A Critical Parameter Optimization of Launch Vehicle Costs

Beginning in 2002, as part of the University of Maryland (UMd) Space Vehicle
Technology Institute (SVTI) under the NASA Constellation University Institutes Project
(CUIP), the UMd Space Systems Lab began a parametric analysis aimed at minimizing costs
of payload to low earth orbit (LEO). By identifying a range of market sizes (total program
payload to LEO), the effects of manipulating a number of critical parameters involving
vehicle configurations on payload costs were examined. Vehicle configurations encompass
single stage and multistage vehicles with combinations of airbreathing and/or rocket
propulsion systems. Launch systems could be expendable or reusable on a stage-by-stage
basis. Staging velocity is optimized for minimum cost at each design point. The costing
model includes the effects of learning on production and operations, discount factors for
multiyear investments, and the use of “refurbishment fraction” (fraction of initial
procurement costs required for reusable vehicle refurbishment between flights) for
estimating maintenance and turn-around costs. Overall vehicle recurring and nonrecurring
costs are estimated based on sets of inert-mass cost estimating relations drawn from
published sources