover. Rather than following a strictly defined path, these games are often open-ended, allowing players to decide where to go and how to make a living among the stars. Exploration may be combined with activities such as trading, mining asteroids, transporting cargo, fighting pirates, discovering new planets, or simply flying around to see what is out there. Some games focus heavily on realistic spaceflight, while others treat the galaxy as a giant playground for adventure and experimentation. Elite, released in 1984, was one of the earliest and most influential examples of the genre, and its ideas have inspired generations of spacefaring games ever since.