Astronauts who took part in the Apollo missions could have faced more heart problems due to their exposure to galactic cosmic rays, according to a recent study in Scientific Reports.
The Apollo program was NASA’s human spaceflight project that first landed Neil Armstrong and Buzz Aldrin on the Moon in July 1969. Between 1961 and 1972, the program launched 24 men into deep space, of which eight are now deceased, and others who only flew into low-Earth orbit.
Researchers at Florida State University found that 43 percent of deceased Apollo astronauts who flew into deep space died from a cardiovascular problem. That’s nearly five times higher than astronauts who have traveled in low-Earth orbit or did not fly.
Although 31 percent of people die from cardiovascular diseases worldwide, these recent findings are particularly strange considering that astronauts are highly educated, have access to the best medical care, and typically have healthy lifestyles. The only difference between these men and the wider population was their exposure to deep space radiation, particularly in the form of high-energy ions like 56-Fe.
“We know very little about the effects of deep space radiation on human health, particularly on the cardiovascular system,” lead researcher Professor Michael Delp said in a statement. “This gives us the first glimpse into its adverse effects on humans.”
In a push to test this hypothesis, the scientists also exposed groups of mice to the same type of radiation for more than six months that the Apollo astronauts experienced. They found that the mice's arteries showed signs of damage that can lead to atherosclerotic cardiovascular disease.
“What the mouse data show is that deep space radiation is harmful to vascular health,” Delp added.
However, NASA have questioned the findings, arguing that the current data and sample size is too limited, according to Reuters. It's also worth considering that the mice were "blasted" with radiation for six months – what the researchers say is the equivalent of 20 human years. The Apollo astronauts would have only have been out of Earth's magnetic shield for a matter of days, so it could be considered a jump to say there's a direct link between these few days of exposure and cardiovascular disease.