Space Launch System Program (SLSP) Lgistics Support Analysis (LSA) Report 26 April 2013, NASA
Page 14 of 149: "Given the SLS Block 1 launch processing manifest (4-5 years with little to no activities), there is a potential of not having sufficiently trained personnel. Issue - Yellow (May require personnel with advanced skills not readily available)"
Page 8 of 111: "The developmental approach for the SLSP, consisting of 2 exploratory missions years apart, followed years later by the operations phase, presents unique logistics challenges."