William Ketchum is an Associate Fellow of the American Institute of Aeronautics and Astronautics. He holds a Bachelor of Science degree in Aeronautical Engineering, and a Master of Science degree in Aerospace Systems Management from the University of Southern California. He started his Aerospace career in 1956 at Edwards Air Force Base in Flight Test Engineering. He then worked for General Dynamics Space Systems Division specializing in cryogenic liquid propellant rocket propulsion systems, developing the Atlas and Centaur space launch vehicles. He participated in designing the Fully Reusable Space Shuttle, Space-Based Orbit Transfer Vehicles, and Nuclear-Thermal rockets for human interplanetary missions. His military experience was in the U.S. Army Missile Command at Redstone Arsenal testing the solid propellant Nike-Zeus Missile Defense System. His work is in Astronautics and Astrodynamics. He is a consultant for the next generation of Space Launch Systems, and he is developing a small reusable personal spaceplane. He has written many technical reports and papers and lectured on the history of the space program at schools and public events nationwide. He lives in San Diego, California.