Thermal Protection System Sizing and Selection for RLVs Using the Sentry Code

*Technology research and development activities over the past two decades have resulted in several new material options for use as externally-bonded, passive thermal protection systems (TPS) on RLVs. These new materials each have unique thermal, structural and operating characteristics that make them well suited for protecting the underlying vehicle structure from extreme aeroheating environments associated with atmospheric flight. Depending on the material thicknesses used and the local stackup configurations, the overall weight (or weight per unit area) of these TPS solutions can vary considerably, thus optimal material selection and proper usage is critical. SpaceWorks Engineering’s Sentry software is a newly created engineering design tool for use in the conceptual and preliminary design of next-generation space transportation systems utilizing reusable, non-ablative thermal protection systems. Sentry performs a transient, 1-D thermal analysis of a vehicle’s TPS requirements at several hundred body locations throughout a given atmospheric flight trajectory and produces a weight-optimized TPS design that satisfies thermal, material and manufacturing constraints. This tool represents a unique capability update to the current suite of TPS selection and sizing tools available to engineers. The paper provides a summary of Sentry’s capabilities and reviews two case studies for which it has been successfully used.