Board the freighter and you will come across a weapons locker next to a watertight door. A control panel to open the next door will also be in that small room.

Before operating the control panel, equip the Dethex Launcher and use the secondary function to put a guided grenade (push the X button to jump) through the grate maze in the wall and floor of the room.

Use the bomb to blow open the locked watertight door. Inside, you can get a weapon tech pick-up and revert a message for this trophy.