The plan to land Humans on the Moon by 2024 represents an aspiring milestone in the broader quest to explore deep space and, ultimately, use Earth's natural satellite as a stepping-stone to Mars. However, to accomplish these goals, we need to understand the impact of long duration space travel on human health. This requires extensive research and innovative solutions to address the unique challenges of living and working in deep space.
Testing in Low Earth Orbit
Low Earth orbit (LEO) has been a proving ground for human
spaceflight since Yuri Gagarin's historic journey in 1961. However, missions to
the Moon and Mars require prolonged exposure to space conditions, posing
significant risks to human health. While data from previous lunar missions are
limited to a few days at a time, a trip to Mars would involve several months of
travel.
To better understand the effects of space on human biology,
researchers rely on various analogs and simulators. The Translational Research
Institute for Space Health (TRISH) is developing a Mars mission simulator to
study the physiological impacts of long-duration space travel. Meanwhile,
NASA's Human Research Program uses the International Space Station (ISS) to
observe how the human body adapts to living in space for extended periods.
The ISS, orbiting about 250 miles (400 kilometers) above
Earth's surface, provides valuable insights into how space conditions affect
biological systems. Despite its relative proximity to Earth, astronauts on the
ISS experience changes in muscle mass, bone density, and immune response, among
other effects. NASA's famous Twins Study, which tracked identical twin brothers
(Scott and Mark Kelly), provided critical data on space-induced biological
changes. The study revealed that while some effects, like shortened telomeres
and DNA damage, could persist after returning to Earth, others gradually
resolved over time.
Moving Out into Deep Space
While research in LEO has been invaluable, it doesn't fully
prepare us for the challenges of deep space exploration. The ISS is protected
by Earth's magnetosphere, whereas missions to the Moon and Mars will expose
astronauts to galactic cosmic radiation. This type of radiation is particularly
concerning due to its potential to damage DNA and increase the risk of cancer.
Beyond radiation, deep space missions will introduce other
stressors, including isolation and confinement. NASA's Human Exploration
Research Analog (HERA) at the Johnson Space Center simulates these conditions,
providing insights into how astronauts might cope with extended missions.
Additionally, studies of people living in remote environments like Antarctica
offer a glimpse into the psychological and physiological effects of isolation.
Gravitational changes also pose a significant challenge.
Astronauts traveling to Mars would experience transitions from Earth's gravity
to weightlessness, then to Mars' one-third gravity, and back again. These
shifts can affect coordination, orientation, and overall movement. The
resulting physical stress may also contribute to motion sickness and other
health issues.
Innovative Solutions for Deep Space Challenges
To address the unique risks of deep space travel,
researchers are developing innovative tools and techniques. TRISH is exploring
complex in vitro models (CIVMs) to understand how human tissues respond to
cosmic radiation. These models include artificially engineered 3D cell
cultures, organs-on-chips, and bioprinted tissues, which replicate key aspects
of human biology. By using diverse cell samples that represent a range of
traits, including sex, gender, and ethnicity, TRISH aims to identify the most
effective treatment plans for potential medical emergencies during deep space
missions.
The ultimate goal is to ensure the safety and well-being of astronauts as they venture farther from Earth. With missions to the Moon and Mars on the horizon, researchers are racing to answer the critical questions about human health in deep space. As these efforts progress, humanity moves one step closer to exploring the final frontier.
