Space Physiology and Technology: Musculoskeletal Adaptations, Countermeasures, and Opportunities for Wearable Systems

Space poses significant challenges for humans, leading to physiological adaptations in response to an environment vastly different from Earth. A comprehensive understanding of these physiological adaptations is needed to devise effective countermeasures to support human life in space. This narrative review first focuses on the impact of the environment in space on the musculoskeletal system. It highlights the complex interplay between bone and muscle adaptations and their implications on astronaut health. Despite advances in current countermeasures, such as resistive exercise and pharmacological interventions, they remain partially effective, bulky, and resource-intensive, posing challenges for future missions aboard compact spacecraft. This review proposes wearable sensing and robotic technology as a promising alternative to overcome these limitations. Wearable systems, such as sensor-integrated suits and (soft) exoskeletons, can provide real-time monitoring, dynamic loading, and exercise protocols tailored to individual needs. These systems are lightweight, modular, and capable of operating in confined environments, making them ideal for long-duration missions. In addition to space applications, wearable technologies hold significant promise for terrestrial uses, supporting rehabilitation and assistance for the ageing population, individuals with musculoskeletal disorders, and enhance physical performance in healthy users. By integrating advanced materials, sensors and actuators, and intelligent and energy-efficient control, these technologies can bridge gaps in current countermeasures while offering broader applications on Earth.