ROD PYLE is an author, journalist, and editor-in-chief of Ad Astra magazine. He has written extensively for NASA's Jet Propulsion Laboratory, including their annual Technology Highlights book, and has written 20 nonfiction books on space history, exploration, and development, as well as 20th-century history. GERRY GRIFFIN is an American aeronautical engineer and former NASA official, who served as a flight director during the Apollo program and director of Johnson Space Center.