Spaceflight human optimization and performance: positioning astronauts in an operational framework to promote health, fitness, and mission readiness.

Optimizing astronaut mission readiness is a multidisciplinary endeavor that should integrate concepts from aerospace medicine, human performance, sports science, nutrition, and engineering. Situating astronauts within a theoretical framework similar to that of operational athletes, while addressing top human systems capability needs outlined for future missions, may be optimal for promoting sustained health and performance before, during, and after missions to low-Earth orbit, the lunar surface, and Mars. Mission readiness can be optimized by enhancing physiological and behavioral/psychological performance through data-driven and individualized exercise countermeasures, health and performance monitoring, precision nutrition, and rehabilitation strategies. Appropriate and stable space food systems that facilitate adequate provision of nutrients and fluids to prime astronauts for mission-critical tasks and operational demands are needed, though research is needed into potential nutritional considerations that might be useful for future missions. Behavioral readiness programs should emphasize stress inoculation, adaptive decision-making, communication, Earth-independent operation functionality, conflict resolution, leadership, and team-based problem-solving before flight to promote healthy team dynamics in-flight, along with proper society reintegration and uptake of family and occupational roles post-flight. Exercise remains an essential countermeasure during spaceflight, with an emphasis on maximizing fitness before launch to mitigate in-flight declines and on maintaining fitness levels and functionality during flight through high-intensity multimodal exercise. Following return to Earth, rehabilitative programs serve to restore cardiovascular, sensorimotor, and skeletal function, followed by enhancing skill-based performance components through a phase-based training program. Continuous monitoring systems that provide insight into health, performance, sleep, cognitive, nutritional, and recovery status should enable data-driven decision-making on physical readiness across all mission phases. By integrating insight from multiple disciplines, this unifying approach delivers a theoretical framework for sustaining astronaut health and performance during extended-duration missions.