Belt and Suspenders
NASA apparently plans to have a second shuttle at the ready in case anything goes wrong during the next mission.
Astronauts could use the space station as a “save haven” [sic] if there is trouble with the orbiter while it is in space, said Michael Kostelnik, NASA’s deputy associate administrator for the space station and shuttle programs.
“The second vehicle would be able to launch and go to the space station and pick up the first crew if we had a problem with the vehicle and could not bring it down,” Kostelnik said in a briefing from Galveston, Texas.
What if it does? Can they actually dock two Orbiters to ISS? Could two Orbiters with docking adapters mate with each other for crew transfer? (Is the androgynous docking adapter that, uh, “open minded”?)
More info here on Shuttle safety upgrades.