Aug 6, 2019

The unknown risks of radiation in space

Illustration: Aïda Amer/Axios

A lack of hard data on the effects of radiation on astronauts — and how to mitigate the health threat — could set back NASA's plans to send people to Mars in the 2030s, experts tell Axios.

Why it matters: Radiation, particularly in the form of high-energy galactic cosmic rays, can increase an astronaut's risk of developing cancer, cardiovascular issues and even cognitive deficits.

  • At the moment, NASA places a strict limit on the amount of radiation astronauts can be exposed to in their lifetimes, but a trip to Mars could require that limit to be exceeded.

The big question: Even though researchers have been studying the effects of radiation in lab experiments for years, they still don't know how radiation exposure on a months-long trip to Mars might impact astronauts.

What's new: In a study this week in the journal eNeuro, researchers exposed mice to a chronic, low dose of radiation over about 6 months, attempting to mimic the amount of radiation astronauts might experience during a flight to the red planet.

  • They found the radiation exposure could cause anxiety, memory issues and difficulty with decision-making.

But, but, but: Some researchers say there are broader limitations to characterizing the threat posed by radiation in space.

  • The type of radiation used for the new study isn't the same as cosmic rays, and the overall amount of radiation in the study is higher than what people would experience during a trip to Mars, Francis Cucinotta, a radiation researcher at the University of Nevada, Las Vegas told Axios in an interview.
  • Mice and rats in general also aren't perfect analogues for astronauts, and there isn't a sure-fire way of mimicking the exact radiation a person experiences in space on Earth.
  • It's not just about radiation on its own. Scientists are worried about a number of health concerns — including nutrition, sleep deprivation and muscle loss — that, in combination with radiation, could present serious health issues that astronauts will need to deal with millions of miles from Earth.
"We may never know until we send people, and they are going to be guinea pigs. These people are going to take a chance."
— Dorit Donoviel, Baylor College of Medicine, to Axios

What to watch: NASA has looked into countermeasures like medication that could protect astronauts from the damage caused by radiation during a trip to Mars. However, Donoviel says that the agency needs to invest more heavily in those efforts to ensure the missions have the best chance of success.

The bottom line: The health threat posed by radiation is a serious one, and NASA may need to move more quickly to find effective ways to mitigate it if it wants to send humans to Mars in the coming years.

For those willing to risk their lives in myriad ways to go to space, radiation may be a secondary concern at best, even if it's a deal-breaker for NASA, former astronaut Michael Lopez-Alegria tells Axios.

  • “You’re taking a lot more immediate, and much more visible, kinds of risks by launching to space that I think that radiation — at least for me — didn’t enter into the equation very prominently," Lopez-Alegria said.

The big picture: Astronauts aren't the only professionals with this kind of drive to continue doing their jobs at all costs. Elite athletes, for example, push past pain and injury in order to continue competing.

  • Lopez-Alegria — who has spent more than 250 days in space — explained that because the risks posed by radiation are more likely to affect someone later in life, it isn't something astronauts tend to worry about.

Details: Overall, NASA won't allow astronauts to receive a lifetime radiation dose that would raise their risk of contracting a fatal cancer by more than 3%, but the total acceptable dose differs depending on who you are.

  • Female astronauts, for example, have a lower threshold than men due to the way NASA calculates risk, leading some to say the agency's limits are discriminatory because it restricts the amount women can fly.

Go deeper

Coronavirus dashboard

Illustration: Aïda Amer/Axios

  1. Global: Total confirmed cases as of 3 a.m. ET: 5,410,228 — Total deaths: 345,105 — Total recoveries — 2,169,005Map.
  2. U.S.: Total confirmed cases as of 3 a.m. ET: 1,643,499 — Total deaths: 97,722 — Total recoveries: 366,736 — Total tested: 14,163,915Map.
  3. World: White House announces travel restrictions on Brazil, coronavirus hotspot in Southern Hemisphere Over 100 coronavirus cases in Germany tied to single day of church services — Boris Johnson backs top aide amid reports that he broke U.K. lockdown while exhibiting symptoms.
  4. Public health: Officials are urging Americans to wear masks headed into Memorial Day weekend Report finds "little evidence" coronavirus under control in most statesHurricanes, wildfires, the flu could strain COVID-19 response
  5. Economy: White House economic adviser Kevin Hassett says it's possible the unemployment rate could still be in double digits by November's election — Public employees brace for layoffs.
  6. Federal government: Trump attacks a Columbia University study that suggests earlier lockdown could have saved 36,000 American lives.
  7. What should I do? Hydroxychloroquine questions answeredTraveling, asthma, dishes, disinfectants and being contagiousMasks, lending books and self-isolatingExercise, laundry, what counts as soap — Pets, moving and personal healthAnswers about the virus from Axios expertsWhat to know about social distancingHow to minimize your risk.
  8. Other resources: CDC on how to avoid the virus, what to do if you get it, the right mask to wear.

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Updated 2 hours ago - Politics & Policy

U.S. coronavirus updates

Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Andrew Witherspoon/Axios. This graphic includes "probable deaths" that New York City began reporting on April 14.

The CDC is warning of potentially "aggressive rodent behavior" amid a rise in reports of rat activity in several areas, as the animals search further for food while Americans stay home more during the coronavirus pandemic.

By the numbers: More than 97,700 people have died from COVID-19 and over 1.6 million have tested positive in the U.S. Over 366,700 Americans have recovered and more than 14.1 million tests have been conducted.

World coronavirus updates

Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Axios Visuals

Japan's economy minister outlined plans on Monday to end the nationwide state of emergency as the number of new novel coronavirus cases continues to decline to fewer than 50 a day, per Bloomberg. Japan has reported 16,550 cases and 820 deaths.

By the numbers: Over 5.4 million people have tested positive for the virus as of Monday, and more than 2.1 million have recovered. The U.S. has reported the most cases in the world (over 1.6 million from 13.7 million tests). The U.K. is reporting over 36,800 deaths from the coronavirus — the most fatalities outside the U.S.