Artificial gravity: head movements during short-radius centrifugation

Labyrinthine lesions and motion sickness susceptibility

“…The stimulus alternately brings the vertical and horizontal canals into and out of the plane of rotation, causing subjects to feel tumbling or pitching, disorientation, and nausea, which can finally result in vomiting. The number of head movements that subjects make before overwhelming nausea has been widely used as an operational definition of motion sickness susceptibility (Lackner and Graybiel 1994;Clément et al 2001;Young et al 2001;Dai et al 2003). A motion sickness score can also be calculated to characterize the level of motion sickness (Miller and Graybiel 1969;Hecht et al 2001;Young et al 2001).…”

Physics of Artificial Gravity

“…Stone (1973) suggests that this be no higher than 25%. However, in the light of recent ground-based data showing a rapid adaptation to the vestibular conflict generated by Coriolis force (Young et al 2001), this limit seems overly conservative. Also, during an experiment performed on board Skylab, it was observed that head movements made during rotation after 6 days in microgravity failed to elicit motion sickness or desorientation (Graybiel et al 1977).…”

“…For example, Young et al (2001) have recently shown that subjects can quickly adapt to motion sickness induced by rotation of the head during centrifugation at 23 rpm. Higher rotation rates permit a shorter radius to obtain a specified gravity level.…”

“…Of course, such a short-radius device would need to spin much faster than the 6-rpm limit envisioned for a large continuous system, and would produce significant Coriolis forces and motion sickness stimuli with head movement, at least until adaptation occurs. However, recent work on adaptation shows the likelihood of successful adaptation by most subjects to head movements, even at high angular rates (Young et al 2001). The short-radius centrifuge becomes particularly attractive when its dimensions shrink to the point that intermittent centrifugation could be carried out within the confines of a spacecraft.…”

History of Artificial Gravity

“…Antonutto et al (1993) in Udine found that subjects who were pedaling on a bicycle-powered short-arm centrifuge were able to make head movements without acute motion sickness while rotating at 19-21 rpm. Young, Hecht, and colleagues used the 2-m radius centrifuge at MIT (see Figure 3-01) to show that most subjects could adapt both their eye movements and motion sickness symptoms by rotating at 23 rpm (Young et al 2001). Both the Udine and the MIT studies were conducted at rotation rate sufficient to produce 1 g of horizontal centrifugal force or a net GIF of 1.4 g. In the Udine centrifuge, the GIF was aligned with the subject's, head-to-foot (Gz) axis, whereas in the more provocative MIT studies, the subject remained horizontal.…”