Servicing of User Payload Equipment in the Space Station Pressurized Environment

One of the major contributions which the permanently manned Space Station will make to the user community is the ability to extend the useful life of hardware through various forms of servicing. Servicing support facilities will include both unpressurized and pressurized work areas. The unpressurized area will permit astronauts operating in an Extravehicular Activity (EVA) mode or aided by robotics to accomplish Orbital Replacement Unit (ORU) and instrument changeout, test and verification, assembly, refueling, and limited repair. The pressurized facilities will provide the capability for astronauts operating in an Intravehicular Activity (IVA) mode to service OBUs and instruments brought into a module through an airlock, and also service user payload equipment located within the pressurized modules.