Non-Weight-Based Cost Modeling

Abstract This paper discusses the advantages of non-weight-based cost models and uses launch vehicle rocket engine cost modeling as an example. Top level parametric cost models were generated for pump-fed liquid bipropellant booster and upper stage rocket engines in the 20 Kilopounds (Klbs) to 2,000 Klbs thrust class. The models cover production and full scale development costs and are based on thorough engineering analysis, not regression analysis, using data from historical rocket engines, potential engine derivatives, and proposed new engine concepts. The models depend on thermodynamic cycle, propellant type, thrust level, engine complexity, engine maturity, and other design parameters. The models are simple cost estimating relationships (CERs) with a transparent rationale and an accuracy of between 10 to 30%, depending on the engineering expertise used in the generation of the input variables. The format of the models and the rationale behind them are given in this paper. The cost models make use of a...