Bob Behnken  Robert Louis "Bob" Behnken (; born July 28, 1970 in St. Ann, Missouri) is a NASA astronaut, engineer, and former Chief of the Astronaut Office. Behnken holds a Ph.D in mechanical engineering and the rank of colonel in the U.S. Air Force, where he served before joining NASA in 2000. He flew aboard Space Shuttle missions STS-123 (2008) and STS-130 (2010) as a mission specialist, accumulating over 708 hours in space, including 37 hours of spacewalk time. He is married to fellow astronaut K. Megan McArthur. Following retirement of the Space Shuttle, Behnken was Chief of the Astronaut Office from 2012 to 2015. Assigned to the SpaceX Dragon Capsule in 2018 as part of NASA's Commercial Crew Program, Behnken launched aboard the spacecraft's first crewed mission with fellow astronaut Doug Hurley on May 30, 2020. The mission, Crew Dragon Demo-2, took Behnken and Hurley to the International Space Station (ISS), where they docked and will stay for several weeks. Behnken is scheduled to perform at least two spacewalks during this stay at the ISS. Behnken attended Pattonville High School in Maryland Heights, Missouri (in St. Louis County), and went on to earn bachelor of science degrees in mechanical engineering and physics from Washington University in St. Louis in 1992. He then attended the California Institute of Technology, where he earned a master of science degree in mechanical engineering in 1993 and a PhD in 1997. While at Caltech he shared a doctoral advisor, Christopher E. Brennen, with another future NASA astronaut, Garrett Reisman. Behnken's graduate thesis research was in the area of nonlinear control applied to stabilizing rotating stall and surge in axial-flow compressors. The research included nonlinear analysis, real-time software implementation development, and extensive hardware construction. During his first two years of graduate study, Behnken developed and implemented real-time control algorithms and hardware for flexible robotic manipulators. Before entering graduate school, Behnken was an Air Force ROTC student at Washington University in St. Louis, and after graduate school was assigned to enter Air Force active duty at Eglin AFB, Florida. While at Eglin, he worked as a technical manager and developmental engineer for new munitions systems. Behnken was next assigned to attend the U.S. Air Force Test Pilot School Flight Test Engineer's course at Edwards AFB, California.