Scott Joseph Kelly is an engineer, retired American astronaut, and a retired U.S. Navy Captain. A veteran of four space flights, Kelly commanded the International Space Station on Expeditions 26, 45, and 46.
Clive Adrian Stafford Smith OBE is a British attorney who specialises in the areas of civil rights and working against the death penalty in the United States of America.
Carl Zimmer is a popular science writer and blogger who has specialized in the topics of evolution and parasites. He has authored many books and contributes science essays to publications such as The New York Times, Discover, and National Geographic.