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Ambiguous Tilt and Translation Motion Cues After Space Flight (Zag)
03.22.12

Overview | Description | Applications | Operations | Results | Publications | Images

Experiment/Payload Overview

Information provided courtesy of the Erasmus Experiment Archive.
Brief Summary

Ambiguous Tilt and Translation Motion Cues After Space Flight (Zag) investigates the exposure to combined tilt and translation motion profiles for space explorers who have experienced microgravity.

Principal Investigator

  • Gilles Clement, Ph.D., Centre National de la Recherche Scientifique, Toulouse, , France

    • Co-Investigator(s)/Collaborator(s)

  • A. Rupert, M.D., Naval Aviation Medical Research Laboratory, Pensacola, FL, United States
  • Deborah Harm, Ph.D., Johnson Space Center, Houston, TX, United States
  • M. F. Reschke, , , , ,
  • P. Denise, , , , , France
  • Scott J. Wood, Ph.D., Universities Space Research Association, Houston, TX, United States

    • Payload Developer

    Naval Aviation Medical Research Laboratory, Pensacola, FL, United States
    Johnson Space Center, Houston, TX, United States
    Centre National de la Recherche Scientifique, Toulouse, , France

    Sponsoring Space Agency

    European Space Agency (ESA)

    Sponsoring Organization:

    Information Pending

    ISS Expedition Duration:

    October 2007 - September 2011



    Expeditions Assigned

    16, 17, 18, 19/20, 21/22, 23/24, 25/26, 27/28

    Previous ISS Missions

    Zag was first operated on ISS Expedition 16.

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    Experiment/Payload Description

    Research Summary

    • The balance system in the inner ear (otoliths) senses both head translation and head tilt relative to gravity. During space flight, head tilt is not sensed; the brain must therefore learn new ways of orienting oneself in weightlessness, which can then lead to disturbances in perceived motion and balance control upon return to Earth's gravity. The purpose of this research is to examine how the brain adapts to conflicting sensory conditions that may result in motion disturbances after space flight. Before and after space flight, subjects are exposed to a combination of body tilt and translation on a sled or a centrifuge. Changes in eye movements and awareness of position will serve to measure how the brain adapts to conflicting motion cues.


    • The Ambiguous Tilt and Translation Motion Cues After Space Flight (Zag) investigation will explore physiological mechanisms and operational implications of spatial disorientation and tilt-translation disturbances reported by crewmembers when making head movements during and following re-entry.


    • Zag will also evaluate a tactile prosthesis as a countermeasure for improving control of whole-body orientation during passive tilt and translation motion paradigms.


    Description

    The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during space flight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation and perceptual illusions following G-transitions. This study is designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances following short duration space flights. Specifically, this study addresses three questions:

    • What adaptive changes occur in eye movements and perception in response to different combinations of tilt and translation motion?

    • Do adaptive changes in tilt-translation responses impair ability to manually control vehicle orientation?

    • Can sensory substitution aids (e.g., tactile) mitigate risks associated with manual control of vehicle orientation?
    The first specific aim of this experiment will be to examine the effects of stimulus frequency on adaptive changes in eye movements and motion perception during combined tilt and translation motion profiles. Sinusoidal linear motion will be provided by a Variable Radius Centrifuge (VRC) in the roll plane and by a Tilt-Translation Sled (TTS) in the pitch plane. The VRC paradigm provides otolith and other graviceptor cues regarding tilt orientation without concordant canal cues, which are absent during constant velocity rotation. The TTS paradigm, on the other hand, provides canal cues regarding tilt orientation without concordant otolith cues by maintaining the resultant gravitoinertial vector aligned with the body longitudinal (Z) axis. The second specific aim will employ a closed-loop nulling task in which subjects will be tasked to use a joystick to null out tilt motion disturbances on these two devices. The third specific aim will be to evaluate how a tactile prosthesis can be used to improve control performance. The results of this study will contribute to refining the ability of the tactile prosthesis to improve spatial orientation and navigation and serve as a countermeasure for tilt-translation disturbances following space flight.

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    Applications

    Space Applications

    Information Pending

    Earth Applications

    Information Pending

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    Operations

    Operational Requirements

    Information Pending

    Operational Protocols

    ZAG consists of exposing seated upright subjects in darkness to combined tilt and translation motion during tilt and translation disturbances and to measure their eye movements, motion/orientation perception, and manual control performance during preflight and postflight sessions. During these sessions a Tilt-Translation System (TTS) and a Variable Radius Centrifuge (VRC) will be used. Eight subjects will participate in three preflight sessions (L-120, L-60 and L-30 days); the same subjects will participate in four postflight sessions (R+0, R+1, R+4 and R+8).

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    Results/More Information

    Information Pending

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    Related Web Sites
  • The information on this page is provided courtesy of the ESA Erasmus Experiment Archive.
  • Columbus Mission - European Experiment Programme

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    Publications

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    Ground Based Results Publications

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    ISS Patent Publications

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    Related Publications

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    Images

    imageTest subject in the Variable Radius Centrifuge which will be used during the Zag preflight and postflight sessions, image courtesy of ESA.


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    imageTest subject in the Variable Radius Centrifuge (VRC). Credit NASA


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    Information provided by the investigation team to the ISS Program Scientist's Office.
    If updates are needed to the summary please contact JSC-ISS-Program-Science-Group. For other general questions regarding space station research and technology, please feel free to call our help line at 281-244-6187 or e-mail at JSC-ISS-Payloads-Helpline.
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