The translation of a one dimension russ to a two dimensional truss could be executed by adding two tetrahedrons to the octahedron. Combinations of these elements form an octet truss (Figure 9.8a). Polyhedra in various combinations can also form different planar truss structures. Generating a curved truss from a flat planar truss can be accomplished by changing the length of the surface members or changing that of the diagonal members (Figure 9.8b). These planar structures allow for more control and stiffness over large spans as well as ease of deployment and efficiency packaging. Applications to space power could be used in combinations with modular inflatable structures for deployment of large antenna. Figure 9.8 (a) Octet Fold (b) Parabolic Surface Truss [Natori et al, 1986] [Natori et al, 1986] The difficulties with large scale space structures occur because of their size. It is extremely difficult to fabricate, handle, and test these structures on the Earth. Current fabrication concepts are not feasible and thus the realization of many projects are greatly influenced [Miura et al, 1986 ]. Breakthroughs in membrane structures offer solutions to this problem. A combination manufacturing and deployment folding system has been developed by Miura, Natori, and Sakamaki for large planar membranes (Figure 9.9 a,b). Large membranes coupled with deployable supports could be applicable to Space Solar Power Program solar array deployment as well as transmitting and receiving antenna for future space power satellites. Applications of these translate into fewer launches and possible less EVA. This suggest the possibility of a viable Space Solar Power Program in the near future. Figure 9.9 (a) Fabrication Method (b) 2-Dimensional Deployment [Miura et al, 1986] [Miura et al, 1986] Membranes are also applied to inflatable structures. Inflatable surfaces show high accuracy when used as an parabolic shape for antenna and high efficiency in packaging. However their are difficulties with inflatable surfaces. For example reflectors must be manufactured to be one entire structure, and for such a large membrane element, precise accurate manufacturing process and overall handling treatments on the ground are required. Also, due to the lack of internal hard points shape control of the surface is difficult. The larger the surface becomes, the surface root mean square (rms) error increases [Kato et al, 1989]. Modularized inflatable structures (fig. 9.10a) with truss structure supports are projected to be a way of combating these difficulties. Large rigidized inflatables offer several advantages for space applications by good stiffness and thermal stability. Ongoing work is centered on the realization of scaled 3 m. reflectors to be
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