The Tunnel Adapter Truss Assembly (TATA) was placed in the Space Shuttle Orbiter’s cargo bay providing an extended pressurized atmosphere allowing the crew to transfer back and forth to pressurized modules in the cargo bay.  A good example would be for Spacelab missions.  The Tunnel Adapter allowed the crew to move from the mid-deck in the Orbiter to the Spacelab module installed in the cargo bay.  An external airlock was part of the Tunnel allowing for spacewalks if required.

The Tunnel Adapter flew on 21 Space Transportation System (STS), the official name for the Space Shuttle, including STS-9, 40, 42, 50, 55, 58, 65, 71, 74, 76, 78, 83, 89, 94, 91, 95, 96, 101, 106, 116, & 118.

The Tunnel Adapter Truss Assembly can be seen in the cargo bay of Space Shuttle Columbia in 1983 in preparation for STS-9.  The Spacelab module can be seen at rear while the tunnel can be seen in the foreground.

STS-9 in orbit with the tunnel in the foreground leading from Columbia’s middeck to the Spacelab module in the back of the cargo bay.

A portion of the tunnel with the airlock attached is on display in the Atlantis exhibit at the Kennedy Space Center Visitor Complex.

People for scale in the foreground give an idea of how large the Tunnel Adapter Truss Assembly is.