Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Milton E. Franke, PhD


The Department of Defense (DoD) has identified operationally responsive, low-cost access to space as vital to maintaining U.S. military supremacy. Reusable Launch Vehicles (RLVs) will allow the U.S. to keep a technological advantage over our adversaries, and advances in airbreathing propulsion technology have made it feasible for use in space launch vehicles. This study considers two-stage-to-orbit (TSTO) RLV configurations, each using combinations of propulsion including pure rocket, pure turbine, rocket-based-combined-cycle (RBCC), and turbine-based-combined-cycle (TBCC) for the both stages. This study explores the advantages of airbreathing propulsion in those key areas when compared to a baseline configuration, using vehicle empty mass and vehicle wetted area as the primary figures of merit. Results show that a vehicle using airbreathing propulsion on the orbiter stage has a lower vehicle empty mass and wetted area than a pure rocket, and allows the RLV to gain the advantages of using airbreathing propulsion. The requirements used for this comparison are: 1) a payload module requirement of 20,000 pounds; 2) a 100x100 nautical mile, 28.5 lat. Easterly orbit and return; 3) use of hydrocarbon fuels (RP-1 and/or JP-7) and liquid hydrogen (LH2); and 4) use of liquid oxygen and/or air as oxidizers. ASTROX Corporation's Hypersonic System Integrated Design Environment (HySIDE) code is used as the design tool throughout the study.

AFIT Designator


DTIC Accession Number