PBRE Test (IMAGE) NASA/Johnson Space Center Caption One of the two PBRE test beds is shown. One column will use randomly packed glass beads (shown), while the other will use randomly packed Teflon beads. Credit NASA Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.