As Star Trek Online has evolved since Discovery missions were added to it, however those changes haven't been without some cost. The Arena of Sompek was removed from the game as a long running event. However, starting on August 8th, the Arena is coming back and you could just win yourself a new ship.
From August 8 through the 29th, the Arena of Sompek has been reactivated, giving players a chance to win a new Tier 6 ship. You'll battle through seven waves of enemies and defeat a boss to win your reward. This is the third and final event if you're pushing for that new Tier 6 vessel. You'll have to complete wave seven in order to get your TFO Commendation and coupon progress tokens.
Once the event is over, the Arena will be sticking around as a scalable event for the bravest captains to try their hand at completing. For more information about rewards and availability, check out the official announcement on the Star Trek Online website.