Sliding Core Deployment Mechanism for Solar Sails based on Tubular Shell Masts

Abstract

The paper describes the design of a solar sail deployment mechanism for flexible, tubular shell masts of closed cross-section. The mechanism is based on a novel interface design between the mast and its deployment mechanism that enables an interconnection of high stiffness and high load carrying capability. The interface is designed similar to an extrusion nozzle consisting of a core that is sliding inside the boom and a support shell that is enclosing the boom. As the boom has a closed cross-section, the core is held contactless in position from the outside by an enforced form closure using the flexibility of the boom shell. Between core and enclosing support shell remains only a small gap whereby any lateral motion of the boom shell is prevented. This enables a stiff connection and good load transmission between boom and deployment mechanism which results in a high overall performance. Lateral bending tests show that the bending strength of the mast around its weak axis is increased by 90% through use of this interface while bending stiffness increases by 23%. The paper describes the mechanical principle of this sliding core interface and presents an overview of a mechanism prototype for solar sails and similar applications.