Scott Kelly is back in the United States after spending 340 days in space, aboard the International Space Station. <br />It is the longest a US astronaut has ever spent in space on a single trip. <br />Along with his crewmates he was involved in more than 450 experiments while on board. <br />Life in microgravity meant his height increased by 3.8cm but he has since returned to his normal size back on Earth.
