Living in space is not the same as living on Earth. In space, astronauts’ bodies change. On Earth, our lower body and legs carry our weight. This helps keep our bones and muscles strong. In space, astronauts float. They do not use their legs much. Their lower backs begin to lose strength. Their leg muscles do too. The bones begin to get weak and thin. This is very bad for astronauts’ bodies. They must exercise in space every day. Hygiene….