Forever Changed: Why Governments Must Protect the Harm of Space Radiation on the Human Genome

What happens when the human genome is exposed to an unfamiliar environment? As space exploration continues to expand and scientific barriers are broken through, one macroscopic concern remains a consideration on a molecular level. Many people are aware of some effects of space travel; it is widely known and proven in many studies that space travel causes muscle loss, decreased bone density, and dizziness from disorientation. However, the biological effects of space travel reach deep into our genome and alter our genetic code. In fact, the human genome is highly sensitive to environmental change, and space’s environment is not only relatively new and unknown, but one of the most extreme as well.

Studies such as the NASA Twins Study, conducted from 2015 to 2016, and the Mars500 Project, from 2007 to 2011, have revealed that space travel can cause shortened telomeres and increased DNA instability, resulting in altered gene expression. In the long term, astronauts may experience immune system dysfunction, DNA repair issues, neurological disorders, and numerous other health problems. Specifically, these changes that affect an astronaut’s internal systems make them more likely to develop conditions such as obesity and diabetes.

Despite these findings and severe risks, even leading space nations such as the USA, China, and Russia lack thorough national policies that address astronauts’ genetic safety. This leads to most federal funding to space programs being allocated towards space operations and infrastructure, while only a very small percentage of funding goes towards protecting astronauts' health or research into this issue. By creating enforceable and comprehensive national health standards for astronauts and investing more into the impacts on genetic research, governments can ensure the protection of our brave astronauts with a full understanding of the biological costs.

In a study done by the NASA Human Research Program in 2020 on the radiation risks to astronauts in deep space, exposure to extreme galactic cosmic radiation (GCR) was found to cause DNA strands to break and a 3 percent increase in radiation-induced death from cancer. Found in GCR are high atomic number and energy (HZE) particles, which are heavy and highly energetic ions, composed of the nuclei of iron, carbon, oxygen, and silicon. These HZE particles, found only in space’s extreme conditions, penetrate past human tissue defenses and directly onto the genome. The dense ionization of these particles causes DNA strands to break, making it harder for cells to repair, and in turn leads to mutations, cancer cell formation (oncogenesis), or cell death. 

Radiation levels are measured in millisieverts (mSv), which directly reflects the impact of radiation on human tissue. Astronauts travelling in space experience high amounts of radiation exposure. Just six months on the International Space Station (ISS), astronauts, on average, are exposed to 50 times more radiation than an average person on Earth. While NASA does have a career limit of 600 mSv for its astronauts, cancer risks sharply increase at over 500 mSv and may cause Acute Radiation Syndrome (ARS) if the radiation doses continue to increase. These symptoms include low long-term immunity from genetic harm and possible neurological damage.

The most important thing is that many of these genetic damages caused by radiation are known to be irreversible. In the NASA Twins Study, while 92 percent of gene expression returned to normal, almost all DNA strand breaks and chromosomal aberrations (structural or numerical change) were irreversible. This means some damage done by radiation didn’t return to normal, leading to permanent damage and risks. The NASA Twin Study was a study done by NASA in which Scott Kelly spent a year on the ISS, while his identical twin, Mark Kelly, remained on Earth to study the impacts on the human genome. One of the most important and scariest findings of the study was the shortening of Scott's telomeres, the protective ends of chromosomes. Other DNA mutations were also observed, such as chromosomal inversion and translocation, increasing risks of unpredictable and sudden changes in the body, while decreasing the body's immune system and ability to respond to disease.

So, what have countries and space agencies done to protect astronaut health related to genetic risks and radiation? The answer is not much. In the United States, the TREAT Astronauts Act, passed in 2016, provided astronauts with lifetime medical care and gave NASA the authority to monitor the health of astronauts. However, there is little focus on genetic changes such as DNA damage and chromosomal instability. Instead, most funding for research is focused on the muscular and cardiovascular impacts of space travel.

The European Space Agency (ESA) runs the Space Radiation Superconducting Shield program to measure radiation doses aboard the ISS. While this may seem like a step towards protecting astronauts’ genes from radiation, its policy focus does not include regulatory policies and is not primarily focused on genetic damage. According to the program's website, its main objective is centered around engineering progress and dosage estimations rather than genomic tracking and medical procedures.

Finally, the Japan Aerospace Exploration Agency (JAXA) launches health experiments to study the impacts on the human genome. Before each mission, astronauts are briefed on their expected radiation levels. However, once again, there is a lack of formalized genetic health protection and policy initiatives. Astronauts are not legally required to be briefed on genetic risk, and participation is voluntary with no required genetic monitoring. 

As space missions travel further into space and astronauts’ genomes are put at an even greater risk with radiation, national governments worldwide must decisively act to create national policies and ensure the safety of astronauts at a genetic level. First, rather than the current system in many countries of voluntary genetic health monitoring, governments must have mandatory health monitoring. This would enable space agencies to track genetic instability and DNA strand breaks. With this policy, unexpected risks may be prevented by detecting possible diseases before it’s too late. Governments must also mandate private companies such as SpaceX and Blue Origin to comply with these policies. 

Secondly, the only country in the world that provides astronauts with lifelong healthcare is the United States. Through the TREAT Astronauts Act, NASA guarantees lifelong health care for astronauts. While the program lacks protections for genetic health, countries worldwide should follow a model after the United States and introduce policies that grant their astronauts this protection. 

Lastly, and most importantly, there should be more funding towards the genetic protections of astronauts. Governments should dedicate a fixed percentage of the space budget towards genetic research, mission design, and health care. Investments towards the genetic protection of astronauts could include developing pharmaceuticals to mitigate DNA damage, incorporating gene-editing techniques such as CRISPR as a means of repairing DNA damage, and training artificial intelligence to predict personalized genetic risks before a mission. Investments towards genetic research should also be allocated towards more genetically friendly spacecraft designs. Current spacecraft have limited research on their genetic effects, and limitations with radiation protection are known to the public. Although in an early process of research, components of spacecraft could include radiation shielding, which would lessen the direct impact of radiation on genomes. Engineering these physical defenses can prevent chronic illnesses and cancer risks from radiation exposure on missions. 

As our space discoveries continue to skyrocket at an unprecedented rate, national governments’ commitment to astronaut protection must be matched on the same level. National governments have the responsibility to fund health care for astronauts, research possibilities of mitigating DNA damage, and implement and regulate policies protecting astronauts. Our ability to venture further into space depends on how well we can protect the astronauts who make it possible.