Description: Key Technical Challenges: Designing a very high reduction ratio pericyclic gearbox that fits into a compact space, is low weight, efficient, and reliable over a long service life for Martian rover wheel actuators.\nApproach/Research Plan: Conduct Lliterature review on current and previous rover wheel actuator designs; Adapt and expand design approach used at GRC for aeronautic pericyclic research; Develop remaining components for gearbox such as bearings and mounting structures; and, test gearbox by checking gear tooth contact patterns, applying torque statically.\nDifferent/Complementary: Current efforts in academia are focusing on the application of the pericyclic gearbox in rotorcraft applications where the reduction ratio ranges from 20:1 to 40:1, input speeds are in the thousands of RPM, and output torque is fairly high. The application desired for this project would examine much higher reduction ratios in the 500:1 to 2000:1 range, input speeds would be in the mid thousands of RPM. \nNext Step: At the completion of this project, two different paths would be desirable: further maturation of the gearbox for the intended rover specific application; and, use this project as a capability demonstrator.

Benefits: Goal: To study, design, fabricate, and analyze a single stage pericyclic gearbox that matches or exceeds the performance of a multistage gearbox for rover wheel applications.\nCapability Need/Knowledge Gap: The pericyclic gearbox has been examined most notably in rotorcraft design spaces, but studies have not been performed on pushing the limits of its reduction ratio capabilities to extreme values. It is not clear what designs with very high reduction ratios (>500:1) are yet achievable.\nState-of-the-Art/Knowledge: Recent advancements in pericyclic research in academia have greatly developed understanding of the pericyclic gearbox's capabilities and tradeoffs. Additional advancements by gear manufacturers have also made precision machining of internal bevel gears, which are utilized in pericyclic gearboxes, a reality.