The objective of HEEET is to advance a dual-layer thermal protection system architecture by addressing the manufacturing capability, design tools, assembly, attachment, and seaming. The technology includes a dense outer mold-line layer constructed from high conductivity carbon fibers designed to handle peak heating and ablation, and a second inner layer consisting of blended carbon and phenolic fibers designed to have a lower thermal conductivity that will efficiently handle the integrated heating of entry. The technical approach allows the thicknesses of each layer to be optimized to meet the specific missions in a robust and mass-efficient manner. The project is working with industry manufactures to assure technology transfer and facilitate sustainable engineering implementation for future NASA missions. The project will demonstrate the capability through the design and build of assembly hardware and production of a 1-meter diameter, flight relevant engineering test unit to validate the quality of the manufacturing and assembly processes and mechanically tested to demonstrate structural capability for a mission-relevant testing.