Ellen Stofan is a planetary geologist who 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 (Harper Collins, 2006) and The Complete Idiots Guide to NASA (Alpha, 2002) as well as a contributing writer to Smithsonian Air and Space magazine.