Description: Availability of an alternate TPS material with reduced mass and expanded mission trade space to mission proposers, allowing enhanced scientific return from these missions, represents the anticipated value of this effort to NASA. Expected benefits include improved performance, greater reliability, lower costs, and enabling more missions. This technology maturation effort will enable capability to weave large scale, dual layer woven preforms of ~24" width by 2.1" thickness which is one of a kind as no such capability exists currently. Improved performance is achieved through 40% mass savings for a range of destinations and missions. Dual layer nature of the weave results in a more mass efficient and mission tailorable solution that accommodates broader mission design in achieving science goals. The 3D nature of the weave makes acreage material more robust than tape wrapped or chop molded Carbon Phenolic in all tests performed to date, hence resulting in grater reliability. Cost savings will be realized through reduced part count and complexity. The current loom scale up is constrained to 12" width due to technical constraints. An expansion to 24" width will reduce the overall part count in a future heatshields to ~25% of that when using 12" panels. The reduced part count reduces the integration complexity (tolerance stack-up). The reduced part count and complexity should lead to a reduced cost for implementation of panels from 24" width compared to panels from 12" width. By being more mass efficient, HEEET TPS opens up the mission trade space to trajectories (such as shallow high heat load entry flight path angles, or non-equatorial trajectories) that are not mass feasible with Carbon Phenolic TPS. These alternate trajectories will bring down entry g loads such that alternate science instrumentation become feasible (lower cost, increase capability, etc.) and lower mass may allow incorporation of additional instrumentation. HEEET is pushing the boundaries of the 3D woven technology by making use of the weaving and performance capability of the textile industry by expanding their application space to TPS. HEEET TPS is a dual layer, integrally woven preform that is further processed with a resin infusion step to achieve the desired ablative performance. To date, the weaving capability has been demonstrated for 1" thick x 6" wide preforms, with a dual layer in nature. The weaving manufacturer is currently under contract and upgrading weaving infrastructure (loom and hardware modifications) to scale-up weaving capability to 12" width x 2.1" thickness. The intent of this application is to expand the weaving capability to weave 24" width x 2.1" thick. The greater width of 24" is essential for risk reduction and offers many advantages to future missions looking at adopting HEEET including: increased design flexibility, reduced part count and brings the weakest link in the design, the seams between woven panels, into a less severe entry environment. The goal of HEEET is to develop a woven TPS technology to TRL 6 that will provide an ablative TPS solution for extreme entry missions. HEEET is a science enabler that will allow for very high return on the investment made by both NASA Space Technology Mission Directorate (STMD) for enabling technology development as well as Science Mission Directorate (SMD) on the science side under New Discovery and New Frontier programs. In addition, HEEET's unique capability has attracted the European Space Agency (ESA) mission proposers that want to partner with NASA under ESA�s M4 and M5 mission proposal calls.