Endless Sky

Endless Sky is a sandbox-style space exploration game in the vein of Elite and Escape Velocity. You start as the captain of a tiny spaceship and choose your own path: trade goods between star systems, carry passengers, take missions, hunt pirates, or take sides in a civil war.

A major plot line runs alongside many minor missions, but you can ignore it and strike out as a merchant, bounty hunter, or explorer. Earnings buy a better ship or upgrade the weapons and engines on the one you have, and the game's data files are openly moddable.

Endless Sky runs on Windows, macOS, and Linux. The source code is GPL v3, while the artwork is public domain or released under Creative Commons and similarly permissive licenses.