MOP
Motion Perception: Vestibular adaptation to G-transitions.
What is the aim of the experiment?
The main scientific objective of this experiment is to gain insight into the process of how the bodys vestibular system adapts to the absence of gravity. In humans, the vestibular system together with visual information determines the bodys coordination, posture and balance and the perception of movement and orientation.
The adaptation in the vestibular system will be assessed by comparing the perception of motion against the real movement of the body. To this end, the astronaut will be asked to fill in a short questionnaire every day during the spaceflight, wherein he reports his motion sensation as a result of head movements around the three principal axes. Head movements are important in the experiment as the inner ear is the location of the sensory organs of the vestibular system.
The astronaut will also be questioned on whether he experiences any discomfort regarding space adaptation syndrome, commonly known as space sickness, caused by their daily activities. A second objective of the Motion Perception experiment is to correlate an astronauts susceptibility to space sickness with a susceptibility to sickness induced by centrifugation. Sickness induced by centrifugation is a condition with similarities to space sickness. A pre-flight ground experiment will be performed wherein the astronauts susceptibility to sickness induced by centrifugation is assessed by exposing him to hypergravity (H3g) in a centrifuge.
Why do it in space?
In the 40 years of human space flight, many astronauts have reported motion sickness of varying severity and it has been a matter of study since the Apollo missions. The human vestibular system contains sensing elements called otoliths. Investigators have shown that a weightless environment provides a different stimulus to the otoliths of the inner ear, and therefore the signals from the otoliths no longer correspond with the visual and other sensory signals sent to the brain.
The weightlessness of space offers a unique environment to study the various components of spatial orientation, which are intrinsically linked to
gravity. It is the only environment in which the effect of gravity can be reduced to a minimum for sufficiently long periods in order to obtain conclusive data and results for this experiment. It provides the ability to manipulate spatial orientation and follow its adaptation during the early and late phases of flight and re-entry. Such experiments, which are of basic interest for understanding the organization and the neural basis for spatial orientation, cannot be done without using weightlessness.
What is it good for?
Besides the benefits this research could have in developing countermeasures to space sickness experienced by astronauts during the early phases of space flight, this type of research could have positive implications for research on Earth. These include studies on the balance system carried out to help people with equilibrium disorders, motor function development in children and the development of new methods for evaluating a patient's ability to use visual cues for maintaining balance and orientation.
Team Members:
J.E Bos, S. Nooij, W. Bles, E. Groen
TNO Human Factors
PO Box 23
3769 ZG Soesterberg
The Netherlands
Tel.: +31 346 356 371
Fax: +31 346 353 977
email: bos@tm.tno.nl
W. Ockels
University of Delft
Delft
The Netherlands
More Information:
A Fact Sheet of the MOP experiment is available for download as pdf-file in English and in Dutch.
Watch a presentation of the MOP experiment in streaming Internet video (in English) made during the weekly Delta mission video debriefing of 16 January 2004.
A summary description of the MOP experiment in Dutch is available at the ESA Dutch Internet Portal.
A detailed scientific description of the MOP experiment in English is available at the Delta mission Internet site of the Dutch Experiment Support Centre (DESC).