Inertial Upper Stage
Space shuttle
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The Inertial Upper Stage, originally designated the Interim Upper Stage, was a two-stage, solid-fueled space launch system developed by Boeing for the United States Air Force beginning in 1976 for ... Wikipedia
First flight: 30 October 1982
Last flight: 14 February 2004
Lower stage failed: 1
Successes (stage only): 21
Total launches: 24