Skylab

This photograph is of Astronaut Kerwin wearing the Sleep Monitoring cap (Experiment M133) taken during the Skylab-2 mission. The Sleep Monitoring Experiment was a medical evaluation designed to objectively determine the amount and quality of crew members' inflight sleep. The experiment monitored and recorded electroencephalographic (EEG) and electrooculographic (EOG) activity during astronauts' sleep periods. One of the astronauts was selected for this experiment and wore a fitted cap during his sleep periods.