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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

16 mins ago - World

Report: "Clear evidence" China is committing genocide against Uyghurs

The scene in 2019 of a site believed to be a re-education camp where mostly Muslim ethnic minorities are detained, north of Kashgar in China's northwestern Xinjiang region. Photo: Greg Baker/AFP via Getty Images

Chinese authorities have breached "each and every act prohibited" under the UN Genocide Convention over the treatment of Uyghurs and other Muslim minorities in China's Xinjiang province, an independent report published Tuesday alleges.

Why it matters: D.C. think-tank the Newlines Institute for Strategy and Policy, which released the report, said in a statement the conclusions by dozens of experts in war crimes, human rights and international law are "clear and convincing": The ruling Chinese Communist Party bears responsibility.

Updated 2 hours ago - Technology

Twitter sues Texas AG Ken Paxton

Texas Attorney General Ken Paxton at February's Conservative Political Action Conference in Orlando, Florida. Photo: Joe Raedle/Getty Images

Twitter on Monday filed a lawsuit against Texas Attorney General Ken Paxton (R), saying that his office launched an investigation into the social media giant because it banned former President Trump from its platform.

Driving the news: Twitter is seeking to halt an investigation launched by Paxton into moderation practices by Big Tech firms including Twitter for what he called "the seemingly coordinated de-platforming of the President," days after they banned him following the Jan. 6 Capitol insurrection.

7 hours ago - Politics & Policy

Senate retirements could attract GOP troublemakers

Sen. Roy Blunt (R-Mo.). Photo: Jim Lo Scalzo/EPA/Bloomberg via Getty Images

Sen. Roy Blunt's retirement highlights the twin challenge facing Senate Republicans: finding good replacement candidates and avoiding a pathway for potential troublemakers to join their ranks.

Why it matters: While the midterm elections are supposed to be a boon to the party out of power, the recent run of retirements — which may not be over — is upending that assumption for the GOP in 2022.