Structural Efficiency of Integrated Composite Structures for Future Space Launch Vehicle Airframe Applications

This paper summarizes the objectives and status for the Future-responsive Access to Space Technologies (FAST) Airframe and Structural Health Monitoring (SHM) Ground Experiment (AFGE) program. The FAST AFGE program is an Air Force Research Laboratory (AFRL) project focused on demonstrating the integration of composite structures technologies for application on future space launch vehicle airframes. Technology advancement of integrated composite structures is being performed by development and testing of an integrated airframe ground test article to reduce risks for future responsive access to space. The FAST AFGE test article consists of a liner-less, load bearing, composite cryogenic propellant tank with an integral common bulkhead and integral skirts. The composite propellant tank serves as the airframe fuselage and is integrated with lifting surfaces, thrust structure, thermal protection, and structural health monitoring capability. The primary focus of this paper includes a mass properties assessment for the major composite structural components of the AFGE integrated test article, the common bulkhead tank and the wing box carry-through structure. Structural design details are summarized including predicted mass properties of the major structural components compared to measured weights. Test article weights are used to derive total airframe mass properties for a Reference Flight System (RFS) reusable booster as a measure of structural efficiency. A comparison of structural efficiency is made with goals and thresholds for the FAST AFGE program. The test plan for the FAST AFGE integrated test article is summarized including mass property measurements, cryogenic fill with pressurization cycling, and mechanical/thermal load tests to demonstrate reliability, reusability, and potential nonlinearity to reduce airframe risks for future space launch vehicles.