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The Effect of Long Duration Hypogravity on the Perception of Self-Motion (VECTION)
Principal Investigator
Species Studied
Scientific Name: Homo sapiens Species: Human


On ground, the perception of self-motion is a multi-sensory task predominantly determined by the vestibular and visual systems. The vestibular system transduces both external forces and gravity. However, in a microgravity environment the vestibular system is no longer affected by gravity, which may disrupt astronauts’ perception of distance, self-motion, and interpretation of tilt and translation. Given that astronauts are routinely required to estimate their motion in order to complete mission requirements, understanding how self-motion is estimated under microgravity conditions is key to mission safety.

The VECTION project will develop a model to examine how human visual self-motion perception is altered during long-duration microgravity conditions. Visual motion cues will be presented on a virtual reality head-mounted display to elicit a sense of self-motion. The subject’s ability to give spatial updates based on visual motion cues will be assessed by measuring how far the participant needs to virtually “travel” through the simulated environment to reach a visual target. Perceived tilt and translation will be evaluated by measuring perceived orientation following the simulation. After “traveling” through the simulated environment, subjects will indicate their perceived orientation relative to the recollection of the external environment. An additional test will use virtual reality to measure perception of distance and evaluate the influence of microgravity on perceived distance.

The objectives of this experiment are to:

  1. Assess the effectivity of visual cues for motion before, during, and after long-duration exposure to microgravity
    1. Assess the perceived travel distance evoked by visual motion alone under microgravity compared to the effect of comparable simulations on ground
    2. Assess whether distances in the visual scene in general are misperceived in microgravity
  2. Assess whether visual motion cues might be subject to ambiguity in terms of tilt and translation before, during, and after long duration exposure to microgravity
  3. Generate a model that examines how long-duration exposure to microgravity may affect the processing of optic information to evoke self-motion and how this processing changes upon return to ground conditions

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Environmental exposure
Motion perception
Perceptual distortion
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Body orientation
Distance, actual
Distance, perceived
Perception of tilt
Perception of translation
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Expedition 58 12/18/2018 03/14/2019 85 days
Expedition 59 03/14/2019 06/24/2019 102 days
Expedition 60 06/24/2019 10/03/2019 101 days
Expedition 61 10/03/2019 02/06/2020 126 days
Expedition 62 02/06/2020 04/17/2020 70 days
Expedition 63 04/17/2020 10/21/2020 187 days
Expedition 64 10/21/2020 04/16/2021 177 days
Expedition 65 04/16/2021 10/17/2021 184 days
Expedition 66 10/17/2021 03/30/2022 164 days

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Jessica Keune
Institutional Support
Canadian Space Agency (CSA)
Alternate Experiment Name
Proposal Date
Proposal Source