Manually Operated Pitch-Yaw Joint for the ORU Transfer Device

The Orbital Replaceable Unit (ORU) Transfer Device is a compact and mobile space crane that astronauts will use during extravehicular activity (EVA) assembly and maintenance tasks on the International Space Station (ISS). The ORU Transfer Device, herein referred to as the OTD, utilizes an articulated telescoping boom attached to a stanchion and will typically be mounted and used on the Crew and Equipment Translation Aid (CETA) cart. During EVA assembly and maintenance missions the OTD will be used to transfer ORUs to and from the CETA cart, storage locations and planned worksites along the space station truss. A key design requirement of the OTD is that it can be manually operated by an unrestrained astronaut without using electrical power. The pitch-yaw joint assembly, a major feature in the OTD, utilizes a friction clutch package that serves as a dynamic and static braking system and allows the astronaut to easily and precisely position an ORU attached at the end of the OTD telescoping boom. This paper describes the mechanisms developed for the OTD self-locking articulation system and its performance during evaluation and acceptance testing.