Starflight 2: Trade Routes of the Cloud Nebula (1989 by Binary Systems, published by EA) is a brilliant game that combines space exploration, role-playing, and strategy in a futuristic setting. The game world includes around 150 solar systems, each of which contains between 0 to 8 planets ranging from inhospitable gas giants to habitable Earth-like worlds.
Starflight 2 has a cult following to this day, though it wasn't received with just positive reviews when it was first published. If you were patient and "nerdy" enough, the game unfolded its vast universe, but the learning curve was steep, and so the game was often deemed too hard by the more casual gamers.
It was originally published for IBM PC compatibles in 1989, ports to the Amiga and Mac by MicroMagic were released two years later in 1991. By the weay, the in-game year is 4639, so if anyone still plays this game in 2614 years from now, they might have a chuckle...
(Note: I couldn't get the sound to work so I used the "Major Tom" sond from Peter Schilling, which is probably more known to the German audience than anyone outside of Germany.)