Could you clarify which mission this is? When I do a search through foundry missions I can't find one labeled "mirror incursion."
There is about as much water on Earth now as there was three billion years ago. But while the amount of water has remained static, the amount of tequila and Triple Sec available for the making of Margaritas has expanded enormously. So you see, we have made progress after all. ~Anonymous
Another way, if you like (or at least tolerate) DOffing is to basically spam the shipboard development Assignments (Creating hypos, regenerators, shield charges, power cells, ship components ; having your bartended fix you a drink and supply from the special stock) and the Personal and Sector assignments that have 15, 30, 45 minute and one hour times (avoid anything longer if you try this. Exploration star clusters are great for this when they have the "Emergency Supplies" assignment, if you have the necessary commodities (Usually Antigens and Seismic Stablisiser, I think).