Crew members from previous missions have routinely experienced a change in how they perceive objects and motions in space. Even something as simple as catching a ball involves complex interactions between the body's sensory and motor systems. Measurer marks off 2 spots, 3.5 meters apart. The same subject and tosser should be used for steps 3-10. Tosser, throws ball in a slow-underhand pitch to the subject who tries to catch the ball.
Subject returns the ball to tosser.
Repeat for a total of ten tosses to the subject. Recorder notes how many times the subject catches the ball out of ten tosses. Repeat the experiment with the subject lying face up on the floor, and the tosser on a stepladder, releasing the ball at a distance of 3.5 meters from the ground. Repeat the experiment with the subject in a chair at a distance of 3.5 meters from the tosser, the subject's back is facing the tosser and subject's head is hanging down the back of the chair. Recorder tallies the catches and misses in each category.