The cost-effectiveness of modular and single-purpose rocket boosters and worldwide trends

A comparative system analysis of modular and single-purpose rocket boosters is presented. Interesting relationships between evaluation criteria and system variables are pointed out, such as the one between specific impulse and payload, and the application of the system methodology to optimizing the relationship is discussed. The use of algorithms to minimize the number of combinations of payloads and vehicles, and for optimizing the systems, is considered. It is concluded that the modular concept provides, in a cost-effective manner, a long-range flexibility which the single-purpose vehicle does not, and that the modular concept has not been exploited to its full advantage.