SHEFEX II Precession Control

Abstract

The SHEFEX II sounding rocket vehicle comprised a two stage VS40 motor combination, whereby the first stage was passively aerodynamically stabilized by canted fins but the spinning second stage motor and payload, was repointed before ignition and controlled during its burn phase by a two axis, cold gas, precession attitude control system. The result was a suppressed trajectory with greatly reduced dispersion, which provided a significant increase in the time available for the re-entry thermal protection and canard guidance experiments and improved the possibility for down range tracking and data retrieval as well as sea recovery of the payload.