If you are multiplayer game, if your allies have found space ponies, ask them to desert that planet and then colonize, don't research any of the planetary upgrades but do the exploration (usually if there is an artifact, it will show up after the first level) then re-abandon it back to your ally. If enemy target only that planet only, if you have ships exploring if an enemy has found an artifact, it will show up on your alerts and you can see where it is.
Although you can do the same for a single player game, only don't have any allies, then you can attack any planet at your discretion
