Space Shuttle Mate-Demate Device (MDD)

The Space Shuttle Mate-Demate Device 

(MDD) at NASA's Armstrong Flight Research Center on Edwards Air Force Base, 

California, is a large gantry-like steel structure that was used to hoist the shuttle orbiters 

off the ground during post-landing servicing 

operations and during mating and de-mating 

operations with the modified Boeing 747 

Shuttle Carrier Aircraft (SCA).

Construction of the MDD was completed 

in late 1976. It was first used during matedemate operations with the prototype shuttle 

orbiter Enterprise during the five Approach 

and Landing Tests (ALT) in 1977. It was then 

used for post-landing and SCA mating operations at NASA Armstrong following shuttle 

orbital missions that landed at Edwards. 

Fifty-four of the 135 shuttle missions landed 

at Edwards between STS-1 in 1981 through 

STS-128 in 2009. 

MDD Description

The facility consists of two 100-foot towers 

with stationary work platforms at the 20-, 

40-, 60- and 80-foot levels on each tower and 

a horizontal structure mounted at the 80-foot 

level between the two towers. The horizontal 

unit cantilevers out 70 feet from the main 

tower units. It controlled and guided a large 

lift beam that attached to the orbiters to raise 

and lower them.

Evening light begins to fade as technicians begin the task of mounting the Space Shuttle Atlantis atop 

NASA's 747 Shuttle Carrier Aircraft (NASA 911) for the ferry flight back to the Kennedy Space Center, 

Fla., following its STS-44 flight 24 November-1 December 1991. (NASA / Jim Ross)
FS-2014-08-014 AFRC

National Aeronautics and Space Administration

Armstrong Flight Research Center

P.O. Box 273

Edwards, California 93523

NASA Facts

Three large hoists were then used simultaneously to raise 

and lower the lift beam. Two of the hoists are connected 

to the aft portion of the lift beam and one hoist is attached to the beam's forward section. Each of the three 

hoists has a 100,000-pound lift capability. Operating 

together, the total lifting capacity of the three units is 

240,000 lbs (120 tons).

Orbiter Servicing

During orbiter turnaround operations, two access platforms for orbiter servicing specialists were positioned on 

each side of the orbiter after it was towed into the MDD. 

The platforms were normally stored at the 60-foot level 

when not in use. During servicing operations, the platforms were lowered on each side of the orbiter by a pair 

of telescoping tubes extending down from the cantilever 

section. Two equipment hoists, each capable of lifting 

10,000 lb. were also built into each tower. These hoists 

operated up to the 60-foot level of the MDD.

 MDD Construction

Connell Associates Inc. of Coral Gables, Florida, designed the MDD. It was constructed in 1976 by George 

A. Fuller Co., Chicago, Illinois, at a cost of $1.7 million. 

A similar but slightly less complex MDD was constructed adjacent to the Shuttle Landing Facility runway at 

NASA's Kennedy Space Center in Florida.

Space Shuttle Hangar

The former space shuttle hangar, near the MDD, is a 

single-bay 25,000 square-foot structure 170 feet deep, 

140 feet wide and 80 feet high. A 6,700 square-foot 

annex on the north side of the hangar building includes 

administrative offices, ground operations control room, 

and a joint-use shop area.

Inside the hangar, two overhead bridge cranes provided 

lift capability for orbiter (or aircraft) servicing and 

maintenance operations. Each crane has a lift capability of 50,000 lb. Voorheis, Trindle, and Nelson, Irvine, 

California, designed the hangar. It was built by Santa Fe 

Engineers Inc., Lancaster, California, at a cost of $3.7 

million. Construction was completed in early 1976. The 

hangar is being retained for other current research projects at NASA Armstrong. 

A concrete tow-way, 60 feet wide and 15 inches thick, 

connects the MDD and the Space Shuttle hangar with the 

aircraft ramp at the main Dryden complex. The taxiway 

extends onto the Edwards Air Force Base flight line and 

runway network.

Space Shuttle Discovery is surrounded by the Mate-DeMate 

Device gantry and ground support equipment during processing for its ferry flight back to the Kennedy Space Center in 

Florida. (NASA / Carla Thomas)

STS-114 Shuttle Discovery is raised for the 747 Shuttle Carrier 

Aircraft to position itself underneath. (NASA / Carla Thomas)