Evaluation Tests of Industrial Vacuum Bearings for Space Use

The tribological performance of industrial vacuum bearings for space use was experimentally evaluated. The bearings selected for investigation were an 8 mm bore deep-groove ball bearing lubricated with a sputtered MoS2 film and one lubricated with an ion-plated Ag film, commercially available from three Japanese bearing manufacturers. Based on survey results of tribological requirements for existing satellite mechanisms, four types of bearing tests were defined and conducted: a vacuum test at room temperature, an atmosphere resistance test, a thermal vacuum test, and a vibration test. In addition to these tests, the variation in the tribological performance of the industrial bearings was also investigated. The results of more than 80 tests demonstrated that the industrial vacuum bearings had sufficient lubrication lives with low frictional torque and the data were reasonably repeatable, indicating a potential for space use.