A Case Study in NASA-DoD - The Black Vault

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Cost-estimating equations for spacecraft subsystems are typically
of the type
b
Y aX or Y a + bXC
where Y = cost, and
X f weight or other subsystem characteristic.
In the SAMSO model, for example, the cost of the attitude control
system is given by
ACS cost in thousands of 1974 $ f 14.72 (ACS dry weight) 9 0
In developing a model for this study the b-value, 0.90, was used with
an a-value based on AEM. That procedure gave the following equations
(all these costs are in thousands of 1976 dollars):
Structure, thermal control, interstage = 4.8 (weight) 7 4
.84
Electrical power system = 5.65 (weight)
.9
Attitude control system = 14.7 (weight)
.9
Communications and data handling = 25.4 (weight)'
In addition, the costs of system test and integration, program
management, quality assurance, reliability, etc., must be included,
and they add about another 50 percent to the total. On top of that
are the costs of special components, such as tape recorders, hydrazine
tanks, and solar panels not included in the basic configuration.
Component costs, even those of existing, flight-proven components,
vary considerably and add another measure of uncertainty to the total.
Vendor quotes, for example, can vary by more than an order of magnitude.
As shown below, the range of bids for a PCM encoder was from $21,400
to $611,000; in that same case the second-lowest bid was $41,200. Also,
It may be noted that the ACS estimating equation is essentially
the same as the one cited above for the SAMSO model. Apparently, inflation
effects have been offset by factors such as a low-cost design
approach and the cost-quantity effect.