Star Wars may have you believing that the greatest challenges of space travel are asteroids, a lack of resources such as water or fuel, or even the threat of hostile alien life. But in reality, scientists have discovered that the biggest obstacle to current space exploration is dust. Research on the effects of spaceflight and terrestrial analogs of spaceflight has revealed that there is an increased risk of bone and muscle loss, cardiovascular degradation, heightened oxidative stress, and more. In summary, evidence from both spaceflight and its analogs suggest that the biomedical risk is a high probability and high consequence risk for exploration. Although research on the long-term health risks of cancer has been delayed, research on the effects of radiation on the cardiovascular system and central nervous system during flight in the context of the space exposome is considered to be of utmost priority and is the focus of current research. Due to the lack of human data on exposure to heavy ions on Earth and the difficulties in obtaining reliable data on the health effects of space radiation from flight studies, NASA's Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory is conducting research.
The main threats to human health and performance associated with space travel are radiation, altered gravity fields, hostile and closed environments, distance from Earth, and isolation and confinement. The main outcomes of this risk include a decline in cognitive function, operational performance, psychological and behavioral states, and the development of psychiatric disorders. To ensure successful missions, the health and performance risks associated with the unique hazards of spaceflight must be properly managed. Astronauts' nutritional status changes after a long-term space mission aboard the International Space Station. As their bodies adapt to their new environment, some conditions improve while others may persist or worsen with time spent in space.
As long-term manned missions to the Moon and even Mars become a reality, scientists are beginning to address the problems posed by surgery in space. In January 2004, NASA's Opportunity rover landed on Mars for a 90-day mission (on Martian days) to search for evidence of water on the Red Planet. The unique environment of space means that sick astronauts are more likely to die from injuries and minor infections than they would be on Earth. While NASA is conducting initial evaluations of diet quality and health, much work remains to be done to document the full potential of nutrition to mitigate bone loss and other pathological processes in space travelers. NASA's Human Research Program (HRP) is dedicated to developing and providing the knowledge base, technologies, and countermeasure strategies that will enable safe and successful manned space flights. Using analog missions and extensive social science research, space agencies around the world have refined their own unique methods for selecting astronaut crews.