You can get this in Chapter 3 when you enter the ship after you first spacewalk when the Eudora blows up. After entering you open the doors for your teammates then enter the room they are in from here you go to the next room which has a Work Bench. On the wall right next to door you just came through is a circuit panel (blue circle of light on the panel) walk up and collect the circuit. Now go to the Work Bench and install it into whatever weapon you want. Trophy Pops. Pretty easy.