For over half a century, NASA’s Human Research Program (HRP) has dedicated itself to understanding the effects of space travel on the human body. The knowledge gained from these studies is crucial for developing strategies, procedures, and technologies to ensure the safety and well-being of astronauts during their missions. This research informs the design of spacecraft, the improvement of spacesuits, and the creation of effective medical standards, fitness programs, and training protocols. Ultimately, it’s about preparing humans for the unique challenges of space. But what exactly is A Person Who Travels In Space Is Called? The answer is, most commonly, an astronaut.
Understanding how spaceflight impacts humans is especially vital as we venture beyond low-Earth orbit to destinations like the Moon and Mars. The Artemis program, NASA’s initiative to land the first woman and the next man on the Moon, relies on innovative technologies and extensive research to explore the lunar surface safely and effectively. As NASA plans for extended missions, understanding the long-term effects of spaceflight becomes paramount.
Astronauts like Scott Kelly and Christina Koch, who spent nearly a year in space, have provided invaluable data. Scott Kelly’s participation in the unique Twins Study, where he was compared to his identical twin brother Mark on Earth, yielded insights into the physiological and psychological changes that occur during prolonged spaceflight.
NASA’s ongoing research aims to illuminate how the human body adapts to the spaceflight environment over extended periods, which is essential for future deep space missions.
The Five Hazards of Human Spaceflight: The RIDGE Acronym
What exactly happens to the body in space, and what are the associated risks? Are these risks different for short-term space station missions versus long-term Mars missions? The answer is a resounding yes. NASA has identified five key hazards of human spaceflight, summarized by the acronym “RIDGE”: Space Radiation, Isolation and Confinement, Distance from Earth, Gravity Fields, and Hostile/Closed Environments.
Space Radiation
On Earth, our planet’s magnetic field and atmosphere shield us from most of the harmful particles that constitute space radiation. However, in space, astronauts face increased and varied levels of radiation exposure. The three main sources of this radiation are particles trapped in Earth’s magnetic field, solar energetic particles from the Sun, and galactic cosmic rays.
The aurora is a visual representation of Earth’s magnetic field deflecting harmful solar radiation.
Reducing the risks associated with radiation exposure is a significant challenge, as some space radiation particles, particularly galactic cosmic rays, are difficult to shield against. Increased radiation exposure can lead to both short-term and long-term health consequences, including an increased risk of cancer and degenerative diseases like heart disease and cataracts. Furthermore, research suggests that the type of radiation found in space may have a greater impact on health outcomes compared to radiation on Earth.
The Key: NASA’s strategy to mitigate the health risks of space radiation involves implementing shielding, radiation monitoring, and specific operational procedures. As missions to the Moon and Mars will be significantly longer than typical space station missions, the total radiation exposure and associated health risks are expected to increase.
NASA is developing advanced radiation detectors to monitor and characterize the radiation environment, providing more accurate estimates of the radiation doses received by astronauts. Scientists and engineers are also optimizing operational procedures to utilize vehicle stowage and materials to effectively reduce radiation exposure.
Isolation and Confinement
Astronauts chosen for space station missions undergo rigorous selection, training, and support to ensure their ability to function effectively as a team during their missions. Crews for Moon or Mars missions will face even more stringent assessments and preparation due to the greater distances and longer durations involved.
Ensuring astronauts get sufficient quality sleep is crucial, as their circadian rhythms can be disrupted by factors such as varying dark and light cycles, a confined and noisy environment, and the stress of prolonged isolation.
ESA (European Space Agency) Samantha Cristoforetti replaces centrifuge components inside the Columbus laboratory module’s BioLab, a research facility that studies the effects of space and radiation on micro-organisms
BioLab is used to study the effects of the space environment on living organisms.
Fatigue is another concern, given the demanding workloads and shifting schedules astronauts face. To combat crew boredom, NASA considers the types of activities astronauts will engage in during long-duration missions.
Effective communication and understanding among crew members are essential, and changes in morale and motivation are possible over the course of a mission.
Research using spaceflight analogs on Earth has demonstrated the importance of both the duration and nature of the confined and isolated experience. The more restricted the space and the less contact with the outside world, the higher the likelihood of behavioral, cognitive, or psychiatric issues.
The Key: NASA has extensive experience studying individuals in isolated and confined environments and has developed technologies and methods to address potential problems.
Distance from Earth
The space station orbits 240 miles above Earth, while the Moon is 1,000 times farther away. Mars, on average, is a staggering 140 million miles from Earth. The significant communication delays experienced on Mars, which can be up to 20 minutes each way, necessitate that astronauts can solve problems and make decisions independently, without immediate support from mission control.
Astronauts practice procedures in simulators to prepare for the isolation of space travel.
The selection of food and medicine for multi-year missions without access to resupply is another critical consideration. Unlike space station crews, who receive regular shipments from Earth, astronauts traveling to Mars must bring all necessary supplies.
The Key: NASA leverages its experience on the space station to determine the types of medical events that occur in space over time and the skills, procedures, equipment, and supplies required for future missions to the Moon and Mars.
Gravity Fields
Astronauts on a Mars mission will encounter three different gravity fields: weightlessness during the six-month journey between planets, approximately one-third of Earth’s gravity while on Mars, and Earth’s gravity upon their return.
Transitioning between gravity fields can affect spatial orientation, coordination, balance, and locomotion. Some astronauts experience space motion sickness.
Landing on Mars can be challenging as astronauts adapt to the gravity of another celestial body. The shift from weightlessness to gravity can cause post-flight orthostatic intolerance, where astronauts struggle to maintain blood pressure when standing, potentially leading to lightheadedness and fainting.
A view of Earth taken from a distance by the lunar module during the Apollo 11 Mission.
The vast distance of space travel necessitates careful planning and resource management.
NASA has learned that weight-bearing bones lose an average of 1% to 1.5% of mineral density per month in space without Earth’s gravity. Muscle mass also decreases more rapidly in microgravity without proper diet and exercise. Fluid shifts in the body can put pressure on the eyes and cause vision problems. There’s also an increased risk of kidney stones due to dehydration and calcium excretion from bones.
The Key: By studying how the body changes in weightlessness and upon returning to Earth’s gravity, NASA is developing countermeasures to protect astronauts during Mars missions.
Hostile/Closed Environments
The ecosystem inside a spacecraft significantly impacts astronauts’ daily lives. Microbes can change their characteristics in space, and those naturally residing on the human body spread more easily in closed habitats like the space station. Stress hormone levels are elevated, and the immune system is altered, potentially increasing susceptibility to allergies and illnesses.
Earth-based analogs cannot perfectly replicate the spaceflight environment, making them insufficient for studying human immune system reactions in space. However, NASA-funded Antarctic analog studies may offer insights into how certain spaceflight stressors affect the immune system. Spaceflight is known to alter the immune system, and further research is needed to determine if this may lead to autoimmune issues.
Microgravity affects the distribution of fluids within the human body.
Beyond the environment’s impact on the immune system, every detail of living and working quarters must be carefully designed.
The Key: NASA uses technology to monitor air quality on the space station, ensuring a safe and breathable atmosphere free from contaminants. Thermal control systems maintain comfortable temperatures.
Conclusion
NASA is actively addressing these risks and working to overcome the challenges of human spaceflight. Data collected from laboratories, ground analogs, and space station missions will provide deeper insights and pave the way for longer missions.
On upcoming Artemis missions to lunar orbit and the Moon’s surface, even more data will be gathered. On future long-duration missions to the Moon and Mars, astronauts – the individuals who venture into the vastness of space – will benefit from years of research ensuring they not only survive but thrive on their spacefaring journeys.
