One of my favorite Savage Worlds settings is Gold & Glory: Seven Deadly Dungeons, where the heroes explore various randomly-generated dungeons looking for treasure -- and one of my favorite board games is Space Hulk, where space marines fight their way through abandoned space vessels. So ever since Gold & Glory was released, I've been pondering using its rules for a sci-fi game, where a rag-tag crew of explorers hunts for salvage among the stars (or perhaps the PCs are a company of mercenaries, or a unit of drop troops, sent on various military missions).
Wild Draw Character Creation
Gold & Glory has some nifty card-based character creation rules. However, for a sci-fi setting (assuming the PCs are not all human) I'd recommend using the species from the Science Fiction Companion instead of the standard fantasy races, and I'd propose handling them with an additional card draw:
2: Aquarian3: Aurax4: Avion5: Construct6: Deader7: Floran8: Human9: Insectoid10: KalianJack: RakashanQueen: SaurianKing: SerranAce: YetiJoker: Choose freely
Similarly, the classes would need to be changed to something more suitable for a sci-fi theme, perhaps including options such as "soldier," "mechanic," "pilot," "psychic," "scientist," "scout," etc.
I'd suggest renaming the currency to something like "galactic credits", and giving characters access to gear from the core rules and Science Fiction Companion. You might also want to pick up a copy of Savage Space (it's free), particularly for the vehicle rules, as the PCs will need a spaceship for their adventures!
The dungeons can be designed in much the same way as Gold & Glory, and there are countless movies and TV shows you can use for inspiration. Here are some adventure seeds (along with their sources of inspiration) to get you started:
Distress Signal: The heroes investigate a distress signal coming from an alien vessel that's crash-landed on a nearby moon. While this plot hook is an obvious nod to Alien, the story could unfold in any number of ways.
Missing Colony: A colony base has gone silent, and the PCs are hired to investigate. Although this seed is inspired by Aliens, the adventure could go in any number of directions -- perhaps the colony's droids turned on them, or maybe the colony was driven insane (like the reavers in Firefly/Serenity).
Breakout: The PCs are hired to break into an automated prison ship and rescue one of the prisoners. Inspired by an episode of the Mandalorian, this adventure could introduce various unexpected twists and challenges related to the ship, the identity of the prisoner, and so on.
Ghost Ship: Inspired by Event Horizon, a starship with a prototype FTL drive vanished on its maiden trip many years ago, and was never seen again -- until a few days ago, when it reappeared, drifting aimlessly through space. The PCs are fortunate enough to be nearby, giving them an opportunity to explore (and loot) the ship before any other vessels come into range.
Alien Outpost: Inspired by the Doctor Who episodes "The Impossible Planet" and "The Satan Pit", the PCs discover a planet orbiting a black hole, with an abandoned base of ancient alien design located on the surface. Who knows what sort of advanced technology might be found within?
Gold & Glory is as much toolkit as it is setting, and the core concept should work just as well for other genres. A horror setting where the PCs investigate dark crypts and haunted houses? A cyberpunk setting where the PCs break into automated factories and military facilities in search of hi-tech loot? A mafia setting where the PCs need to break someone out of a prison, or steal evidence from a police station?
Not every adventure needs to be a dungeon crawl, but sometimes a dungeon crawl is exactly what you need, and the semi-randomization tools provided in Gold & Glory are a great way of handling it.