NASA Findings Suggest Health Concerns for Astronauts on Long-Duration Space Missions
published during a waxing gibbous moon.

ISS missions usually last no longer than six months, but from March 2015 to March 2016, two astronauts—American Scott Kelly and Russian Mikhail Kornienko—extended their stay in space for the One-Year Mission, an investigation aimed at uncovering the medical, physiological, and biomedical challenges of long-duration space missions. NASA recently released the preliminary findings, which suggest that long periods of time in microgravity affect fine motor skills, posture, vision, microbiomes, and genes. The results also underscore the need for further testing before astronauts make the journey to Mars.

The Functional Task Test measured the astronauts’ ability to perform various tasks and maneuvers necessary upon arrival on Mars. Both Kelly and Kornienko demonstrated difficulty completing tasks that required “postural control and stability and muscle dexterity.” This finding isn’t too surprising, as a lack of gravity decreases muscle mass, which takes a particular toll on astronauts’ core muscles.

health concerns

NASA Astronaut Scott Kelly performs the Fine Motor Skills Test as part of his One-Year Mission. This task tests Kelly’s ability to use his fine motor skills – pointing, dragging, shape tracing, and pinch-rotate – on an Apple iPad after extended time in space. Credit: NASA

Credit: NASA

Kelly and Kornienko’s fine motor skills were also negatively impacted. Tests requiring the astronauts to point, drag, trace shapes, and pinch-rotate images on an iPad revealed diminished accuracy and response times. While not surprising, especially given that some of us struggle to perform these actions right here on Earth, it’s crucial that astronauts retain fine motor skills to be able to use computers and make repairs to various systems on Mars.

Results were split about the Visual Impairment and Intracranial Pressure test. We now know a bit more about why astronauts tend to have vision problems after living in space; interestingly, one of the two astronauts showed signs of visual impairment, while the other one didn’t. Researchers aren’t sure why this is but speculate it might be related to the astronauts’ cardiovascular health.

One bit of good news is that Kelly and Kornienko enjoyed an hour more sleep per night on average than astronauts who spent six months on the ISS between 2004-2011. They may have gotten used to living and sleeping in space, or perhaps their schedules were more forgiving.  Whatever the reason, the two astronauts slept an average of 7 hours a night.

health concerns

Mark and Scott Kelly. Credit: NASA

Perhaps the most interesting and enlightening aspect of the study is that Scott’s twin brother, Mark, who is also an astronaut, served as a “control” by remaining on Earth for the year. NASA researchers are comparing  Mark and Scott’s data and noting the differences in the two men between March 2015 and March 2016.

Some of the preliminary results from this “Twins Study” showed that Scott’s DNA experienced less chemical modification during his time on the ISS, and the two men had roughly 200,000 different RNA molecules by the end. More testing needs to be conducted to identify specifics, but the finding supports the theory that time in space changes one’s DNA. Researchers are particularly interested in determining whether there’s a “space gene” that might kick in when someone leaves Earth.

One of the most surprising findings is that Scott’s telomeres—protective chromosomal sequences that shorten with age—actually lengthened while he was in space (they shrank again upon his return to Earth). Researchers aren’t sure why this is, but believe it might be a result of Scott’s exercise and dietary regimens. Scott’s gut bacteria changed in space too.

health concerns

Astronaut Omics illustration. Credit: NASA

Judging by these early findings, it’s clear that spending a prolonged time in space isn’t great for the human body. NASA will continue to release more reports from the study later this year and plans to continue designing studies about the effects of long-duration spaceflight with the goal of increasing astronauts’ ability to maintain health and well-being on their future cosmic journeys.