The human pursuit of understanding the impact of space travel on our health has been ongoing for a long time. While we’ve managed to send astronauts on historic journeys with the hope of turning humanity into an interplanetary species, space remains a tremendously harsh and challenging environment. While humans have found ways to travel into orbit, to neighboring celestial bodies, and back safely, we are still in the process of comprehending the effects of space travel on human health, especially during long-duration missions. This research is crucial to ensure the safety of astronauts before we venture to Mars.
Drawing on NASA’s well-known study of identical twins Mark and Scott Kelly, scientists have learned that prolonged exposure to space affects blood flow to the brain, gut bacteria, frequent swelling, vision impairment, decreased bone density, and muscle atrophy in astronauts. Studies on mice conducted in conditions similar to space travel have also shown potential immune system aging and signs of brain damage.
In the largest study to date, with up to 30 scientific reports expected, experts aim to provide comprehensive answers regarding the impact of space travel on human health. The data collected is the most extensive in history, including observations and analyses of the space travel experiences of flies, worms, mice, and, of course, astronauts themselves.
Some results reaffirm existing knowledge, while others offer new insights and clarify previous findings, and even suggest improvements for future research.
“Even though we’ve made significant breakthroughs in understanding the health risks associated with space travel, we still need more studies to enhance human safety in space exploration, whether it’s missions to the moon, Mars, or venturing deeper into the universe,” says one of the authors.
One significant factor affecting the health of space travelers is the G-forces experienced at launch. Once in stable orbit, space radiation and the microgravity environment continue to impact astronauts. For instance, during a journey to Mars, astronauts will leave Earth’s protective magnetosphere and be directly exposed to cosmic radiation. Even though the journey to neighboring planets may be smooth, it will be distant, and astronauts will face one of the harshest environments that humans have ever encountered over extended periods.
The longest any astronaut has spent in the microgravity environment on the ISS is 437 days. Clearly, more data is needed to understand the effects of prolonged space living on an astronaut’s body. Many studies among the large volume of newly published reports reanalyzed or synthesized data from previous research. This is a means to improve research outcomes and optimize the data collected from costly space missions.
For example, one study analyzed data from nearly 60 astronauts and hundreds of samples collected from the GeneLab experiment to monitor changes in genes, cells, tissues, organs, and muscles of individuals upon their return from extended space travel. They discovered various changes in mitochondria – the “energy factories” inside cells responsible for converting oxygen and nutrients into energy.
Another study examined astronauts’ telomeres – the protective caps at the ends of chromosomes – before and after space travel and found differences in telomere length among astronauts; some had longer telomeres upon their return, while others had shorter telomeres.
Telomere.
Due to the limited number of astronauts and animals sent to space, there is still a lack of extensive data for in-depth analysis. This is why researchers have included flies and worms in space research. With these small organisms, researchers can scale up experiments related to space travel. These creatures also appear frequently in the newly published scientific reports.
Research on roundworms residing on the ISS showed minor changes in nearly 1,000 genes. Another study on flies revealed a decrease in the heart rate of the insects as they spent time in space.
This is the most comprehensive effort to date in studying astronaut health. With contributions from over 200 researchers from NASA and scientists worldwide, we now have a much better understanding of the human body’s vulnerability in the most challenging conditions we know.
By knowing our enemy, humanity can continue to evolve and build homes on Mars (and even more distant lands).