 Prior to launch, a cooler mounted on the outside of the launch tube activates the electrical systems in the missile and supplies cold gas from a Joule-Thomson expander to the missile detector assembly while the missile is still in the launch tube.When the missile is fired, this external connection is broken and coolant gas is supplied internally by an onboard argon gas bottle.The gas is held in a small bottle at high pressure and contains enough coolant for the duration of the flight of approximately 19 seconds.