Continuous habitation of a space station is a bit historically unusual. Skylab had three visiting manned missions, none of which overlapped. Early Russian stati

Continuous habitation of a space station is a bit historically unusual. Skylab had three visiting manned missions, none of which overlapped. Early Russian stations operated similarly. Mir was operated more like ISS, but left unoccupied several times. (See http://en.wikipedia.org/wiki/Soyuz_TM-30 http://en.wikipedia.org/wiki/Soyuz_TM-30 for a commercial mission to revive and try to restore the previously-abandoned MIR.) And the ISS (or early parts thereof) went about two years before its first long-term crew. So, yes, you can get back into the ISS if it's empty. That capability has been designed into both halves of the space station from the beginning.