Missile technicians operate and maintain the UGM-133 Trident II D5 missile Strategic Weapon System (SWS) carried aboard ballistic missile submarines and at strategic weapons facilities. Missile technicians operate and maintain electronic, mechanical, hydraulic and pneumatic strategic weapon subsystems, test and operate the MK98 fire-control system and MK 6 guidance system, perform classified targeting operations, and provide physical security to nuclear weapon systems.