Lessons Learned  The Nedox SF-2 low-friction coating caused significant issues. Some of the issues encountered include:  lost all part serialization, baked out to wrong temperature (per industry/vendor specifications), and rough  handling (deep marks visible in titanium). While process inspection and/or quality control points help prevent  issues, post-machining activities can fall through the cracks due to their perceived low technical or  programmatic risk. Therefore, it is important to consider a part’s complexity (e.g. lead-time, cost) when  deciding on the proper oversight at a vendor facility. The design team should carefully consider whether  each post-machining activity is required, especially when requiring a third-party vendor. If the activity is still  required, the design team should strive to minimize masking and carefully manage the activity.   To limit the tunnel vision syndrome, this author actively engaged a broad set of senior personnel for  constructive criticism of the design throughout the design cycle (not just at design reviews). While providing  the obvious benefit of pointing out design shortcoming(s) along with potential solutions(s), they can also  help provide cover from the continual battle of micromanagement by “others”. Ultimately, final design  decision should always remain with the mechanism team, but the team should make design decisions with  eyes open to the associated compromises. This was a large contributor to the team’s success. Conclusion  The mechanism has demonstrated by test the capability to survive the mechanical and thermal  environments specified. Based on both FEM and test validation, the mechanism thermoelastic distortion  has inherent hysteresis and uncertainty, but the characteristic over temperature is enveloped by a few  simple 1-D equations. While the commanded motion has been demonstrated by test to be repeatable to  better than the 6% requirement over the entire range of motion, the mechanism might not have a linear  relationship between step size and angular motion. To achieve the thermoelastic distortion stability and the  commanded motion performance required, understanding sub-micron motion is required, which drives the  test setup requirements. While having limited resources (personnel, schedule, money), two highperformance space mechanisms can be delivered in a short period (roughly two years).   Key Future Work  •After the mechanism life cycle test program is complete, the mechanism will be disassembled. Of particular interest, the gapping/sliding surfaces will be inspected for unacceptable damage or wear. •Commanded motion performance tests will measure isothermal mechanism motion for each flight AM, using an identical test setup discussed for thermoelastic distortion testing. Acknowledgements:  Mike Johnson, Don Sevilla, Kim Aaron, Gary Wang, Andy Kissil, and Kerry Klein for being a constant source  of independent and constructive feedback from the concept design through flight hardware testing. The  entire mechanism team: Brandon Metz (Electronics), ATA structural analysis support, Eddie Ketsiri  (Drawing), Robert Demerjian (Manufacturing), Don Lewis (Materials). Last but not least, PMIC staff for  working long shifts through the holidays! The research was carried out at the Jet Propulsion Laboratory,  California Institute of Technology, under a contract with the National Aeronautics and Space Administration  References  1. MIL-HDBK-5J-1. (2003). Metallic Materials and Elements for Aerospace Vehicle Structures. Department of Defense. 2. Touloukian, Y., Kirby, R., Taylor, R., & Desai, P. (1975). Thermal Expansion: Metallic Elements and Alloys (Volume 12).  New York: Purdue Research Foundation. 3. Walter D. Pilkey, D. F. (2008). Peterson's Stress Concentration Factors. John Wiley & Sons. 4.Witold M. Sokolowski, S. F. (1993). Dimensional Stability of High-Purity Invar 36. International Symposium on Optics, Imaging, and Instrumentation.  San Diego. NASA/CP—2018-219887 40