Pyrotechnic Control

Attached to the underside of one equipment bus compartment was the box containing the control electronics that arm, disarm, and fire detonators to activate various explosive bolts, pin-pullers, and other devices. This subsystem enables release of the solar panels from their stowed position after deployment from the shuttle, actuation of propulsion valves, ignition of the SRM, and separation of the spent SRM after orbit insertion.