High reliability and durability are required from the aerospace articles. Therefore, the calculations of these articles and their components (mechanisms, units, parts, etc.) must be of high confidence with a view to ensuring which the actual serviceability criteria must be used in the calculations. The object of research in this study is planetary roller-screw gears used in the linear drives of articles. The main criterion of planetary roller-screw gears serviceability is the fatigue flaking, and the durability calculation shall be performed by dynamic load-lifting capacity. Such calculation does not allow obtaining answers to a whole host of issues. It was proved in the study that the actual criterion of planetary roller-screw gears serviceability is wear-resistance, and the calculation basis is given with account of such criterion.