Robots in Space Suits

• The lack of long endurance lubricants in vacuum could be worked around by robots wearing space suits. Perhaps 0.3 psi would do for robots. At least a gas tight covering of knee of elbow joints could be done with a bellows that has a flanges pressed to points above and below the joint by a threaded ring. Electrical power wire, control wire, and thermal management fluid hoses could run in a bundle outside of the bellows and have connectors for wires and hoses that would run around the bellows to the pressurized space around the joint . That way the wires and hoses could be disconnected, the bellows unfastened, and the joint unpinned for maintenance.
• The astute reader will realize that this sort of joint covering will not work with rotary bearings of wheels rolling over the ground. So robots could walk and wheeled vehicles could have magnetic bearings. Such vehicles would not be suitable for bouncing over rough terrain, but might give high speed performance over smooth Roads. Wheeled vehicles might work with ordinary greased bearings and frequent lube jobs, or the lubricant rquirement might be solved by special grease and thermal management.
• A completely enclosed set of bearings and directional antenna could constantly communicate with a ground station from a rotating space station. A few layers of stuff transparent to the frequency used sandwhiched with three inch layers of vacuum could protect the gas retaining envelope from micrometeoroids.
• An arm of gas enveloped joints could point a telescope in arbitrary directions. Panning through 360 degree sweep would cause the image to roll 360 degrees unless there were a rotary bearing for roll control at the telescope end of the arm. A gas tight envelope for a roll control bearing could be maintained if part of the envelope were optical quality glass through which the telescope could see its target.