During the years of the NASA shuttle program, special 4HW50-75M electric winches were mounted on the top of launch pads 39A and 39B. These units were used to raise and lower the shuttle access platforms into place when required.
NASA SPACE SHUTTLE PLATFORM WINCHES
Thern supplied the winches required to raise and lower ET Orbiter access platforms on Space Shuttle pads 39A and 39B. Winches were supplied with grooved drums, limit switches, and redundant braking.
Because of the hazardous environment with salt air, the winches were epoxy coated.
The platforms will be locked out when in position prior to supporting personnel. Winches were supplied with two-speed motor to allow for high-speed movement and low-speed positioning.