Space Shuttle Columbia that remained fitted to the avionics suite, and an internal airlock that, originally fitted into the other orbiters, was later removed in favor of an external airlock to facilitate Shuttle/Mir and Shuttle/International Space Station dockings. Due to its weight, "Columbia" could not have used the planned Centaur-G booster (cancelled after the loss of "Challenger"). The retention of the internal airlock allowed NASA to use "Columbia" for the STS-109 Hubble Space Telescope servicing mission, along with the Spacehab double module used on STS-107. Due to "Columbia's" heavier weight, it was less ideal for NASA to use it for missions to the
Space Shuttle orbiter Space Shuttle orbiters were assembled at Rockwell's assembly facility in Palmdale, California, at the federally owned Plant 42 complex. In addition to the test articles and orbiters produced for use in the Shuttle program, there are also various mock-up replicas on display throughout the United States: Space Shuttle orbiter The Space Shuttle orbiter was the spaceplane component of the Space Shuttle, a partially reusable orbital spacecraft system that was part of the Space Shuttle program. Operated by NASA, the U.S. space agency, this vehicle could carry astronauts and payloads into low Earth orbit, perform in-space operations, then re-enter the atmosphere