In October 1989, Rockwell International (Space Systems Division) began a year-long contracted effort managed by Langley Research Center to perform an in-depth study of PLS design and operations with the HL-20 concept as a baseline for the study. Using a concurrent engineering approach, Rockwell factored supportable, efficient design and operations measures into defining a detailed, cost-effective design along with a manufacturing plan and operations assessment. A key finding of this study was the realization that while design and technological factors could reduce costs of a new crewed space transportation system, further significant savings would be possible only if a new operations philosophy were adopted which treated PLS in a manner similar to an operational airliner rather than a research and development space vehicle.