Who is the sick astronaut on the ISS? What we know.

NASA will bring four astronauts home from the International Space Station days earlier than planned after one crew member experienced a medical issue that requires further testing. 

In a news conference Thursday evening, agency leaders said the astronaut is "absolutely stable" but needs a full diagnostic workup that can't be done in the lab orbiting 250 miles above the planet. The return from space marks the first controlled medical evacuation from the station in its 25 years of continuous operations...