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:
The experiment will be conducted pre-, in-, and post-flight in order to develop a model for adaptation to and re-adaptation from the perceptual effects of microgravity. These experiments will be matched with experiments from non-astronaut control subjects on the ground.
There will be 1 pre-flight and 2 post-flight sessions using a virtual reality head-mounted display for 3 tests that evaluate (1) perceived tilt after traveling in a virtual environment, (2) perceived self-motion induced by visual optic flow, and (3) perceived distance of virtual targets. Tests will be conducted in both seated and supine positions.
There will be 2 in-flight sessions using the virtual reality head-mounted display for the same 3 tests conducted pre- and post-flight. Subjects will be tethered in place for stability.
This is an international experiment. NASA does not currently have an agreement with international space partners to archive their data in the LSDA.