Spacelab experiment. Astronaut Martin Fettman sitting in a rotating chair during an experiment conducted by astronaut Rhea Seddon (right). This experiment was one of many conducted during Shuttle Mission STS-58, when the second Spacelab Life Sciences module, SLS-2, was carried in the payload bay. This experiment was intended to test changes in reflexive eye movements in the microgravity conditions of orbit. All of the SLS-2 experiments were designed to study different aspects of the body's ability to adapt to weightless conditions for extended periods. Mission STS-58 flew on 18 October to 1 November 1993.