Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Carl R. Hartsfield, PhD.


The Air Force Institute of Technology (AFIT), working to meet requirements set by the Air Force Research Laboratory's Next Generation Engine (NGE) initiative, is developing upper stage rocket models. The current path of investigation focuses on combining a dual expander cycle with an aerospike nozzle, or the Dual Expander Aerospike Nozzle (DEAN) using methane fuel. The design process will rely heavily on AFIT's previous work, which focused on the development of tools for and the optimization of a hydrogen/oxygen DEAN engine. The work outlined in this paper expands the existing research by substituting methane for hydrogen. The targets derived from the NGE program include a vacuum specific impulse of 383 seconds, 25,000 lbf of thrust, and a thrust to weight ratio of 108. NASA's Numerical Propulsion System Simulation was used in conjunction with Phoenix Integration's ModelCenter to optimize over several parameters to include O/F ratio, thrust, and engine geometry. After thousands of iterations over the design space, the selected MDEAN engine concept has 349 s of Isp and a thrust to weight ratio of 120. The MDEAN was compared to liquid hydrogen technology, existing methane technology, and the NGE goals.

AFIT Designator


DTIC Accession Number