Maximum prices anticipate a 20-25% inflationary raise during the 1974-1975 timespan for most of the materials listed in Fig. 3.5-17 except for the Kevlar maximum price which is a more expensive form of this particular material. Kevlar prices may drop in the near future as usage of this man-made fiber increases. Processing costs were based on a recent study for the VFAX airplane design in which an analysis considered metal and composite designs. These costs are based on the current $14-$15 per hour manufacturing rate. They reflect a 75-80% learning curve, with maximum cost taken at Ship No. 1 and minimum cost at Ship No. 150. It is understood that 150 ships may not be built, but that within each ship there exists sufficient repetitive structure such that mass production of identical items will tend to lower unit cost as more and more items are built. For further in-depth reference the reader is directed to Ref 17. 3.5.3.2 Transportation and Assembly Figure 3.5-18 summarizes the cost relationships used in comparing MPTS structural options. The cost of materials transportation assumes the Shuttle can deliver 29.4 x 103 Kg (65 K/lb) to 190 n mi at a cost of $10.5M per flight. In the four month period allocated to the assembly of the antenna, eight flights were needed for transportation of consumables and personnel (see Subsection 3.5.2). It is assumed that the type of material used in the construction of the antenna does not affect this requirement. The cost of equipments for support of assembly and the cost of SEPS transportation to geosynchronous was allocated in proportion to the baseline antenna weight to solar array weight ratio used in the traffic model assessment and was assumed independent of structural material. Figure 3.5-19 shows that aluminum is the low cost material for the antenna structure. The three graphite/composite options evaluated are: • Graphite/epoxy - 5 mil material • Graphite/epoxy - 2 mil material • Graphite/polyimide - 2 mil material. The increased cost of the graphite composite materials and prelaunch processing relative to aluminum is greater than the transportation cost savings achieved with the lighter material. These composite cost estimates are based on projected costs of graphite material in quantities of a few thousand pounds. Vendor contacts have indicated, however, that large quantity orders (millions of pounds) may significantly reduce these costs.
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