Conclusions  Relying on earlier work regarding the vibration response of preloaded ball bearings, the investigation has  focused on the dynamic behavior of simplified bearing systems. In this conjunction, a dynamic model for  the axial degree of freedom has been developed in MATLAB®/Simulink®. As a key capacity beyond  predicting the load-deflection characteristics of bearing systems, it produces a numerical solution to the  dynamic problem. On top of this, a series of vibration tests has been performed on three sample bearing  cartridges. For validation of the computer-based model, special attention has been given to the postprocessing of the test results in the frequency domain as well as in the time domain.  The main findings of the investigation encompass the following aspects:  •In general, the behavior of hard preloaded bearings appears more linear and predictable with higher confidence than that of soft preloaded bearings. Snubber interactions in conjunction with gapping and hysteresis in soft preload systems are challenging details, which require further work. •The model-based prediction of load-deflection characteristics relies on an accurate knowledge of the most relevant bearing design parameters (like the free contact angle), which appears difficult to obtain for individual bearing samples without dedicated measurements (among others, because of production tolerances). •Performing static load tests to infer on the load-deflection characteristics of bearing systems may be helpful, however getting reliable results from static tests appears more difficult than expected (potential problems with test rig stiffness, sensor precision and parasitic effects). Acknowledgments  In the frame of the ongoing research project, the authors gratefully acknowledge the cooperation and  support by Grant Munro and Simon Lewis of the European Space Tribology Laboratory (ESTL, ESR  Technology). Furthermore, the authors would like to thank Ronan Le Letty and Lionel Gaillard (ESTEC  Mechanisms Section) for their encouragement and help, specifically regarding the in-house tests and  analysis work.   References  1. Munro, G., Checkley, M., Forshaw, T., Seiler, R. "Preloaded Bearing Characteristics under A xial Vibration." Proceedings of the 15th European Space Mechanisms and Tribology Symposium (ESMATS 2013) , September 2013. 2. European Cooperation of Space Standardization (ECSS) “Space Engineering: Mechanisms .” ECSS-E-ST-33-01C, Rev. 1, ESA, February 2017. 3.Videira, E., Lebreton, C., Gaillard, L., Lewis, S.D., “Guidelines for space mechanism ball bearing design assembly and preloading operations.” ADR, ESA and ESTL , September 2013. 4. Guay, P., Frikha, A. "Ball Bearing Stiffness. A New Approach Offering Analytical Expressions. " Proceedings of the 16th European Space Mechanisms and Tribology Symposium ( ESMATS 2015) , September 2015. 5. Harris, T. A. “Rolling Bearing Analysis.” Second edition, John Wiley and Sons, 1984. 6. Lewis, S. D. "Advanced bearing technology - Analysis and modelling report.” ESTL/TM/119, European Space Tribology Laboratory, March 1991. 7. Sarafin, T. P. “Spacecraft Structures and Mechanisms.” Springer, 1995. NASA/CP—2018-219887 96