Quote: meshoo
10 ships from every kind of ships ??!!
As developers told me, you need to have ships of the type you want to control. For example, you have sent 5 Fighters and found some more. You then get a random percentage from 1% to 100%. It is upgraded by some factors like your Expedition Technology level and expedition duration. The final percentage is applied to amount of ships of given type in your fleet: in our example it is 5. If the percent was lower than 20, your fleet of 5 Fighters won't get new ships.
In the worst case you'll need 100 ships to guarantee that 1 new can be controlled, but with higher technology level and mission duration you'll need much less.