MEDES - VVIS
The system comprises a seat situated at the end of a bar that rotates. The subject sits at the end of the bar—moving forward into the direction of movement or backward from it-or lie on their back with their head " out " from the center of rotation.
Rotation of the seat is servo-controlled, with acceleration/deceleration up to 35deg/s/s. The distance between the head and the axis of rotation is either 50 cm (subject upright) or 60 cm (subject lying on his back). The seat rotates up to 45 rpm (subject upright) to achieve a centripetal acceleration equivalent to 1-g for up to eight minutes at a time. The head of the subject is restrained to the seat by means of a custom-made mask. The subject faces a head display for the presentation of moving stripes (optokinetic stimulation) or spots of light (saccades or smooth pursuit). When no visual stimulus is displayed the head display seals out any light from the spacecraft, so the subject must depend on the inner ear to sense any motion. Movements of both eyes can be monitored by means of two infrared video cameras. Images of both eyes are recorded on two VCRs installed on the centrifuge, together with parameters such as chair velocity, acceleration along three-axis at the head level, status of the visual stimuli, etc.
Last update: 23 January 2012