Development of a Bulk Metallic Glass Planetary Gearmotor for Unheated Actuation in Cryogenic Environments

Bulk metallic glasses (BMGs), a class of amorphous metal alloys, were selected for development of gears for unheated actuators that can be used in cryogenic environments such as Mars, the Moon, and outer planetary icy bodies (e.g., Enceladus and Europa). Specifically, an alloy of Cu43Zr43Al7Be7 was used to successfully develop a BMG planetary gearbox and prototype and flight gearmotors for operation at ≤-180 C. In additional to lessons learned from all phases of development, components and configurations, testing (including shock and vibration), and qualification for use in the Cold Operable Lunar Deployable (robotic) Arm (COLDArm) system are presented.