Effect Of Spaceflight On Human Body

NASA's Celebrated "Twins Study" Shows What Spaceflight Does To Human Body

Astronaut Scott Kelly made himself a guinea pig for all the people who dream of human journeys to Mars and other destinations in space. In 2015, Kelly rode a rocket into space and spent nearly a year on the International Space Station in low Earth orbit, while his identical twin brother, Mark Kelly, stayed on Earth's surface for NASA's celebrated "...