NASA astronaut Mike Fincke, whose medical issue forced the early termination of a mission and evacuation from the International Space Station, still hasn't revealed what caused his illness. Fincce, who had previously served in space four times, was eating dinner and preparing for a space walk when he suddenly felt dizzied and unable to speak. His crewmates alerted flight surgeons back on Earth and he felt fine after the episode, which lasted about 20 minutes. Despite not having a heart attack, doctors are still trying to determine what caused this illness.