Evaluation of a Novel Seal for Space Applications

To meet the requirements of future exploration missions to low Earth orbit, to the moon, and to Mars, a new docking system was developed by the National Aeronautics and Space Administration. A gas pressure seal is positioned at the interface between the twomating halves of the newdocking system. This interface sealmust operate across a wide range of temperatures while maintaining acceptable performance levels of both leak rate and the load required to compress the seal. A novel subscale test article was designed andmanufactured for evaluation purposes. The candidate seal was composed of a primary and a redundant elastomer seal retained by a metallic ring. The elastomer used to manufacture the seal was Esterline ELA-SA-401. The seal performance was characterized at environmental conditions across the representative system operational temperature range of 58 to 167 F.With a pressure differential of 14.7 psid applied, themass leak rate of air was quantified when the seal was fully compressed and at two levels of partial compression. The highest leak rate observed, 13:1 10 7 lbm=day-in:, was recorded when the seal was partially compressed at the highest test temperature. The force required to compress the seal increased with the test temperature and the largest force, 3700 lbf , was recorded at the highest test temperature. When compared with the system leak rate and compression force requirements, the seal met all of the requirements for all of the configurations tested.