Endurance: A Year in Space, a Lifetime of Discovery is a 2017 memoir by American astronaut Scott Kelly and Margaret Lazarus Dean. The book details Kelly's life, as well as that of his twin brother Mark, as they became naval aviators and test pilots, and were both selected for NASA Astronaut Group 16. Kelly recounts his four spaceflights, with an emphasis on the ISS year long mission, in which he participated.