Nomenclature

A solar sail concept has been developed from a common spiral fold pattern in order to enable a simultaneous mast and sail deployment. This novel concept utilizes the stored strain energy in a series of elastic spar members to enforce proper folding kinematics rather than relying on bulky mechanical joints. The critical inner and outer spar networks are secured to four elastically extendible masts anchored to a central drum. Deployment of the solar sail system is actuated by rotating the central drum around which the masts, spars, and film are wrapped. Tensioned radial cords deterministically unfold the membrane film under the authority of the resilient, spring-like spar members. Proper elastic behavior of the spars is an important facet to this design, and thus a significant effort was dedicated their development. This compact ground demonstration concept includes about 7.5 m2 of reflective membrane film for useful propulsion. Features of this robust, lightweight membrane structure may prove valuable to reducing mass and increasing deployment reliability of other planar subsystems such as sun shades, solar arrays, radiators, or antenna arrays