An international research team ran a protracted experiment on board the International Space Station to investigate how space radiation affects mouse embryonic stem cells. Scientists will be able to make a more accurate estimate of the risks and benefits of space radiation for future of human spaceflight missions with the help of their research.
On August 18, 2022, the team published the results of their research in the journal Heliyon.
By sending frozen mouse embryonic stem cells to the International Space Station, subjecting them to space radiation for more than four years, and measuring the biological effect by looking at chromosome aberrations, the team was able to directly quantify the biological impact of space radiation. The results of their experiment show for the first time that the effects of space radiation on living things are very close to what scientists had thought based on observations of the radiation’s physical properties.
Long-duration manned missions to distant planets like the Moon and Mars are becoming more likely.However, space radiation continues to be a barrier to manned exploration. In-depth research has been conducted by scientists to quantify the physical doses of space radiation and better understand how it affects the human body. Given that space radiation is made up of numerous types of particles with various energies and that astronauts are continuously exposed to low-dose rates of radiation, the results of the majority of research conducted up until this point on Earth rather than in space suffered as a result. On Earth, the space environment cannot be perfectly simulated.
Takashi Morita, a professor at the Graduate School of Medicine at Osaka Metropolitan University, stated that “our study aims to address the shortcomings of previous ground-based experiments by performing a direct quantitative measurement of the biological effect of space radiation on the International Space Station and comparing this real biological effect with physical estimates in the ground-based experiments.” “The results reduce uncertainties in risk evaluations of human space flight missions.”
About 1,500 cryotubes containing extremely radiosensitive mouse embryonic stem cells were manufactured by the researchers and launched into orbit. Their study took seven years to complete before it was launched, four years to complete after it was launched, and five years to analyze the results. Professor Morita added, “It was challenging to design the experiment and interpret the data, but we successfully acquired quantitative results linked to space radiation, satisfying our initial purpose.”
The scientists intend to advance their research in the future. Since human cells are considerably better suited for evaluating future of human spaceflight risk and it is simpler to detect chromosome abnormalities, Professor Morita said, “We are exploring employing human embryonic stem cells rather than mouse embryonic stem cells in future studies.” Future research may possibly involve sending individual mice or other test animals into space to study their genomic abnormalities. As Professor Morita put it, “Such deep space experiments can further contribute to reducing uncertainty in risk estimates of extended human voyages and stays in space.”
Kayo Yoshida, Akane Kizu, Kohei Kitada, and Takashi Morita from Osaka Metropolitan University are part of the research team. Megumi Hada and Premkumar Saganti from Prairie View A&M University, Kiyomi Eguchi-Kasai and Toshiaki Kokubo from the National Institute of Quantum Science and Technology, Takeshi Teramura from Kindai University, Sachiko Yano and Aiko Yama
The Japanese Ministry of Education, Culture, Sports, Science, and Technology, as well as JAXA and JSF, helped fund this study.
