CMC Control Surface Designs

As space exploration and hypersonic cruise technologies develop, the focus has shifted towards the development of lightweight, fully reusable and lower cost vehicles. The current state-of-the-art (SOA) is taking an incremental improvement step over the Space Shuttle TPS approach. All-ceramic matrix composite (CMC) body flaps developed for the X-38 vehicle were shown to offer considerable mass savings as well as increased durability and impact resistance. The next step in advancing the state of the art is to increase the confidence in the design and manufacturing quality of a full CMC control surface for hypersonic vehicles. Within this effort, Materials Research & Design (MR & D) is proposing a trade study which will investigate various control surface manufacturing and material options for the ruddervator design of X-37B Orbital Test Vehicle. For the proposed Phase I program, MR & D has chosen an integrally fabricated all-CMC control surface, a mechanically fastened-individually fabricated fully-CMC control surface, and a CMC sandwich structure control surface to be the three candidate design structures in a trade study. Potential material candidates include, but may not be limited to, CVI C/SiC, C-C with 1-2 SiC cycles for oxidation protection, S200 Nicalon/SiNC from ATK COIC, and SiC/SiC.