scope:

Description of Driving Event:

The payload bay bridge hoist system is located in the orbiter processing facility, and spans the length of the shuttle payload bay. The two bridges, mounted on platforms, move on rails. On each bridge are two movable trolleys, each providing a base for a suspended telescoping bucket hoist. Maneuvering to any point in the payload bay is possible with the three directions of motion provided by the bridges, trolleys, and buckets. With no mechanical locking device to support the bucket load when cables are disconnected for inspection or replacement, a possibility exists for damage or injury.