A Two Stage-to-Orbit High Staging Mach Number Design Concept

This paper presents a Mach 23 staged two stage-to-orbit launch vehicle candidate. Previously, two stage-to-orbit launch vehicles considered subsonic, supersonic and hypersonic staging options. Studies have shown that performance optimized two stage launch vehicles have first stage performance capabilities that vary widely depending on the propulsion and type of fuel used in the first and second stage. A Mach 23 performance capable first stage could fly around the world and return from the takeoff site using a boost-glide-skip trajectory profile. A Mach 23 staged first stage would be significantly less difficult to develop compared to a single stage-to-orbit launch vehicle. The usable propellant fraction for the Mach 23 rocket-based combined cycle engine powered first stage presented in this paper is 0.614 and the payload fraction is 0.033.

Previous work by the authors has shown that a Mach 23 staged vehicle is close to the performance optimum when the operational orbit of the payload is considered as the performance requirement for a two-stage-to-orbit vehicle. A Mach 23 first stage capable launch vehicle can operate from a single launch site without the need for down-range recovery sites and a means of returning to the launch site. During each flight the first stage returns directly to the take-off site on an unpowered boost-glide-skip trajectory.