An astronaut who had a "serious medical condition" onboard the International Space Station is safely back on Earth, after the first-ever emergency return space flight. The astronaut and three others returned from a mission in space a month early, making a middle-of-the-night splashdown in the Pacific near San Diego early on Thursday. With assistance from SpaceX , the capsule landed less than 11 hours after the astronauts exited the International Space Station (ISS). Their first stop was a