Skylab

This Skylab-2 onboard photograph shows astronaut Charles "Pete" Conrad exercising on a stationary bicycle (ergometer) used for monitoring the metabolism of the astronauts. The ergometer was used to conduct both Vectorcardiogram experiment (M093) and Metabolic Activity experiment (M171). Experiment M093 was a medical evaluation designed to monitor changes in astronauts' cardiovascular systems, while Experiment M171 was to measure astronauts' metabolic changes during long-duration space missions.