The parabolic surface of most large deployable reflectors is formed by a reflective mesh attached to a cable net. This paper presents a new approach to calculate a geodesic tension truss that ensures both appropriate node positioning and uniform tension. It is based on a force density strategy coupled with geometrical constraints. Uniform tension is achieved by iterations on coefficients of force density. Nodes of net are located on the paraboloid by controlling additional forces. Several applications illustrate the method on various types of net patterns and parabolic surfaces. The accuracy of obtained net is then evaluated by calculation of the systematic surface error due to faceting. Attachment of the net to a rim structure with additional cables is also discussed.

A new conceptual design for the architecture of a large deployable space reflector is presented. The reflective parabolic surface is made of a mesh shaped by a cable net and the supporting rim structure is based on scissor mechanisms associated with flexible joints. These joints replace complex articulations while allowing the storage of the energy required for deployment. They also affect the stiffness of the structure and the tension of the cable net. The dynamic behavior was studied by finite element modeling and through tests on an experimental prototype with a gravity compensation device. We focused on the first natural mode, which is an important design criterion for space applications. The measurements are compared to simulation results and we discuss the influence of suspension threads and gravity in the model.

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