subjected to random vibration and sine sweep testing prior to testing in TVAC. This non-accelerated testing  is expected to begin in late summer of 2018.  Preparations are underway to assemble the BOLT at the time of writing this paper.  Summary  Some obvious and some not so obvious conclusions can be taken away from the OCI-specific bearing  cartridge application design effort. Several key points are summarized as follows:  •Interference fits and their change over temperature have a larger impact on resulting (as installed) preload than outer ring clamping force. •Ball material CTE mismatch with respect to the rings affects preload change over temperature at least as much as sleeve material choice. •Sleeve fit dominates preload variation compared to housing fit within the temperature range. •Ball CTE dominates preload change at the hot extreme as the sleeve and housing fits loosen and no longer radially squeeze the outer rings. •Silicon nitride provides benefits such as increased lubricant life, lower weight, and higher stiffness with the detriment of a significantly different CTE and corresponding change of preload with temperature. •25-degree contact angle provides lower operating contact stress with minimal loss of launch load capability (compared to 15-degree contact angle). •Parametric exploration of the design space allows a better understanding of the effects and significance of each parameter. •For critical or ultra-precision applications, do not immediately assume that commercial off-the-shelf components are the ideal solution. Fully investigate the design space for available alternatives. While there may be more time and expense invested in the initial design activity, savings will be forthcoming once mechanism integration and test phases have begun. Acknowledgements  The authors would like to thank the production, verification and quality team at Barden, especially Douglas  Stange, for their dedication to producing world-class bearings for OCI and engineers at BEI Precision for  their expertise at measuring and evaluating precision spindle assemblies. We also acknowledge the OCI  team that supported the effort as we worked through the lessons learned, as described in this paper and  others. We finally acknowledge Nick Kwiatkowski and Tom Huber for their outstanding efforts during  assembly.  References  [1] NASA Goddard Space Flight Center (2017). PACE. Retrieved from https://pace.gsfc.nasa.gov/ [2] “Keeping the PACE”, The Critical Path , Volume 25, Number 3, NASA Goddard Space Flight Center. Retrieved from https://fpd.gsfc.nasa.gov/critical_path/critical_path_17winter.pdf [3] Tang, C., et al, “A Study on the Effects of Ball Defects on the Fatigue Life in Hybrid Ball Bearings”, Proceedings from the 42nd Aerospace Mechanisms Symposium, May 2014, Baltimore, MD. [4] Park, W., et al, “Rolling Contact Fatigue and Load Capacity Tests of M62 Bearing Steel”, Proceedings from the 32nd Aerospace Mechanisms Symposium, May 1998, Cocoa Beach, FL. [5] Leveille, A. and Ward, P., “Wear Potential due to Low EHD Films during Elevated Temperatures”, Proceedings from the 42nd Aerospace Mechanisms Symposium, May 2014, Baltimore, MD. [6] Smith, D., et al, “REX 20/Si3N4 Control Moment Gyroscope Bearing Development”, Proceedings from the 32nd Aerospace Mechanisms Symposium, May 1998, Cocoa Beach, FL. NASA/CP—2018-219887 112