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
Rendezvous: A Space Shuttle Simulation Rendezvous: A Space Shuttle Simulation Rendezvous: A Space Shuttle Simulation, is a space simulator published 1982 by Edu-Ware, and developed by Titan Computer Products and NASA scientist Wesley Huntress. Accompanied by a thick "Spacecraft Operations" manual with a chapter on use in the classroom, this flight simulator was marketed as being as educational as it was fun to play. The simulation is centered on a typical Space Shuttle mission to service a space station. Mission phases include "Earth Lift-Off", "Orbital Rendezvous", "Approach" and "Alignment and Docking". It was released for the Apple II in 1982 with positive feedback from reviewers.