Astronauts experience several health symptoms that negatively impact vital bodily functions, and in extreme cases, vital organs may be partially or completely damaged.
Over the decades of human activity in harsh conditions outside Earth, various health risks and physiological changes have been observed in astronauts, especially during long missions that involve continuous detachment from Earth.
Due to the unforgiving space environment, which does not adhere to Earth’s laws, the primary factors threatening astronaut lives are reduced gravity’s effects and exposure to cosmic and solar radiation.
In a comprehensive report, NASA’s Human Research Program has documented these health symptoms, with the most significant being the impact of reduced gravity on bones.
During long-duration flights, bones can lose mass at an average rate of 1% to 1.5% per month, while the effect is nearly negligible during short trips.
Calcium and phosphorus make up more than half of bone material, often referred to as a “calcium bank” in the body. Similar to muscles, bones are in a constant state of formation and density change in response to external forces, such as gravity, as noted by the American Academy of Orthopaedic Surgeons.
When the effects of gravity are absent, bones gradually lose mass because they are no longer subjected to the constant mechanical load experienced on Earth.
This is an adaptive response to an entirely different environment. As bones deteriorate, they become fragile and susceptible to severe fractures under stress. It remains uncertain whether bone mass loss will eventually reach a stable stage or continue to deteriorate indefinitely.
Upon returning to Earth, astronauts’ bone mass loss ceases immediately, and a lengthy rehabilitation process begins under natural gravity conditions.
Ongoing studies investigate the nature of the lost bone, whether it can be entirely replaced, and if the new bone will be as strong as or weaker than the original.
To mitigate the effects of zero gravity on their bones and muscles, astronauts adhere to a daily exercise regimen, dedicating at least two hours on the International Space Station. Additionally, their strict diet is rich in calcium.
However, despite these efforts, damage can still occur, and there is no guarantee that the body will fully return to its pre-space condition after recovery. Furthermore, the extensive exercise hours astronauts commit to have prompted scientists to search for more effective long-term solutions.
Drugs to Prevent Bone Loss
A recent research paper published in the scientific journal “Nature” on September 18, 2023, highlights a newly discovered drug used in a study conducted on a group of 30-week-old mice to ensure the maturation of their bone structure.
The drug demonstrated high efficiency in reducing bone mass loss. Researchers from the University of California believe that this discovery could enhance the prospects of long-term space missions, including those to Mars.
The drug, known as “BP-NELL-PEG” (Bone Protein-NELL-PEG), did not exhibit any side effects. In fact, bone density increased in the mice that received the treatment, while bone density decreased in the control group, as expected in an experiment conducted aboard the International Space Station.
The drug used is a modified version of the protein “NELL-1,” bioengineered to combine with “Bisphosphonate” to create the intelligent molecule “BP-NELL-PEG,” which can precisely and efficiently target bone tissues.
Several studies conducted on a group of animals have shown that the protein has the ability to enhance the activity of cells responsible for forming bone tissues while also inhibiting cells that lead to bone fragility. The research team is eager to initiate human trials of the drug on adults undergoing specialized surgeries, such as those suffering from the degeneration of spinal discs over time, known as degenerative disc disease.
In an interview with the “Health at the University of California” organization, Dr. Chia Su, a plastic surgeon and the leader of the research team, expressed her pride in the results they have achieved. She stated that these findings hold immense promise for the future of space exploration, particularly for human missions that involve months of working far away from Earth.