Practical Design and Flight Test of a Yo-Yo Wire-Boom Deployment System

A yo-yo-type wire-boom deployment system has been developed and flight tested on a sounding rocket mission. The goal of the work has been to validate a new mechanism that rapidly deploys wire booms from a spinning spacecraft. This work takes a theoretical system design and implements it in practical hardware. The limitations inherent in practical hardware necessitated new theoretical developments. A modified stability analysis has been developed for the case of nonzero axial separation between the wire-boom base attachment points and the spacecraft’s center of mass. This modified stability analysis dictates that a stable design is impractical for many missions because very large wire-boom tip masses are needed and because the three-dimensional deployment transients are very sensitive to small asymmetries. This problem has led to the development of design criteria and analysis techniques, which permit a short-duration mission to use a slightly unstable nutation mode. These techniques have been used to design a system that has been flown on two daughter spacecraft that were part of a formation of three sounding rocket subpayloads. Each daughter spacecraft deployed four 3-m-long wire booms in under 10 s and maintained a low level of spin instability for the remaining 700 s of the mission. The nutation oscillations showed a slow exponential growth, but the coning half-angles of both spacecraft never exceeded 16 deg.