NASA's Space Launch System (SLS) will provide the capability to travel to deep space. The current state-of-the-art material for structures of this scale is an aluminum alloy that poses significant challenges to further reduce weight while maintaining requisite safety margins. Existing human space flight vehicles do not utilize composites for primary structures since critical technologies have not been validated at scale in a relevant environment. The purpose of this project is to design, build, and test composite structures on the same scale needed to validate manufacturability, structural margins, and thermal isolation improvements. The objective is to provide designers a validated alternative structural material candidate in future trade studies for SLS as well as other large booster and space science platform structures. The project is a cooperative effort between the STMD and HEOMD, involving multiple NASA Centers. The project will also leverage collaborations with DoD, industry and academia to provide the most innovative and affordable ideas.