Astronauts in space can grow up to 3 percent taller during the time spent living in microgravity. That means that a 6-foot-tall (1.8 meters) person could gain as many as 2 inches (5 centimetres) while in orbit. Past studies have shown that when the spine is not exposed to the pull of Earth's gravity, the vertebra can expand and relax, allowing astronauts to actually grow taller. That small gain is short-lived, however. Once the astronauts return to Earth, their height returns to normal after a few months. But still, scientists haven't been able to examine the astronaut's spinal columns when experiencing the effects of microgravity until now.
