Is exposure to deep space radiation killing off Apollo-era astronauts?
Florida State University ProfessorMichael Delp has identified a link between deep space radiationexposure, and a high rate of mortality due to cardiovascular problems in astronauts who flew beyond low-Earth orbit (LEO) during the Apollo program. Research based on the discovery could beused to safeguard future astronauts undertaking the next phase of mannedspace exploration.
Numerous studies have been carried outaimed at understanding and mitigating the health risks to astronauts operating inlow-Earth orbit (LEO). Research in the area has led to the development of equipment and exercise regimes designed to maintain the health of astronauts operating in microgravity environments such as that prevailing aboard the International Space Station (ISS).
However, as nations across the globe,including the United States, China, and even commercial entities suchas SpaceX turn their gaze back towards the sphere of manned deep space exploration, a different form of danger must be considered — the threat posed by cosmic radiation.
LEO astronauts, such as those that make up the crew of theISS are largely protected from deep spaceradiation thanks to the protective influence of Earth's magnetosphere, which works to deflect the dangerous particles emanating from our Sun.
Members of the Apollo program that flewbeyond LEO had no such protection, and were fully exposed to thedeep space radiation. Space exploration by its very nature requires pioneers to step into the unknown, and cope with environments that our species has not evolved to survive. The best that we can do to prepare for future missions is to learn from the experiences of those brave souls who have ventured beyond the microgravity environment.
Delp's study went one step further by observingthe cause of death for Apollo astronauts in order to determine therisk to future human explorers. Between 1968 and 1972 nine mannedApollo missions flew beyond LEO into deep space. Of the 24 astronautsthat crewed the spacecraft, 8 have passed away.
Upon reviewing their causes of death, theprofessor noted that 43 percent of the Apollo astronauts had fallen victimto cardiovascular issues, a rate five times higher than ground crewand astronauts who never passed beyond Earth's protectivemagnetosphere. According to Delp, it is possible that thecardiovascular defects result from an exposure to cosmic radiation.
To explore his theory further, Delpsubjected laboratory mice to radiation doses similar to those which would beabsorbed by astronauts operating in deep space. It was discoveredthat six months after exposure, which would be the equivalent of 20human years for the mice, the subjects began to exhibit signs ofartery impairment. Such degradation in a human patient could in timelead to the onset of atherosclerotic vascular disease.
Having provided evidence for a linkbetween exposure to cosmic radiation and deterioration to vascularhealth, Delp is now working with NASA to develop methods by which wemay be able to counteract the effect of deep space radiation. Antioxidants are being examined as oneline of potential treatment, the administering of which could theoretically protect a space explorer's bloodvessels from damage due to oxidant stress.
The capacity to mitigate the dangers tofuture astronauts posed by cosmic radiation will be of vitalimportance if NASA is to progress with its mission to Mars, the nextstep of which involves the development of long term habitats orbitingin cislunar space.
Source: Florida State University