In February 2020, astronaut Christina Koch made history by completing an 11-month mission aboard the International Space Station (ISS). This feat marks the longest single spaceflight by a woman. The extended duration of her stay on the ISS is part of NASA’s preparations for future missions to the Moon and Mars.
Necessity of the Mission
The majority of data available until now has been collected from male astronauts. However, male and female bodies respond differently to space travel and can develop health conditions at different rates. Therefore, Koch’s mission aims to fill this gap, study the impact of long space travel on the female body, and prepare for potential issues.
The Five Hazards of Space Flight
NASA classifies the impact of spaceflight on humans into five broad hazards.
Radiation Exposure in Space
All space flights take place outside Earth’s protective magnetic field, hence, the radiation levels are much higher compared to those on the ISS, which is just within Earth’s protective atmosphere. Even then, radiation on the ISS is 10 times higher than on Earth. Exposure to such high levels of radiation increases cancer risk, damages the central nervous system, alters cognitive function, reduces motor function, and provokes behavioural changes.
Isolation and Confinement
Living in the cramped quarters of a spacecraft over a long period can lead to behavioral issues among astronauts. This situation is even worse when combined with sleep loss, circadian desynchronization, and work overload.
Communication Delay Due to Distance from Earth
As the distance of space flight increases from Earth, communication delays also increase. For instance, there will be a communication delay of 20 minutes during space travel to Mars.
| Hazard | Impact |
|---|---|
| High radiation levels | Increased risk of cancer, damage to the central nervous system |
| Isolation and confinement | Behavioral issues, sleep loss, circadian desynchronization, work overload |
| Communication delay | Communication delay of 20 minutes during space travel to Mars |
The Impact of Different Gravitational Pulls
Different planets have different gravitational pulls. On Mars, for example, astronauts would need to live and work in three-eighths of Earth’s gravitational pull. What’s more, transitioning from one gravity field to another can be quite intense.
Hostile/Closed Environments
NASA has found that the ecosystem inside a spacecraft plays a significant role in an astronaut’s daily life. Microbes can change characteristics in space, and microorganisms that naturally live on our bodies can be transferred more easily from person to person in closed habitats.
Impact on Human Health
Spaceflight results in a range of health impacts, including weightlessness leading to osteoporosis, shifts in body fluids causing vision problems, decreased body mass, increased folate, changes in telomeres, and potential gene mutations.
Weightlessness and Osteoporosis
Without gravity acting on the body, bones lose minerals at a rate of over 1% per month. This is compared to a rate of 1% to 1.5% per year in elderly people on Earth. Astronauts could also be at greater risk of osteoporosis-related fractures later in life, and this bone loss might not be correctable with rehabilitation.
Micro-gravity and Osteoporosis
Osteoporosis is a condition that weakens bones, making them fragile and more likely to break. In microgravity conditions, the rate of osteoclast (bone-breaking cells) formation increases, leading to bone loss and osteoporosis.
Telomeres and Spaceflight
Telomeres, the caps that protect our chromosomes from damage, get longer during spaceflight. Longer telomeres are associated with fewer age-related problems.
Body Mass and Folate Levels in Orbit
Spaceflight can lead to decreased body mass. On the other hand, folate, one of the B-vitamins needed to make red and white blood cells, convert carbohydrates into energy, and produce DNA and RNA, increases in orbit.
Spaceflight-Triggered Gene Mutations
The stresses of space travel can alter the biological pathways within cells. This process can cause cells to eject DNA and RNA and potentially initiate gene mutation.
