596. Estimating Cost During Advanced Design by the Use of Weight Analysis

Paper

Abstract

Development cost and material requirements have commonly been based upon the predicted weight of aerospace vehicle components during the advance design phase. These analyses have proven in later reviews to reflect significant accuracy. This approach has been extended to employ a more intensive use of the advance design weight analysis in combination with previous engineering analyses. The approach was tested for its application to advance phase costing of vehicle subsystems and, further, the engineering, development, and qualification testing components of the total cost. The evaluation of several programs reflects a consistent analogy between the vehicle weights and component costs. Provided sufficient accuracy is obtained in the advanced weight analysis, the resulting cost analysis can exhibit a greater degree of confidence.
The related cost factors concerning the component material, reliability requirements, method by which the component is to be obtained, etc., must not be reduced in importance. The accuracy of the initial cost analysis is a function of adequate utilization of all available data of each cost factor. In this manner the disadvantage of performing cost analysis on a new type vehicle, as previously experienced with spacecraft systems, is reduced to an acceptable level.
The scope of this paper is to introduce the extended use of the advance design weight analysis data in the initial vehicle cost predictions. Reports from previous programs of similar nature (booster vehicles, surface-to-air missiles, short or extended duration spacecraft, etc.) are used to verily the usefulness of this approach. How well the cost factors of a vehicle subsystem repeat between programs can be simplified by further reducing the level of the subsystem groups considered during the analysis.
The advance design weight analysis may reveal very little indication of the engineering, development, and testing cost if no reference to a similar vehicle is available. This condition can be rectified by a correlation of the weight analysis with that of a non-similar vehicle for a more detailed component comparison. While the subsystems as a whole may be completely incompatible, a comparison of the components or subsystem groups will likely show a high degree of conformity. It is with this level of hardware that a large percentage of the component costs of the new design can be accurately determined.
The ratio of weight of a subsystem attributed to each material, operating function, and method of fabrication should serve as a bias in the comparison between vehicles. A weight breakdown by material is an accepted standard to the mechanics of component pricing. The function that the component is to perform, the expected operating life, and the operating environment provide excellent criteria for rating similar components for comparison of weight and cost.