Human Spaceflight Hazards
NASA’s Human Research Program (HRP) seeks to understand specific risks associated with the hazards of human spaceflight. Learn more about these risks below.
NASA’s Human Research Program has identified several specific risks to human health associated with five hazards of spaceflight. The effects of these risks vary depending on whether humans are traveling to low Earth orbit, the Moon, or Mars. Learn more about each identified risk.
For more background, explore the five hazards of human spaceflight.
Risk of Altered Immune System ResponsesThe stresses of spaceflight can awaken inactive viruses inside the bodies of astronauts, leading to rashes and other symptoms. Ongoing work seeks to further understand changes in the immune system to better protect astronaut health.Risk of Altered Sensorimotor and Vestibular FunctionAstronauts can experience motion sickness, issues with hand-eye or gait coordination, and dizziness during gravitational changes, making it difficult to walk or operate a vehicle. Ongoing research seeks to help astronauts recover faster from these changes so they can perform tasks inside and outside spacecraft.Risk of Cardiovascular AdaptationsWeightlessness alters blood circulation and how the heart and blood vessels function, potentially increasing the risk of cardiovascular events. Research focuses on minimizing these unhealthy changes.Risk of Decompression SicknessTransitioning from a pressurized spacecraft to a lower-pressure spacesuit can cause health and mission complications when dissolved nitrogen starts to bubble within body tissues. Research focuses on developing better prevention and faster treatment options.Risk of Host-Microorganism InteractionsSkin and gut microbiomes can change in space, potentially increasing the risk of crew members getting sick. To help keep crews healthy, researchers are exploring these microbial ecosystems and how they evolve in space.Risk of HypoxiaAstronauts on future deep space missions will take steps to avoid “the bends” during spacewalks, but following those steps also elevates the risk of mild hypoxia — a condition that occurs when oxygen levels in body tissues become lower than normal. Risk of Inadequate Food and NutritionA healthy, balanced diet is an essential element of crew health and performance. Ongoing research focuses on designing enjoyable, long-lasting, and nutritious meals for deep space missions and understanding the consequences of inadequate nutrition.Risk of Injury and Compromised Performance from SpacewalksWorking in a spacesuit is challenging. In addition to cognitive fatigue and injury, crew members must also manage risks in the spacewalk environment, including decompression sickness, and low oxygen and high carbon dioxide levels. Research focuses o …