After completion of the qualification test, wear was visible on the rollers of the translator assembly and on  the mating surfaces. Figure 2 shows the condition of one qualification test roller. Some loose particulatedebris was also found, which was collected and analyzed [1-2]. The worn surfaces and wear debris  provide evidence that the wear process was primarily adhesive wear. In the net it appears that the steel has transferred to the mating Ti6Al4V surfaces. The loose wear debris included both the steel and titanium alloy materials. The severity of wear was not the same on all rollers.                          Figure 1. Translator Assembly [Ref. 1] Figure 2. Condition of Roller After  Completion of Qualification Test [Ref. 2] The NASA Engineering and Safety Center (NESC) conducted an assessment to better understand the  wear and provide recommendations that could reduce mission risk [3-4]. Experiments conducted by the  NESC demonstrated that misalignment of a roller axis relative to the direction of travel is a key parameter  influencing the propensity for wear. The NESC recommended two design changes for the rollers as follows. It was recommended that the roller material be changed from annealed 440F steel to 440C steel  hardened to 58-60 Rockwell C. It was also recommended to change the roller profile geometry to  eliminate the flat section superimposed in the center of the crown and to increase the crown radius. The  NESC also recommended optimizing the assembly procedure to minimize roller misalignment.  The NESC has now completed additional work, reported herein, with goal to reduce mission risk from  wear debris. There is little guidance in the open literature concerning detailed characterization of wear particles and transport of such particles. This is perhaps because for most applications small amounts of  wear debris are of no consequence. The manufacture of semiconductors in a vacuum environment is one situation with similarity to the NIRSpec device in that high cleanliness is desired and wear particles can  be of concern. For the manufacturing of semiconductors, proper bearing seals in combination with solid film lubrication has been proposed and studied to minimize adverse effects of wear debris [5]. The scope of the effort reported herein is evaluation of “alternative materials” for this mechanism. The words  “alternative materials” includes coatings and solid lubrication films even if applied to the baseline substrate materials. For purposes on this study, it was assumed that the flight unit configuration would  use a cover and baseplate made from anodized Ti6Al4V. Laboratory Test Apparatus Testing was done using the NASA Glenn Research Center Vacuum Roller Rig (VRR). Previous work has  shown that the VRR can effectively simulate the mechanism contact conditions and wear phenomena  [3,4]. The VRR data are also useful to supplement results of qualification tests. The rig allows for application and measurement of a load pressing the rollers together while having a purposely misaligned and adjustable shaft angle. The rig is depicted in schematic form in Figure 3. A drive motor provides  motion to the driving roller. A second drive motor provides some motive power to the output roller toovercome bearing and seal friction. The output shaft roller is driven through a torque-limiting permanent magnet clutch. The clutch torque and the output shaft motor speed settings resulted in a net torque of  1 Nm through the output shaft and rolling slip of less than 2 percent. This closely approximates the  mechanism rollers that are essentially free-rolling but with some support bearing and seal drag torque.  The normal load pressing the rollers together is provided by an air cylinder. The cylinder acts through a  pivot point to rotate the plate that mounts the driving shaft and drive motor in an arc motion. The pressure  88