EMU hardware processing, the refurbishment and checkout subset of EMU ground turn-around activities between Shuttle flights, is significantly lower today than it was when EMUs began regular service aboard Shuttle. Despite a significant increase in safety checkout steps resulting from the Challenger accident, hands-on processing time has dropped from approximately 4,000 manhours per EMU then to approximately 1,050 manhours now. The following aspects of hardware maturity contribute to this reduction: EMU hardware problems have been identified and fixed. Flight hardware and ground test rigs were designed or modified to simplify testing, and test procedures were standardized and streamlined. Increased confidence in the hardware allows extension of inspection, service and test intervals. The hardware processing sequence has recently been simplified and implementation is expected to reduce EMU hardware processing time to approximately 600 manhours/EMU in the near future.