Comparative System Analysis of Reusable Rocket and Air-Breathing Launch Vehicles

Abstract

A conceptual system design study was performed to assess and compare the parameters of single- and two-stage reusable air-breathing and rocket launch vehicles to identify configurations which improve space access and merit further developmental emphasis. Investigated air-breathing configurations included both two-dimensional and inward-turning inlet geometries and horizontal and vertical takeoff modes utilizing rocket or turbine engines. The baseline payload requirement was 20,000 lb to low-Earth orbit. The vehicles were evaluated utilizing several figures of merit including empty weight, wetted area, and maintenance hours. A further weight growth assessment ascertained the growth factor which characterizes each system's design risk and growth response to technological uncertainty. An additional trade study investigated payloads up to 70,000 lb. The two-stage rocket results showed strong performance in applied metrics. Horizontal takeoff single- and two-stage air-breathers trailed far behind, while the vertical takeoff air-breathers were very competitive and merit further attention.