March 1, 1973 – Astronaut Pete Conrad tries the “Human Vestibular Function, Experiment M131” during Skylab mission training at the Johnson Space Center: “The reference sphere with a magnetic rod is used by the astronaut to indicate body orientation non-visually. The litter chair in which he is seated can be rotated by a motor at its base or, when not being rotated, can tilt forward, backward or to either side.” (NASA)