CARL E. WALZ is a Colonel in the U.S. Air Force (USAF; retired) and a former NASA astronaut. From 1979 to 1982, he was responsible for analysis of radioactive samples from the Atomic Energy Detection System at McClellan Air Force Base, California. The subsequent year was spent in study as a Flight Test Engineer at the USAF Test Pilot School, Edwards Air Force Base, California. Col. Walz later served as a flight test engineer to the F-16 Combined Test Force at Edwards Air Force Base, where he worked on a variety of F-16C airframe avionics and armament development program and as a flight test manager at Detachment 3, Air Force Flight Test Center. He is a veteran of four space flights and one International Space Station expedition and has logged a total of 231 days in space. In addition to his flights, he served in a variety of technical and management positions within the Astronaut Office at Johnson Space Center. Dr. Walz most recently served as director for the Advanced Capabilities Division in the Exploration Systems Mission Directorate at NASA Headquarters. In the division, he played a key role in developing technologies that will lead to greater capabilities in robotic and human exploration of the solar system. He oversaw work in many fields, including nuclear power and propulsion, human adaptation to spaceflight, and lunar exploration. Many of these programs will help humans return to the moon and develop a sustained presence there. He retired from NASA in 2008 to pursue interests in the private sector. He has received numerous awards and honors, including four NASA Space Flight Medals, a NASA Distinguished Service Medal, and the NASA Exceptional Service Medal.