Evaluation of the Functional Capabilities of the Crew when Performing Extravehicular Activities after Long-Term Isolation in a Ground Based Model of a Space Station

During interplanetary expeditions, the crew must adapt not only to gravity transitions but also to long-term stay in a limited space of a space station. In such conditions, it develops a significant decrease in motor activity and the formation of a special stereotype of movements in these conditions. Within further planning of ground-based and real interplanetary missions, it is appropriate to assess the impact of these factors on the crew’s functional condition, including when modeling lunar gravity using suspension and virtual reality (VR) technologies. The purpose was to determine the functional capabilities of five members of the international crew of the 240-day SIRIUS-21 isolation experiment when performing an extravehicular activity (EVA) after 4 and 6 months of isolation in the hermetic facility. During EVA, the crew performed basic motor tasks using VR on an uneven surface: positional tests, voluntary and tandem walking, walking when avoiding and stepping over obstacles, and verticalization from lying and standing on one knee positions. The EVA scenario included tasks of controlling the rover with the arms deweighted, as well as movement in a VR environment on a sliding surface with the body deweighted on the moon. In this study, we presented results of qualitative and quantitative analysis of video recording data and qualitative analysis of the electromyographic activity of the muscles of the lower extremities. The results indicate a sufficient level of functional performance of SIRIUS-21 crew members, all the EVA tasks were completed by the crew in full, while no cases of significant loss of balance and signs of pronounced locomotor and vestibular disorders were registered. At the same time, this paper highlights some features of the crew’s EVA performance, the effects of sensorimotor training on some tasks with repeated EVA experience, the most common errors, and difficulties in performing the tasks of the EVA scenario.