hinges running the 18 meter length of the waveguide as a means of rolling the array into as tight a bundle as possible, without affecting the dimensional characteristics of individual waveguides within the subarray (similar packaging approach as used to stow snow fence). After delivery of the subarrays to orbit, locking mechanism on the face opposite the hinge lines are utilized to securely deploy the subarray to within the required flatness. Figure 3.5-15 relates total waveguide system weight to packing density and number of Shuttle flights. The flight plans presented earlier in this section, assumed inflight fabrication of these units. A total of 25 flights was required to transport the 3. 95 Kg of 10 mil aluminum stock for inflight manufacture. The number of flights increases to 140 if the waveguides are fabricated on the ground and transported in the packaging arrangement shown in Fig. 3.5-14. The number of required flights remain constant up to a waveguide wall thickness of 50 mil. Above this material thickness, the Shuttle performance limitations become the driving factor for establishing quantity of flights. Transportation costs increase 20% from the baseline rate of 1301 $/kw to 1550 $/kw if space fabrication is not used for the waveguide. This 20% increase holds up to a waveguide wall thickness of 50 mil. At a thickness of 100 mil, the increase in cost is 50%. Figure 3.5-16 summarizes the cost delta’s as a function of waveguide wall thickness. 3.5.3 MPTS Structural Costs The cost elements for mechanical systems and flight operations have been broken down into the following subdivisions: • Primary and secondary structure - Materials - Manufacturing • Materials transportation • Assembly. Cost parametrics for the structure are in 1974 dollars and include the cost of materials and thermal coatings. The manufacturing processing costs for prelaunch forming of beam elements and application of thermal coatings are included. Cost relationships are in the form of $/Kg.
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