Assessment of constraints on space shuttle launch rates

The range of number of annual STS flights with 4- and 5-orbiter fleets was estimated and an overview of capabilities needed to support annual rates of 24 and up with a survey of known constraints and emphasis on External Tank (ET) production requirements was provided. Facility capability estimates are provided for ground turnaround, cargo handling, flight training and flight operations. Emphasizing the complexity of the STS systems and the R&D nature of present flight experience, it is concluded that the most prominent constraints in the early growth of the STS as an operational system may manifest themselves not as shortages of investment items such as the ET or SRB, but as inability to provide timely repairs or replacement of flight system components needed to sustain launch rates.