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After nearly half a century in near-Earth orbit, humanity is setting its sights on the Moon once again, with Mars looming as the next frontier. As we venture further into space, there is a growing need for comprehensive research on how the unique stresses of space travel impact the human body.
The iconic moment of Neil Armstrong’s moonwalk marked a significant milestone in space exploration. During the Apollo 11 mission, ECG sensors monitored Armstrong’s heart rate from over 350,000 kilometers away, emphasizing the potential and limitations of space medicine. While meticulous preparation and real-time monitoring are possible, the vast distance from Earth poses challenges in case of serious medical emergencies.
Life on Earth has evolved to thrive in diverse environments, adapted to gravity and protected from cosmic radiation. However, as we break away from these familiar conditions with space travel, questions arise about the effects on our biology after four billion years of evolution.
The field of space medicine has evolved alongside space exploration, aiming to answer critical questions about the impact of weightlessness, cosmic radiation, and other factors on the human body. The knowledge gained from sending laboratory animals into space and manned missions in the 1960s laid the foundation for understanding the short-term effects of space travel. However, with ambitious plans to return to the Moon and eventually reach Mars, new challenges require further exploration.
Unraveling the Mysteries of the Immune System
Lisa Westerberg, a researcher at Karolinska Institutet’s Department of Microbiology, Tumour, and Cell Biology, is investigating the impact of space travel on the immune system. Recent findings suggest that approximately half of all astronauts become more susceptible to infections during and after their stays on the International Space Station (ISS). Reactivation of latent viruses is also observed, indicating a form of immunodeficiency.
Westerberg’s hypothesis is that weightlessness hinders the circulation of immune cells in the body, affecting their ability to move efficiently in and out of tissues. Experiments simulating weightlessness on Earth have shown changes in the gene expression of T cells, a crucial component of the immune system.
The hope is that understanding how the immune system deteriorates in space will lead to effective treatments. Westerberg emphasizes the potential use of existing immunological drugs once the mechanisms are better understood. Continuous monitoring of astronauts’ immune systems during long space journeys is crucial, and Westerberg advocates for the development of compact instruments for this purpose.
Muscles, Skeletons, and the Challenges of Cosmic Radiation
The weakening of muscles and the skeleton due to the absence of gravity is a well-known challenge in space travel. Rodrigo Fernandez Gonzalo, a researcher at Karolinska Institutet’s Department of Laboratory Medicine, explores the mechanisms behind muscle deconditioning. Understanding the genetic changes during muscle mass loss is not only crucial for long space missions but also holds significance for treating muscle-related diseases on Earth.
Gonzalo acknowledges the psychological importance of daily exercise for astronauts on the ISS. While there is a desire to make exercises more efficient, the mental well-being of astronauts during these routines remains a priority.
The unpredictable factor of cosmic radiation poses a significant challenge for future space missions. Gonzalo points out that exposure to solar particle events and galactic cosmic rays, inevitable during trips to the Moon and Mars, could lead to increased risks of cancer and other damage. Advanced solutions, such as drugs enhancing resistance to radiation, may be necessary for long-term space exploration.
Fluid Redistribution and Respiratory Challenges
Weightlessness alters the distribution of fluids in the body, leading to changes in appearance, such as thin legs and a swollen face. While the body adapts by eliminating excess fluid during the initial days, challenges arise in respiratory health. Dust and particles, not subject to gravity, remain suspended in the air and can enter the lungs, potentially causing inflammation and impaired lung function.
Lars Karlsson, a researcher at Karolinska Institutet’s Department of Physiology and Pharmacology, explores how the measurement of nitric oxide (NO) can diagnose airway inflammation in astronauts. Low-pressure tests simulating lunar or Martian conditions have been conducted on the ISS, considering the potential effects on NO levels in exhaled air.
Karlsson’s research also delves into blood composition and blood pressure regulation, crucial for astronauts re-exposed to gravity after a period of weightlessness. Centrifuges, providing artificial gravity, may offer a solution to prevent blood pressure-related issues.
Challenges Beyond Earth’s Immediate Reach
While space travel poses its set of challenges, the ability to address medical incidents remains a concern. Unlike expeditions in Antarctica, where doctors might need to perform self-surgery, space missions carry the risk of prolonged isolation and limited access to medical care. With upcoming lunar and Mars missions, the importance of comprehensive medical solutions becomes even more pronounced.
Despite the risks, some researchers express their fascination with space. Lars Karlsson, who twice applied to become an astronaut, emphasizes the privilege of devoting research to such an intriguing subject. Others, like Lisa Westerberg, find their calling in studying space from afar, acknowledging the complexities and challenges posed by the extreme conditions beyond our planet.
As humanity embarks on a new era of space exploration, the collaboration between researchers and space agencies becomes paramount. The quest for answers to how the human body copes with the challenges of extended space journeys continues, paving the way for future missions to the Moon, Mars, and beyond.
