Four astronauts are set to begin their return journey from the International Space Station (ISS) to Earth after their mission was cut short due to a "medical concern" with a crew member. NASA said it will bring home the crew "earlier than originally planned" depending on weather conditions, marking the first time it has carried out a medical evacuation from the space station. Officials have not revealed details of the medical issue due to patient privacy, but said the crew member was "stable".