Cable Resistance in Spacecraft Deployable Mechanisms

Abstract

The resistive torques of cable harnesses and service loops comprise a significant portion of the force budgets of deployable space mechanisms. The space engineering community lacks a reliable and methodical way to predict these forces early in the mechanism design process. Incumbent methods rely on estimates from heritage applications or use deployment prototype tooling. The latter approach is typically specific to the application and the design and therefore incurs timely and expensive iterations. This paper describes a methodology for directly predicting cable drag and resistive torque from the cable specification and deployment geometry alone. The method outlines a standard procedure for characterizing the elastoplastic and viscoelastic material properties of space cables. These experimentally-determined material properties are supplied along with deployed cable geometry to a FEA model, which predicts the cable resistive forces in a representative deployment system.