4.2 .3.1 Background Some test data has been generated in the low thickness ranges and are summarized in the NASA Handbook of Structural Stability. However, the thickness does not extend in the ranges expected for the antenna structure; in addition, various materials should be evaluated such as the graphite/epoxy, Kevlar 49/epoxy, etc. 4.2 .3.2 Desired Output Local instability design curves as function of parameters such as section geometry, initial imperfections, materials properties, applied axial compression load and temperatureload time histories. 4.2.4 Design Environments A study of all the structural design environments induced on the antenna during launch into low and synchronous orbit is necessary. This study should establish the design conditions induced during fabrication and assembly in space, with consideration being given to the 30-year life requirement. 4.2.4.1 Background No data is available on the design environments for large structures of the type to be used on the antenna. Of particular interest (and related to the fabrication process) are the environments induced in assembly, operation and refurbishment during the 30-year life. 4.2.4.2 Desired Output Structural design environments including acoustic, shock, acceleration, vibration, temperature, meteoroid, etc.; in addition the above are affected and influenced by the 30-year life operation. 4.2.5 Optimum Antenna Structures The cost of the MPTS is strongly dominated by the mass of the antenna support structure. Significant cost savings will be offered by an optimum structural arrangement for the environmental conditions and stiffness requirements. A study that takes into consideration the following factors should be performed: • Geometry • Design environments including effects of meteoroids • Life requirement (fracture, creep, fatigue creep buckling, etc.)
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