Issues Faced by Astronauts in the Field: The Mitigation of the Disruption of Circadian Rhythms

Circadian rhythm disruption is one of the greatest physiological challenges for many astronauts in space. This is because the microgravity and irregular light-dark cycles of space interfere with the body’s natural 24-hour clock. These rhythms govern important biological processes and are highly sensitive to environmental cues including light exposure, as well as activity patterns of the astronaut. As a result, the rhythms are very vulnerable in spaceflight conditions in which some of these factors are unpredictable. NASA currently relies on strategies like structured sleep schedules, controlled lighting systems, and educational programs to reduce circadian misalignment, but these countermeasures often lack flexibility and show variable effectiveness across individuals. This study investigates alternative and complementary solutions. In particular, we propose the targeted use of pharmaceutical chronobiotics and melatonin therapy as tools to reinforce circadian stability during extended missions. By evaluating the effectiveness, safety, and adaptability of these pharmacological interventions alongside existing approaches, this research seeks to identify optimized strategies for maintaining astronaut performance, health, and physiological stability in operational space environments.