A Comparative Analysis of Singe-State-To-Orbit Rocket and Air-Breathing Vehicles

This study compares and contrasts the performance of a variety of rocket and airbreathing, single-stage-to-orbit, reusable launch vehicles. Fuels considered include bi-propellant and tri-propellant combinations of hydrogen and hydrocarbon fuels. Astrox Corporation's HySIDE code was used to model the vehicles and predict their characteristics and performance. Vehicle empty mass, wetted area and growth rates were used as figures of merit to predict the total cost trends of a vehicle system as well as the system's practicality. Results were compared to those of two-stage-to-orbit reusable launch systems using similar modeling methods. The study found that single-stage-to-orbit vehicles using scramjet airbreathing propulsion outperform rocket systems. Findings also demonstrate the benefits of using hydrocarbon fuel in the early phases of ascent to reduce the size and mass of launch vehicles.