Inertial Upper Stage

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Inertial Upper Stage (IUS), originally known as the Interim Upper Stage, is a two-stage solid-fueled booster rocket developed by the U.S. Air Force for the launching of large payloads from either a Titan III (later Titan IV) rocket or from the payload bay of the Space Shuttle.