While on the freighter, look for a weapons locker next to a watertight
door. Locate the control panel that is in the same room and opens the
next door. Equip the Dethex Launcher before using the control panel.
Jump and use its secondary function to place a guided grenade through
the grate maze in the wall and floor of the room. Explode the grenade to
open the locked watertight door. There is a weapon tech pick-up and
message inside that unlocks the "Mother My Brain Hurts" achievement
after it is read.