Astronaut Ricky Arnold, NASA (IMAGE) NASA/Johnson Space Center Caption NASA astronaut Ricky Arnold performs maintenance on the Advanced Colloids Experiment Module located inside the Light Microscopy Module. 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.