3.5 COST This subsection contains cost parametrics for mechanical systems and flight operations. Flight operations cost estimates are made for the entire SSPS including the recurring costs for suppport equipment. Mechanical System costs are estimated for the MPTS antenna and include the following cost elements: • Primary and secondary structure - Materials - Manufacturing • Materials transportation • Assembly 3.5.1 Task 1 - Preliminary Design Results The following summarizes the significant outputs of this initial activity: • The performance of the Interim Upper Stage (Transtage) is insufficient to transport assembly crews to the prime assembly site above the Van Allen belt • Assembly at low altitude results in a significant reduction in total structural system cost relative to assembly at the prime site • Kevlar/polyimide is the low cost material for assembly at 7000 n mi altitude • Aluminim structures would result in lowest cost structure for low altitude assembly • A 1.4 km diameter aluminum antenna is four times the cost of a 0.7 km diameter antenna. The top level alternate concepts assessed during Task 1 are summarized in Fig. 1-1. Four transportation modes, three structural materials, two structural arrangements and three antenna diameters were included in the preliminary matrix of options. The four transportation modes included: • Shuttle/Expendable Transtage (1980 IOC) • Shuttle/Reusable Transtage (1980 IOC) • Shuttle/Cryo Tug (1984 IOC) • Shuttle/Low Orbit Assembly (1980)
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