A new study has found that astronauts involved in the Apollo space programme experience higher rates of cardiovascular-related deaths than those who never ventured beyond low-Earth orbit – the cause of which is likely to be exposure to deep space radiation.
The paper, published in Scientific Reports by Florida State University (FSU) Dean of the College of Human Sciences Professor Michael Delp, notes that the men who travelled into deep space as part of the Apollo missions were exposed to very high levels of galactic cosmic radiation.
And it is this exposure to radiation that is now manifesting itself as cardiovascular problems, which could have deep implications for future missions beyond low-Earth orbit, including those to Mars.
The Apollo space programme ran from 1961 to 1972, with 11 manned flights into space – nine of which flew beyond Earth’s orbit into deep space. This study is the first to look at the mortality rate of these Apollo astronauts.
“We know very little about the effects of deep space radiation on human health, particularly on the cardiovascular system,” Delp explained. “This gives us the first glimpse into its adverse effects on humans.”
The research is of particular interest as the US, other nations and private organisations continue to make plans for deep space travel. Elon Musk ‘s SpaceX, for example, has proposed landing humans on Mars by 2026. And NASA plans to launch orbital missions around the moon from 2020 to 2030.
While astronauts have access to top medical care, the Apollo mission members did experience vastly different environmental conditions when they travelled into deep space – conditions that, the study has found, have affected their health.
The study revealed that 43% of deceased Apollo astronauts died from cardiovascular problems – four to five times higher than non-flight astronauts and those who travelled in low-Earth orbit.
A total of 24 men travelled into deep space as part of the Apollo lunar missions – eight have died; seven were included in the study (the eighth died after the data analysis had been completed).
Delp’s team carried out an animal test as part of the research, exposing mice to the type of radiation that Apollo astronauts would have experienced. After six months, or the equivalent of 20 human years, the mice showed damage to arteries that is known to lead to the development of atherosclerotic cardiovascular disease.
“What the mouse data show is that deep space radiation is harmful to vascular health,” Delp said. He is currently working with NASA to carry out further studies on the Apollo astronauts with regard to their cardiovascular health.