Ellen Stofan, a planetary geologist, has conducted research on the geology of volcanic and tectonic features on Venus, Mars, Titan, and Earth. She is currently a Senior Research Scientist of Proxemy Research and an Honorary Professor of Earth Sciences at University College London.
Tom Jones is a scientist, author, pilot, and former NASA astronaut. He led three space walks to install the centerpiece of the International Space Station. He is the author of Sky Walking: An Astronaut's Memoir and The Complete Idiots Guide to NASA, and is a contributing writer to Smithsonian Air and Space magazine.