In twenty-five Space Shuttle flights, NASA has learned valuable lessons which will improve future operations and designs of space launch vehicles. The major lessons learned from Shuttle operations are addressed. Flight operations experience has demonstrated the reusability of the orbiter, the solid rocket boosters, and main engines. However, orbiter ground turnaround time is significantly higher than projected due to expanded refurbishment of some systems and the many engineering modifications required to correct orbiter system design deficiencies uncovered during flight experience. Although reduced by a factor of four since the early flows, orbiter turnaround remains the flight limiting constraint that sets the Shuttle annual flight rate. Similarly, operations experience in flight design, payload integration, and flight controller and astronaut training shows that initial projections underestimated the complexity, time, and manpower required. The principal reasons for this are: (1) the demands of customizing each mission to maximize the science return in a shrinking Shuttle flight program; and (2) frequent changes to the cargo manifest to optimize the mix of science and applications payloads. While experience has reduced the time and level of effort required for these operations tasks, the lesson is clear; performance margins must be preserved so missions do not have to be individually tailored and the cargo manifest must be stabilized to reduce rework of flight and software products.