Design and evaluation of aerospike nozzles for an upper stage application

Aerospike nozzles are often studied because of their intrinsic self-adaptation behavior to the atmospheric pressure. Another unique feature of aerospike nozzles is their flexible and effective integration with the underlying vehicle. This latter aspect, if fully exploited, could be of interest for both lower stages operating in the atmosphere and for upper stages operating in vacuum. In this paper, a numerical analysis is carried out of the possible advantages of using an aerospike engine for a typical upper stage configuration, discussing basic aspects of aerospike and internal expansion design, clustering and plug truncation length.