Science

8 weird things that happen to your body if you live in space for a year like Scott Kelly

Read in app
scott kelly astronaut space station nasa
Former NASA astronaut Scott Kelly.  Bill Ingalls/NASA

In the name of science, former NASA astronaut Scott Kelly shoved himself into the top of a rocket, accelerated to 17,500 mph, and fell around Earth for 340 days — nearly an entire year.

The lack of gravity, radiation exposure, Kelly's diet, and other facts of life in orbit affected his body in significant ways — including, as NASA is learning now, even perhaps his genetic blueprint.

The Twin Study, which is still in progress, uses Scott Kelly's identical twin brother and fellow former astronaut, Mark Kelly, to unmask the subtle but important effects of long-duration space travel on the human body.

Here are eight biological oddities that researchers have found happen to your body if you're in space for a year.

Your face looks different.

Your bone density can change.

Your body fluids shift.

Your sight could change.

Your muscles can atrophy.

You'll be sleepy.

Your cancer risk increases.

You get taller — until you get back to Earth.

Read next

Skye was the Design Director for Business Insider and Insider. She led the Graphics and Photo teams in producing all graphics, data visualizations, story art, photography, and special projects for the newsroom.
Dave Mosher reported news and features stories about science and technology for Insider, with human and robotic spaceflight as the primary focus of his multimedia storytelling. Mosher joined Insider in April 2015 as a deputy editor to help launch Tech Insider and manage its science desk. He left the company in February 2021. Prior to being an Insider, Mosher directed Popular Science's website, was a Wired contributor, and worked for or with Scientific American, Popular Mechanics, Discover, Space.com, National Geographic NewsDiscovery Channel, Nature, Science, and other media outlets.
Rebecca was an Executive Editor for Business Insider's news division, overseeing the Science, Speed news, Weekend news, LA news, Visual Features, and Voices of Color desks. She worked across teams to assign, coordinate, and edit breaking news, explainers, features, analysis, and investigations. She also developed guides, trainings, and coaching opportunities for the newsroom to get better every day.Rebecca started as a reporter on Tech Insider's science section in 2015, covering everything from solar energy and rocket launches to Zika, before moving to the news team during the summer of 2016 at the height of the presidential election and then running weekend coverage for 2 years. She's previously worked with the Politics, Military & Defense, and Video teams, and served as an editorial liaison with the product team that powers the CMS.She received her Master's degree from the Science, Health and Environmental Reporting Program at New York University, as well as a BS in Biology and a BA in Journalism from the University of Minnesota. Rebecca has also written for Popular ScienceScientific AmericanScienceline, the Minneapolis Star Tribune, and the Minnesota Daily.ExpertiseBreaking news, legal analysis, criminal justice, police misconduct, public health, abortion, space, energy, visual features, extreme weather, White House history, voting rights, executive actionsPopular articlesJust don't call it 'climate change': What Republicans in Dallas can teach us about saving the planetWhat Buzz Aldrin was thinking when he left the moonHow the 25th Amendment works to remove a sitting presidentHurricane categories tell only part of the storyTRUMP'S FIRST 100 DAYS: Here's how they compare with Obama's, Bush's, and Clinton's