Reliability and cost considerations in launch vehicles

The inherent reliability of a space launch system, or lack thereof, is pointed out to often be a more significant determinant of access to orbit than the nominal cost. System improvements that enhance inherent reliability may accordingly represent the most economical approach to follow. At some point, the limitations of launch technologies currently in use must be acknowledged and novel methods developed. The dearth of systematic research efforts toward superior technology in launcher propulsion over the last 20 years is identified as a major limitation in the search for near-term options.