Liquid Space Lubricants Examined by Vibrational Microspectroscopy

Abstract

Considerable effort has been expended to develop liquid lubricants for satellites and space exploration vehicles. These lubricants must often perform under a range of harsh conditions such as vacuum, radiation, and temperature extremes while in orbit or in transit and in extremely dusty environments at destinations such as the moon and Mars. Historically, oil development was guided by terrestrial application, which did not provide sufficient space lubricants. Novel fluids such as perfluorinated polyethers provided some relief but are far from ideal. With each new fluid proposed to solve one problem, other problems have arisen. Much of the work performed at National Aeronautics and Space Adminstration's (NASA) Glenn Research Center, in elucidating mechanisms by which chemical degradation of space oils occur, has been done by infrared and Raman microspectroscopy, which this review details. Fundamental lubrication studies are presented as well as actual case studies, in which vibrational spectroscopy led to millions of dollars in savings and potentially prevented loss of mission.