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A Mission to Mars Could Cause Serious Brain Damage

Radiation exposure from long-haul space travel could lead to dementia, anxiety, and poor decision-making, according to study in mice and rats

2 min read
A cartoon astronaut floating above a red-orange Mars-like background
Illustration: iStockphoto

Space is a dangerous place. A new report shows just how dangerous it could be to human brains. Radiation exposure from a Mars missions could cook brain cells, causing chronic dementia and memory loss, and leaving astronauts with debilitating anxiety levels, the study has found. This could throw off their thinking and judgment, impairing decision-making and multi-tasking.

The results, published in Scientific Reports, are based on experiments in rodents. Radiation oncologist Charles Limoli and his colleagues at the University of California Irvine bombarded mice and rats with low-doses of ionized oxygen or titanium. These charged particles have similar energies to those of cosmic rays that can pass right through the shielding on spacecraft. The dosage levels that the researchers used were similar to what astronauts would be exposed to during a three-year round-trip mission to Mars, Limoli says.

The researchers looked at the prefrontal cortex, the brain region linked to decision-making, executive function, and long-term memory. They saw significant damage and inflammation in the brains of exposed animals as long as six months after the exposure.

The radiation damaged the tiny branches on neurons that help transmit electric signals to the nerve cell body. This led to a loss in learning and memory. The exposed animals performed poorly on behavioral tests that measure intelligence, and they showed higher, constant anxiety levels.

“Our tests ask animal to recognize and respond to novelty,” Limoli says. “Smart animals recognize novelty. The affected animals show stress and don’t explore.”

Astronaut Scott Kelly’s 340-day trip aboard the International Space Station was part of NASA’s plan to study the effects of long-term spaceflight on the human body. However, going to Mars is a whole different beast than a trip to the moon or the ISS. NASA has been researching the risks of long-haul missions to the red planet and beyond. Limoli’s US $9 million project to investigate how cosmic radiation affects astronauts’ cognition is part of NASA’s Human Research Program.

A six-week study done by the group last year showed similar results. The latest findings, 12 and 24 weeks of measurement, show the long-term nature of brain damage from space travel. “What’s most surprising is how persistent some of the changes to the structure of neurons are,” Limoli says. He adds that his group has unpublished data showing that these effects last for a year.

While the results might not translate directly to humans, he says that it definitely implies that deep space travel could carry huge risks for astronauts. “Space is an inexact science.”

NASA is already investigating ways to mitigate radiation risks. These include thicker shielding, new radiation-blocking materials, protective suits, magnetic fields to recreate Earth’s natural shield. Limoli, meanwhile, is developing drugs that could protect the brain’s circuitry. 

This story was corrected on 10 October.

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Economics Drives Ray-Gun Resurgence

Laser weapons, cheaper by the shot, should work well against drones and cruise missiles

4 min read
In an artist’s rendering, a truck is shown with five sets of wheels—two sets for the cab, the rest for the trailer—and a box on the top of the trailer, from which a red ray is projected on an angle, upward, ending in the silhouette of an airplane, which is being destroyed

Lockheed Martin's laser packs up to 300 kilowatts—enough to fry a drone or a plane.

Lockheed Martin

The technical challenge of missile defense has been compared with that of hitting a bullet with a bullet. Then there is the still tougher economic challenge of using an expensive interceptor to kill a cheaper target—like hitting a lead bullet with a golden one.

Maybe trouble and money could be saved by shooting down such targets with a laser. Once the system was designed, built, and paid for, the cost per shot would be low. Such considerations led planners at the Pentagon to seek a solution from Lockheed Martin, which has just delivered a 300-kilowatt laser to the U.S. Army. The new weapon combines the output of a large bundle of fiber lasers of varying frequencies to form a single beam of white light. This laser has been undergoing tests in the lab, and it should see its first field trials sometime in 2023. General Atomics, a military contractor in San Diego, is also developing a laser of this power for the Army based on what’s known as the distributed-gain design, which has a single aperture.

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