|The Mate/Demate Device is in the midst of the most extensive overhaul of its 28-year history. As part of the effort, lead-based paint will be replaced with a fresh coat of nontoxic paint. The project is progressing safely and with respect for the environment. In fact, a team of contractors and NASA personnel collaborated to develop a method for disposing of 240 tons of lead-based paint being removed from the structure by recycling it into commercial cement rather than sending it to a landfill as hazardous waste. The project is expected to wrap up this summer. The MDD has been modified as the needs of the Space Shuttle program changed, requiring welds, concrete and additional work platforms and greater lift capability.
NASA Photo / Tony Landis
MDD's history spans 27 years . . .
and 49 shuttle landings
By Jay Levine
About a year before it would hoist Space Shuttle prototype Enterprise onto the NASA 747 for the first time, the gargantuan steel structure called the Mate/Demate Device (MDD) was built and ready to do the heavy lifting.
The structure has served NASA well, as Dryden was the primary landing site during the early days of the Space Shuttle program. It remains the primary backup landing site when clouds roll in at the Kennedy Space Center, Fla., and the weather isn't good enough for a landing there. In all, 49 Shuttle landings took place at Dryden, including the first nine Orbiter flights, minus STS-3, in which Columbia landed at White Sands, N.M. That 49-flight total also includes all of the first landings of new Orbiters as each joined the fleet.
The MDD consists of two 100-foot towers with stationary platforms every twenty feet from 20 to 80 feet on each tower and a horizontal structure mounted at the 80-foot level between the two towers. The horizontal unit cantilevers 70 feet out from the main tower units, guiding and controlling a large lift beam that attaches to the Orbiters to raise and lower them.
Three large hoists are used 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. The three hoists operate simultaneously. As a unit the hoists can lift 120 tons, or 240,000 pounds, and the average Space Shuttle weighs in at about 231,000 pounds, said Joe D'Agostino. D'Agostino, originally hired as a Shuttle security officer, now heads Dryden's Space Shuttle operations. He recalled the first time the device was used.
"The first time we lifted (Space Shuttle Prototype Enterprise) during the ALT (Approach and Landing Tests) program took a considerable amount of time, which is to be expected with a new operation," D'Agostino recalled. "We had a technical problem (mating Enterprise). The operation lasted almost 14 hours. We got it to the point where we were ready to lower Enterprise onto the 747 and we learned the Orbiter didn't fit.
"To make it fit, we moved the forward strut on the 747. It was nerve-wracking because it didn't fit."
The second time Enterprise was lifted was much more streamlined and the effort took just six to eight hours, he said. Shuttle landings later required changing work schedules in order to keep staff on site around the clock, until the Orbiter was safely mated to the NASA 747 and on its way to Kennedy Space Center.
Retired MDD inspector Ski Markey said Dryden worked extensively with staff at Kennedy on the construction of the one-of-a-kind device. He also explained how the device was proven.
"To make sure the weight of the Shuttle would not pull the MDD out of the ground, we had three concrete blocks that simulated (the Shuttle's weight). It looked good to us," Markey said.
During the ALT flights, the biggest fear was that the two aircraft would come together when the Enterprise separated from its host, but for D'Agostino, Enterprise's overland trip from Rockwell International's (now Boeing's) Space Shuttle facility at Palmdale's Air Force Plant 42 to Dryden also was nerve-wracking.
"One of the scariest parts for me personally was watching some of the tiles that fell by the road. We picked them up. Some were flight tiles, some were not flight tiles. We later reinstalled all of them at Dryden," D'Agostino said.
When the MDD was completed in 1976, so too was the Area A Space Shuttle hangar, near the MDD - 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 also was available for administrative offices, a ground operations control room and a joint-use shop area. The contract for Space Shuttle Area A facilities was let by Kennedy and coordinated on site by Dryden. The NASA 747 aircraft (there are two) are assets of Johnson Space Center, Houston, with one based at Dryden and maintained through a contract with Dyncorp.
D'Agostino said the approach and landing tests were different from working on the operational Shuttles that went to space. However, Dryden had personnel with the background and skills necessary, in a number of disciplines, to coordinate the around-the-clock support the Shuttle program required.
"You had Jim Phelps, Gary Trippensee, Chuck Brown, Herb Dorr, Mike Arebalo, Jim Edgeworth and a whole team of other people. Ike Gillam (director of Space Shuttle operations for Dryden during the ALTs and later deputy director, acting director and director) helped Dryden understand its space role. Dennis Bessette was a deputy, and Richard Day engineered a lot of things we did and had them built by our sheet metal shop. Most of the engineering on the MDD came from Florida. Contractors also were responsible for convoy trucks, a task now handled by (United Space Alliance, primary Shuttle operations contractor)," he said.
Dryden's MDD is more complex than the one at Cape Canaveral, D'Agostino said, because this device is used at Dryden for doing work that when it is necessary in Florida can be accomplished at Kennedy's Orbiter Processing Facility. The structure is similar to its Florida twin, but the Dryden MDD has elevators and had extra equipment required in the early days of the program. Dryden modifications were made largely to enable the device to meet heavy-lift requirements as the Shuttle program progressed.
"A lot of NASA centers helped us including Goddard Space Flight Center, Marshall Space Flight Center, Johnson and Kennedy. It was a real team effort. There was a lot of excitement," D'Agostino remembered.