Traveller you can do so much, you can be Explorers, Free-booting Merchants,, Mercenaries, Troubleshooters, Troublemakers and so much more. Depends on the GM's and Players wishes.
FASA did adventures based around Archaeology (The Sky Raiders Trilogy), Various Dramas on a Luxury Liner (Action Aboard), Hostage Rescue, Swiping a band pharmaceutical from one group of outlaws for an other group of outlaws, Diplomacy, and a bit of Mercenary work. and FASA was just a licensed third party publisher.
you have 5 GDW/FFE editions to choose from as well as a GURPS edition and a resent one from Mongoose Publishing. Mostly from nostalgia I prefer Classic edition, but that's just me (I have bean gaming for 30 years and It was either Trav or T2K that was my first game).
other games to look at Jovian Chronicles, Space with Giant Robots.
2300AD Adventures against the backdrop of Interstellar war is the main them but you can do other stuff (Exploration, Trade, Troubleshooting, Crime, Espionage and so on).
Space 1889, Steampunk Space.
there are others I'll have to go through my Archives and I'll post the best.