You may have seen those promotional videos or photos of modern cars being prototyped in a designer's studio--the look and shape of a car is tweaked not only on a computer screen, but on a physical models made of wood and clay. It's not only car manufacturers that craft life-size mockups of vehicles before going into actual production--NASA does it too! Considering that each Space Shuttle Orbiter cost contractor Rockwell Corporation (now part of Boeing) $1.7 billion to manufacture, a model for design and equipment testing purposes makes *some* sense. Art designer Aaron Harvey inherited two rare photographs of NASA's mock Shuttle of from his grandfather who worked at Lockheed in 1975. According to recollections from engineers who worked on the Shuttle project, the full-scale mockup was made to sell NASA on the design of the Orbiter for Rockwell to secure the contract to build the real thing. As you can see from the photo below, the payload bay doors fully opened up, allowing engineers to test what type of cargo and equipment NASA could bring on the STS-1 mission. The mockup still currently resides in the NASA-Rockwell facility in Downey, California (close to Los Angeles), and was restored for preservation in 2003. This PDF documents the extensive restoration process and includes more rarely-seen photos of the wooden mock-up, including its relatively detailed interior.
The Downey mock-up isn't the only faux Shuttle Orbiter in existence. NASA commissioned other scale models for training and testing purposes, and aviation museums have been clamoring to host them since the decommissioning of the working Orbiters.
Pathfinder, for example, was a simulator originally built in 1977 for size and weight fitting. NASA used it to check roadway clearances and crane strength, meaning that it had to be the exact size and weight of a real Orbiter. After spending some time on display in Japan, the Pathfinder returned to the United States and now resides at the US Space & Rocket Center in Alabama.
The Space Shuttle Explorer is another full-scale mock-up, but one built much more recently in 1993 by contractor Guard-Lee using Rockwell's original designs. Explorer was built primarily for display and educational purposes--visitors could actually go inside the replica to tour the payload bay and crew cabin. It's home was the Kennedy Space Center Visitor's Center until last December, when it was moved to Houston's Johnson Space Center to make room for the Atlantis. By some accounts, Houston's space fans are not happy with the move, which they consider a poor consolation prize for not being awarded one of the actual Orbiters for display.
Houston's Johnson Space Center previously housed the Space Shuttle Full Fuselage Trainer (FFT), another Orbiter replica that built in the 70s as a testbed for Shuttle upgrades and a vehicle for training astronauts. The wingless model has a detailed interior, which helped astronauts familiar themselves with the layout of Orbiter equipment and controls, as well as living quarters. Like the other mockups, it too is made mostly of wood instead of metal. The FFT has been relocated to Seattle's Museum of Flight.