Space Missions Change the Way Astronauts Think, but It's Probably Not a Problem

On space missions, astronauts often have to make independent decisions quickly. The wrong move at the wrong moment could have disastrous consequences, leaving the crew adrift and in danger, far from home. So far, our space missions have stayed relatively close to home. Even the ill-fated crew of Apollo 13 had help from Earth in the form of relatively real-time communication with ground control.

As astronauts travel farther into space, toward Mars and beyond, they’ll have the added problem of increased communication delays. Depending on where Mars and Earth are in their orbits, the communication transit times can be between 4 and 24 minutes, each way. If something goes wrong on Mars, as it almost certainly will, the crew may not have 20 minutes to wait before making a decision. Ensuring that their cognitive performance remains strong throughout the mission will be critical to the success of any deep space journeys.

We already know that exposure to space has negative effects on the body. Astronauts experience everything from difficulty with vision to muscle loss, bone loss, and kidney dysfunction. The effects on the brain, however, are less well understood, but just as important to the success of the mission and the long-term health of the crew.

Hoping to close that knowledge gap, a recent study published in Frontiers in Physiology assessed the cognitive performance of 25 NASA astronauts before, during and after their time aboard the International Space Station (ISS). The study found some changes in working memory, processing speed, and sustained attention, but no group-level decline in cognition.

How being in space changes the way astronauts think

Apollo 12 astronaut Alan L. Bean holding a sample. Credit: NASA

Deep space missions are an inherently risky business even when everything goes right. When things go wrong, as they inevitably do, it’s critical that the minds of astronauts are sharp enough to meet the challenge. It’s a problem illustrated nicely in SYFY’s The Ark, which follows the crew of the Ark One, humanity’s first interstellar colony ship. They’re on a mission that’s years long, but ostensibly cozy. They’ve got sleeping pods and artificial gravity, but it all goes sideways when the ship is damaged and half the crew (including the entire leadership cabin) vanishes into the abyss. The surviving crew has to make quick decisions to save their own lives and try to right the ship in the vast emptiness between stars.

Back on Earth and in the real world, scientists are hoping to learn about the limitations of human cognition in space to better prepare for the missions of the future. Astronauts were given a battery of 10 tests once before flight, once during the early part of a 6-month mission, once toward the end of the mission, and twice within 30 days of landing. Overall, astronauts were just as accurate at performing tasks in space, but they took a little longer to complete tasks measuring processing speed, working memory, and sustained attention, when compared with their terrestrial baseline results.

Risk-taking propensity was also impacted during the early phase of the mission, but subsided later. Some of the other deficits persisted into post-flight and hadn’t returned to normal after 30 days back on Earth. There was some variability among the sample of astronauts, which demonstrates that some individuals may be impacted more than others, but there were no significant group-level effects. Importantly, there was also no correlation with the amount of sleep or rating of alertness reported by astronauts.

It’s unclear at present if the minor cognitive deficits detected by the study are the result of exposure to space (microgravity, radiation, isolation) or the consequence of a high-stress environment. Separate terrestrial studies have shown that a stressful environment impacts cognitive performance, and there are few working environments more stressful than space. Regardless, it may be impossible to totally mitigate the effects. Instead, the real value of this study might be in shining a spotlight on when astronaut cognition might be compromised and designing missions around those human limitations.

Watch The Ark, streaming now on Peacock.