Dedicated Launch of Small Satellites using Scramjets

Reduced scale and improved responsiveness will be the technical and economic drivers of future satellite systems. Based on decades of practical experience with rocket-only expendable launch vehicles, current technology is operated close to theoretical limits. Scramjets have an advantage over rocket propulsion in terms of a significantly higher specific impulse. Other benefits of airbreathing propulsion for access-to-space are increased launch flexibility and the possibility of reusable aircraft-like operations. This article describes the use of a three-stage rocket-scramjet-rocket system for transporting payloads of the order of 100 kg to a Sun Synchronous Orbit. The reusable second stage is based on a winged-cone vehicle and is powered by hydrogen fueled scramjets. Analysis of the complete three-stage system was performed based around a fully trimmed trajectory simulation of the second stage. The scramjet powered second stage accelerated from Mach 6.0 to Mach 9.3 with an average net specific impulse of 923 seconds. As a result, the overall system showed a payload mass fraction of 1.26% to Sun Synchronous orbit, which is significantly higher than expendable rocket based systems of this scale.