We consider the component testing problem of a device that is designed to p
erform a mission consisting of a sequence of stages. Once a stage is over,
the device is overhauled to replace all failed components before the next s
tage starts to improve mission reliability. The components fail exponential
ly where the failure rate depends on the stage of the mission. The reliabil
ity structure of the device involves a series connection of redundant subsy
stems. The optimal component testing problem is formulated as a semi-infini
te linear programme. We present an algorithmic procedure to compute optimal
test times based on the column generation technique, and illustrate it wit
h numerical results.