The focus of this study is to design a combustion system able to sustain hypersonic flight at Mach 8. A Dual-Mode Free-Jet combustion chamber design, first tested in 2010 by NASA, is being adapted to run on hydrogen fuel instead of ethylene while addressing the excessive thermal heat load. This study is part of the FAME (Flight at Mach Eight) project, with the primary objective to design and analyse the engine configuration for a hypersonic commercial aircraft. This CFD analysis and validation study, the first to replicate this combustion chamber design, provides detailed instructions on the combustion system design. The analysis from this study can be used for future research to successfully reach a sustainable design and operation of a Dual-Mode Free-Jet combustion chamber. The 53% size reduction in the combustion system represents significant progress which encourages future research regarding in the design of combustion systems for hypersonic propulsion systems. © 2019 by the author.