OK It took me a long While to get this Acheveiment... But I have found an easy way to help you get It. Ok In case you did'nt know the actual process starts on chapter 4 when you have to get into the ships ADS cannon. What you have to do: You have to defend the ship while your partner reboots the automated firing system. Ohh and did i metion your defending it against speeding astroids?? It takes a good 2 and a half minutes to complete. Ok try first by focusing only on the middle. i am not saying to completley forget about the sides but the astroids in the distance to the left and right most of the time fade off and never even hit the ship. (TIP) try using only one firing pin because if you use both the gun might overheat and then you are in serious trouble. When you see a massive boulder coming your way send a volley of shots to avoid the debris hitting the ship. Also turing down or muteing the T.V Really helps on concentration Trust Me! Do not panic. you tend to aim off when you panic. try to keep the integrity to about 70% and you will feel confident and not overheat. So with the volume down and your concentration take out all the astroids far off. the closer they get the faster they get (i dont know thats just how it is) I should have metioned this before but save before you try this considering it may take a couple trys...there is a save point right when you enter the room. When i finally did this i had 51% so yea. but after I did what i told yo i finished with 71% Ok so... Stay focused, turn the volume down, Do not and i repeat do not panic!!, Save!, and pick them off from a distance. And difficulty does not matter. I did this on impossible so yea. Well I hope this helped And If anything i would do it for you but IDK you feel better knowing you did it yourself.