Abstract
Three tribological investigations related to vacuum or micro-gravity are presented in this paper. First, an adhesion phenomenon of clean metal surfaces in ultrahigh vacuum was microscopically analyzed using an AFM and TEM. It was shown that bonding stronger than the bulk strength of the softer metal arose at the real contact area due to diffusion of the mating metals. Second, a new solid lubrication technique called "tribo-coating" was applied to a ball bearing running in vacuum. The bearing showed longer life with low frictional torque compared with the existing Ag-lubricated bearing. Finally, performance of a gyroscope ball bearing in different gravity conditions was numerically investigated using a real-time dynamic simulation cord. It was demonstrated that the frictional torque and the retainer motion were more stable when the bearing operated in OG and in a vertical attitude in 1G compared with a horizontal attitude in 1G.
