S-Series · Japan Aerospace Exploration Agency
S-Series is a fleet of sounding rockets funded by the Japan Aerospace Exploration Agency (JAXA) that have been in service since the late 1960s. Manufactured by IHI Aerospace and operated by the Institute of Space and Astronautical Science (ISAS). The nomenclature of the S-Series rockets is the number of "S"s indicates the number of stages, and the following number details the diameter of the craft in millimeters. For example, the S-310 is a single stage rocket with a diameter of 310 mm.