Crystal Formation (IMAGE) NASA/Johnson Space Center Caption This is a crystal formation within a 50 millimeter loop, taken on Expedition 6. Crystal growth investigations have been occurring on the station since before humans lived there because of the unique environment microgravity provides. 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.