Description: Based on the recent success of the Mars Exploration Program and the Mars Science Laboratory mission, NASA has a desire to expand on the technology developed under each effort in order to increase future mission capabilities, namely an increase in payload capacity for entry to Mars, Venus and other Outer-Planets. Such a goal requires an innovative solution to the vehicle's entry, decent and landing system (EDL). In order to address this goal,NASA has recently invested in the development of low ballistic coefficient aeroshell technology concepts which typically consist of a flexible 3D woven carbon cloth that can be stowed during flight and deployed to serve as a semi-rigid aeroshell on atmospheric entry. The ability of individual groups of fibers within yarn bundles to undulate in multiple orientations relative to the major axis of the yarn bundle results in full anisotropy for the 3D woven preforms. In addition to adding more complexity to the accompanying analytical models, the testing of such materials is also complicated as compared to isotropic and transversely orthotropic materials. Within the proposed Phase I effort, Materials Research & Design will develop test methods for the materials characterization of a hybrid, woven 3D fabric for use in a flexible TPS application. The program willinvolve analytical, fabrication and experimental tasks to achieve the overall program goal of maturing technologies for advanced EDL systems. A few select tests will be performed at Southern Research Institute with strain data being captured for use in the anisotropic compliance matrix calculations. Finite element simulations, using a homogeneous representation of the anisotropic material, will be used to simulate each test and aide in the design of test specimens sufficient to generate measurable strain levels while simultaneously allowing the anisotropic material to deform naturally.

Benefits: The successful completion of the Phase I program would directly benefit an existing, on-going NASA programs which incorporate flexible TPS designs: the Adaptable, Deployable Entry and Placement Technology (ADEPT) program. This program has made significant progress to advance the technology of deployable flexible aeroshells of 3D woven construction. However, there are still multiple risks associated with these designs. Although it is nearly impossible to address all of these risks, the development of sufficient test methods to calculate the material's compliances is an important step to reduce risk in the design.

Relative to commercial space transportation, the Space Act Agreement demonstrates NASA's financial and technical commitment to expanding access to space through a partnership with various organizations. Although these organizations, including Space Exploration Technologies, Orbital Technologies, Boeing and Sierra Nevada Corporation, have made great strides in advancing commercial space travel, their technology has thus far been applied only to low Earth orbit and travel to the International Space Station. However, this does not mean that such organizations could not benefit from low ballistic coefficient aeroshell technology. Based on the improved interlaminar properties and the ability to tailor the material design for a specific application, the increased use of 3D woven fabrics in ballistic protection, structural members, stiffeners and joints has benefited numerous other industries, including automotive, marine, construction and ballistic protection. As part of the commercialization strategy, MR&D will also perform a market research analysis on these industries since in order to identify additional areas within the commercial sector that would benefit from the development of credible test methods for 3D woven fabrics.