Armada 2250: The Rebellion - gamefront.com

Armada 2250: The Rebellion is an action/adventure game in which you play as a lieutenant in the United Space Colonies Navy (USCN). Your current assignment is on planet Pegasus where a small USCN detachment is attempting to stop a band of pirates from raiding USCN trade convoys. However it is only after your base is attacked by these pirates that you begin to realize that it is not merchant ships they’re after, but something far more deadly.