The design and operation of a vacuum tribometer, based on the four-ball configuration, is described. This tribometer evaluates the tribological characteristics of liquid lubricants for space applications. Operating conditions include: room temperature, loads to approximately 1000N, speeds to approximately 500 rpm, and pressures of approximately 10(exp -6)Pa. Tests can also be run at atmospheric pressure with air or nitrogen. Some typical test results are included.
Lubricants, tribometer, space
Helmick, L. S. (1994). A Vacuum Four-Ball Tribometer to Evaluate Liquid Lubricants for Space Applications. NASA Technical Memorandum (106264).