A newly published study holds some bad news for astronauts and potential space tourists: exposure to radiation in space may increase the risk of Alzheimer’s in astronauts.
The study, released early Monday and funded in large part by NASA, finds travel to space carries a significant increase in risk of developing Alzheimer’s.
“The possibility that radiation exposure in space may give rise to problems such as cancer has long been recognized,” said Michael O’Banion, a professor at the University of Rochester Medical Center and senior author of the study published in scientific journal Plos One. “Galactic cosmic radiation poses a significant threat to future astronauts,”
“This study shows for the first time that exposure to radiation levels equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer’s disease,” he continued.
O’Banion and his colleagues focused a specific kind of space radiation known as high-mass, high-charged (or HZE) particles. These particles – which are propelled through space at very high speeds by the force of exploding stars – come in many different forms. For this study the researcher chose iron particles. Unlikely hydrogen protons, which are produced by solar flares, the mass of HZE particles like iron, combined with their speed, enable them to penetrate solid objects such as the wall and protective shielding of a spacecraft.
“Because iron particles pack a bigger wallop it is extremely difficult from an engineering perspective to effectively shield against them,” said O’Banion. “One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.”
Space, which is filled with radiation, carries a number of risks for astronauts, although exposure to radiation is widely seen as the one of the most preventable. NASA has funded a number of studies over the past 25 years, with the hope of better understanding how humans cope with long-term exposure. As for the possibility of shielding astronauts from exposure to radiation, scientists say it is nearly impossible.
The results of the study are likely to factor into a number of upcoming missions for NASA. The U.S.-based space agency is planning manned missions to a distant asteroid in 2021 and to Mars in 2035. A round trip to the Red Planet could take as long as three years, while trips to nearby asteroids will likely take upwards of a single year. Traveling to Mars could present NASA with a number of issues to consider: a study released earlier this year found acceptable levels of radiation on Mars, possibly allowing humans to explore the planet long-term.
Meanwhile, in a posting on the agency’s Radiation Health Program website, NASA officials say they seek every precaution when launching astronauts into space.
“NASA adheres to a policy known as ALARA (As Low As Reasonably Achievable); this policy recognizes that any radiation exposure results in some risk, and therefore must be minimized,” writes the agency. “Implementing ALARA is the primary basis for real-time radiological support, and understanding and minimizing exposures from space weather events is a key to that implementation.”
The study’s release comes as questions have risen concerning whether amateur astronauts should travel to low-orbit space. Various private companies, including SpaceX and Virgin Galactic, have already announced plans to carry customers to the edge of space. With space tourism on the cusp of becoming a real possibility for people who do not have the health and fitness of a NASA astronaut, the time to think about medical guidelines could be sooner than previously imagined.