Upon researching about astronaut Scott Kelly, who spent a year in space, I learned that he faced some problems. One of them was swelling on his legs. The reason why his legs swelled was because of fluid in his body that was not circulating. It was building up inside his legs. So my mom and I came up with an idea and the idea was a compression sock. Compression socks work by compressing the leg causing the inside of the leg to push fluid up and back into proper circulation. Compression socks are made of nylon. The reason why astronauts need compression socks is because then they would not have to worry about their legs and the fluid building up like what happened to Scott Kelly.