What about blending this with the idea you've talked about in other threads concerning corporations. You could have things like funding, cost overruns, reputation of companies and maybe even some idea of ethical / unethical behavior (Weyland-Yutani in Aliens) that might have cascading consequence (like smuggling a xenomorph through quarantine). Or a simpler method would be building either science ships or funding a research program. You could do both, making research more expensive but more on demand, as well.
Decisions could be generic or custom to the situation. Generic decisions might involve whether to move or hide the artifact, which could be useful if in alien territory and might have consequences (OnMoved = Destabilizes Star, OnMoved = Triggers Unseen Defender). Custom actions might be things like whether or not to wipe out natives defending the artifact, compensate them, try to use psy-ops to get them to flee the area, send anthropologists to gain cultural literacy (and thus find out what influences them).
Adding something like this would be a chance to give your 4X unique flavor. It could also be an interesting mechanic that helps alleviate boredom, especially early game. There is logically no reason why discoveries can't be made continually, even on settled worlds.
This might take your idea farther afield that desired, but what if you had interest groups that could interact with artifacts? Billionaire collectors could give you money, terrorists could seek to use them as bombs, do-gooder treasure hunters might use them to stop an alien invasion, spies could steal them to start a war. Lots and lots of possibilities, especially if they had a wide range of effects akin to what Avalander described.