313   Figure 6  Typical seal-shaft observations for tests run with either JSC-1A or LHT-2M. 

Table 2 shows results of Bal-Seal tests through 10,0 00 cycles. In general, seal weight loss was greater  for increasingly larger seal diameters due to a larger contact area and increased surface speed due to increased circumference. For example, for dry- room tests run without simulant, the average seal weight loss ranged from 0.11 to 0.33% for the 9.5-mm (0.375-i n) diameter seals, from 0.07% to 0.66% for the 19mm (0.75 in) diameter seals and from 2.63 to 3.0% for the 38-mm (1.5 in) diameter seals. Post-test  roughness profiles for dry-room test shafts run without simulant (Tests A22, A23, B7, B20, C17, C18) were inconclusive ranging from -7.34% (smoother su rface) to +2.72% (rougher surface). In comparison,  these same tests run with JSC-1A (Tests A12, B 10, C6, A17) showed a more definitive roughness  change of +15% (rougher surface) on average. Preliminary tests in vacuum show minimal seal weight loss through 10,000 cycles. In fact seal weight loss was identical at -0.11% for the 9.5-mm (0.375-in) diameter seal tested without and with JSC-1A (Tests A13 and A15, respectively). Seal weight loss was doubled at -0.22% for the same sized seal tested wi th LHT-2M (Test A16). Although the vacuum test  results are encouraging, repeat tests are necessary to validate these results. Un fortunately, a malfunction  in the vacuum motor occurred after these 4 tests. Thus further testing was postponed. Post-test surface roughness profiles for the vacuum tested seals were again inconclusive with results ranging from -13.87%  (smoother surface) to +6.90% (rougher surface). Pre liminary tests of Bal-Seals against stainless steel  shafts show seal weight losses comparable to the anodized aluminum shafts. However, the large change in surface roughness for shaft S-10 does not appear to be consistent with the -0.11% seal weight loss of  Seal ID A18. In fact, this inconsistency between seal weight loss and change in shaft surface roughness is apparent for a large portion of the test results. Furt her analysis in data and procedures is necessary to  reconcile these differences in surface roughness wi th seal weight loss. Supplementary testing was  performed to determine cycles versus wear for three seal sizes. Results are shown in Figure 7. As  expected, the larger contact surface area of the 38 -mm (1.5 in) seals incurred more wear through 10,000  cycles than the 19-mm (0.75 in) or 9.5-mm (0.375-in) seals. Further long-term te sting is necessary to  determine if the seal wear rate remains constant, in creases, or possibly stabilizes to some final seal  weight loss. Note that these tests were run at constant speed and that future tests may involve start-stop cycles, ramp-up and ramp-down in s peed, etc. Finally, infrared microscopy has confirmed the presence of  Teflon being transferred to the anodized aluminum shaft surface. The presence of Teflon on the rotating surface provides additional lubrication between the s haft and seal which could potentially increasing sealshaft life. Further tests are needed to assess the perf ormance of this lubricating layer through extended  operations.   a. Downstream side.Shaft-seal interface JSC-1A Simulant b. Seal cartridge holder. Upstream side.Seal Teflon NASA/CP-2010-216272