Abstract
Upon landing after long-duration spaceflight, astronauts often experience motion sickness and impaired performance in mission-critical tasks such as egress, navigating obstacles, jumping, and recovering from falls. These changes are mainly attributable to central adaptations in their vestibular system. Current inflight countermeasures, which primarily focus on strength and endurance, are insufficient for preparing astronauts for postflight recovery. New countermeasures must be designed and tested to enable crewmembers to function without the extensive post-mission recovery support after landing on the Moon or Mars. Individuals with bilateral vestibulopathy are immune to motion sickness and might be better prepared for landing after spaceflight. They have adapted strategies for maintaining balance and orientation without relying on vestibular inputs, potentially making them more stable and less prone to disorientation in microgravity or rotating environments. Their unique adaptations may allow them to perform many mobility tasks more effectively during critical mission phases, such as vehicle egress, when other crew members might be more affected by vestibular issues. While they may not perform all tasks, these parastronauts can excel in specific roles that leverage their unique abilities, contributing to the mission's success in specialized capacities. We propose using lunar gravity achieved during parabolic flight and prolonged centrifugation as models to study how functional task performance might be less impaired in parastronauts with bilateral vestibulopathy compared to healthy individuals when landing on the Moon after extended exposure to microgravity.