Fig. 7. Production cost estimates for satellite hardware in millions of 1979 dollars. tend to give similar results. One suspects that learning curves in the 70% range, frequently attributed to high-production electronics, are more properly production rate factors. Limits. Unfettered use of factors will occasionally predict costs below materials and energy costs. This is particularly true if exotic materials or very high production rates are involved. Accordingly, the cost analyst must apply a “reasonableness” test to cost estimates to ensure that a realistic value-added factor on basic materials and energy cost is preserved. A minimum value-added factor is roughly 2. Very large industries such as the U.S. auto industry achieve about this performance. SPS cost analyses applied production rate factors to hardware elements with annual production rates greater than 100 units. The implied level of automation was thus varied with production rate. Numbers of units per SPS range from one, e.g., the slip ring, to millions, e.g., about 50 million 1-m2 solar array panels. Examples. Over half of the total reference SPS hardware cost is in three items — the solar array, the transmitter Klystrons, and structure and power conductor elements, as shown in Fig. 7. The reference system solar array costs assumed improvement and automation of known technology, i.e., growing and sawing of crystals. The array production plant includes fourteen process steps and tens of thousands of individual machines. The estimated floor area was 250,000 m2, larger than the Boeing 747 aircraft plant, and the
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