scope:

Abstract:

The Space Shuttle Orbiter Rudder/Speed Brake (R/SB) Actuators on Orbiter OV-103 were disassembled for inspection after 23 years in service. The actuators had been in service for 23 years and had flown 27 missions; they had been certified for 10 years and 100 missions. The inspection revealed corrosion, pitting and wear to varying degrees, and the four R/SB actuators on OV-103 were replaced with the spares, which had themselves been in storage for 17 years. The use of actuators that had been in storage for a longer period than their certified life led to several concerns, which were duly addressed and the spare actuators were cleared for flight. The possibility of other flight hardware being used beyond its certification limits, whether spares or components that had never been replaced, led to issuance of the Lesson Learned documented herein, which cautions against the use of hardware beyond its qualification and certification limits.