The purpose of the Mental Representation of Spatial Cues During Space Flight (3D-Space) experiment was to investigate the effects of exposure to microgravity on the mental representation of spatial cues by astronauts during and after space flight. The absence of the gravitational frame of reference during space flight may be responsible for disturbances in the mental representation of spatial cues, such as the perception of horizontal and vertical lines, the perception of objects’ depth, and the perception of targets’ distance. This investigation included three perceptual/motor tasks, which were conducted pre-, in- and postflight. One task included writing words horizontally and vertically and drawing geometrical objects using a digitizing tablet. A second task involved adjusting the shape of a geometrical illusion or a three-dimensional object presented in a head-mounted virtual reality display. The third task included estimating the relative or absolute distances between objects and landmarks in three-dimensional images presented in the head-mounted display.
APPROACH:
Preflight baseline data collection (BDC) occurred at approximately launch minus (L-) 90, L-60, and L-30 days. One BDC session included performance of three perceptual/motor tasks lasting about 10 minutes each. One task included writing words horizontally and vertically and drawing geometrical objects using a digitizing tablet. A second task involved adjusting the shape of a geometrical illusion or a three-dimensional object presented in a head-mounted virtual reality display. The third task included estimating the relative or absolute distances between objects and landmarks in three-dimensional images presented in the head-mounted display. Postflight sessions were identical to those conducted preflight and were performed on return plus (R+) 0, R+1 or 2, R+4, and R+8 days.
Inflight sessions included the same tasks as the preflight and postflight BDC sessions along with set-up and stowage of associated equipment. Four sessions were planned, with the first session on flight day 10, the second and third session at mid-flight, and a final session within 1-2 weeks before landing. During the tasks subjects were free-floating to minimize orientation and cognitive reference cues.
RESULTS:
Over a three-year period, pre-, in-, and post- flight data were collected on eight International Space Station (ISS) crewmembers. The results include the following: 1) A 3D cube with smaller height than width is perceived as a perfect cube in-flight; 2) Hand drawn objects in-flight have greater height and smaller width than on the ground. Words written vertically in-flight are shorter (total vertical length of the word) than pre-flight, but longer immediately after return; and 3) Vertical distances are overestimated on Earth, but not late in-flight, and shorter distances ranging from 100-1000 feet, are underestimated.