Cost efficiency as design and selection criterion for future launch vehicles

Abstract

First, the actual change of paradigm for launch systems development is discussed: a future new launch vehicle program will require a clear economic justification, different from that in the past where military requirements, technology demonstration and national prestige were the prime drivers. For the approval of a new vehicle development funding, the following requirements probably need to be fulfilled: (1) The specific transportation cost must be lower (i.e. 50% or less) than those of existing systems, and (2) the development cost is to be minimized by modern cost engineering and management principles. These ground rules are valid both for new Expendable Launch Vehicles (ELVs) as well as for Reusable Launch Vehicles (RLVs). For Europe, the GTO mission for the launch of geosynchronous satellites is still the prime requirement for the next generation launch system after ARIANE 5. This more complex mission (compared to the previously assumed Low Earth Orbit (LEO) target) makes the definition of the most cost-efficient concept a challenge. Several technical options are feasible. One important factor is the payload capability to be specified: a larger payload (with dual launch capability) reduces the specific transportation cost but increases the vehicle size and the required development effort. These effects are shown in the paper, as well as the impact of the launch rate (annual number of launches) on the specific transportation cost. It is further shown which cost reductions could be expected in principle for future Geo Transfer Orbit (GTO) launch systems, depending on the vehicle concept, the payload capability and launch rate.