Broad or abstract skills in OSR games don't exist, this is because that type of skill falls under player skill. Ability checks cover niche situations where there should still be some chance of failure, so a roll is needed. I rarely use roll equal to under ability checks myself.
When OSR class skills are employed they apply in specific situations which relate to a specific circumstance in the game. Finding a trap anyone can do. Disarming it is something only the thief can do and only when the trap is located. If the thief succeeds, no one needs to worry about setting the trap off next time they walk past it.
The reason why specificity is important is not so the player knows how to use the skills, but instead the referee knows when a player needs to make the skill check. A referee doesn't have to wait for the thief to say "I attempt to disarm the trap." Instead, the referee says "Thief, do you try to disarm the trap?". Skills are coded into the game.This is important, because that thief player is still able to immerse themselves in the game without having to reference their skill list at all.
If you want to design a skill system in an OSR sci-fi setting, think first about the modes of play that will exist in the game. Thieves fall under the Exploration sub-system. Would an Engineer class be associated with some sort of sub-system that helps to provide knowledge by hacking cameras or computer systems? Does a Pilot class associate with the ability to fly/travel/control drones in a subsystem that centers around ship to ship combat or space travel?
If you are just going to make a massive skill list and let the players work out the best time to use them, that isn't OSR, not to me anyway. I'm not saying a large and broad skill list is a bad thing either. I love the d6 system.