Task performance with touchscreen interfaces under conditions of head-down tilt bed rest

The application of touchscreen-based interfaces in space travel has become increasingly common. As space travel greatly depends on efficient human performance, understanding how conditions during space missions affect performance is crucial. Prior research has demonstrated the adverse effects of microgravity in various performance tasks. While these effects have been studied in tasks involving non-interactive objects or "conventional" input modalities, few studies have examined how these findings transfer to touchscreen-based interfaces. The present study investigated changes in performance with a touchscreen-based interface under head-down tilt bed rest conditions (HDT). 24 participants performed multidirectional tapping tasks in a 60-day HDT study (- 6 degrees head-down tilt position) at six subsequent points in time: 12 days prior to HDT, at 5, 21, and 56 days in HDT, and 4 and 90 days following HDT. Results show that the relationship between Movement Time and task difficulty expressed by Fitts' law remains stable in HDT conditions. Moreover, analyses revealed elevated Error Rate and Touch Duration during HDT compared to baseline. Improvements in Throughput and Movement Time can be most likely attributed to practice effects. Future research directions motivated by the study results are discussed.