This is an idea for an artifact to also help with getting more planets for the higher ranks without breaking the game.

The artifact would move the target planet to a different list as for colonies. This compacted planet list would have the advantage of taking it off your main list, but a down side of they cannot be alerted but once a week.

Well or some other down side. The Encrypted planet colony list might make it easier on the players getting planets, but it will also make it harder for them to keep them over the long run. This would be a boost and a risk.