Bob Behnken is retiring from NASA after a pioneering 22-year career.
Bob Behnken spent a total of 93 days in space over the course of three separate missions. Most of his off-Earth time came on Demo-2, SpaceX's first-ever crewed flight, which sent Behnken and fellow NASA astronaut Doug Hurley to the International Space Station (ISS) for two months in the summer of 2020.
His last day at the agency is today (Nov. 11), NASA officials announced.
"Bob Behnken is a distinguished and talented astronaut, and an effective ambassador for our never-ending mission to explore the cosmos," NASA Administrator Bill Nelson said in a statement on Thursday (Nov. 10).
"Bob and fellow NASA astronaut Doug Hurley launched into history with their impeccable command of NASA and SpaceX's Demo-2 mission and played a pivotal role in helping a new era of commercial space take flight," Nelson added. "Along with the entire NASA family, I appreciate Bob's service to our country and wish him all the best in his next endeavor."
Behnken grew up in St. Ann, Missouri. He earned bachelor's degrees in physics and mechanical engineering from Washington University in St. Louis in 1992, a master's in mechanical engineering from the California Institute of Technology (Caltech) in 1993, and a Ph.D. in the same field from Caltech four years later, according to NASA's Thursday statement.
Behnken joined NASA as an astronaut candidate in July 2000. He first left Earth in 2008, serving as a mission specialist on the STS-123 flight of the space shuttle Endeavour, which delivered Japan's Kibo laboratory and Canada's Dextre robotic arm to the ISS. He performed three spacewalks during the nearly 16-day mission.
Behnken flew to the orbiting lab again in 2010, on Endeavour's two-week-long STS-130 mission. That flight also brought key hardware to the ISS — the Tranquility module and the seven-window cupola, which affords astronauts stunning views of their home planet.
He performed three spacewalks during that 2010 flight and four more over the course of Demo-2, racking up a total of 10 extravehicular activities overall, according to the NASA statement.
Behnken also held the post of NASA's chief astronaut from 2012 to 2015 and was deputy of NASA's Flight Operations Directorate from September 2021 through April 2022.
"Bob served the agency in a vital role as an astronaut and contributed greatly to some of NASA's most important and groundbreaking endeavors," NASA human spaceflight chief Kathy Lueders said in the same statement.
"During his career, he flew missions to help build a world-class science laboratory in space, flew the first commercial crew spacecraft to orbit, and left his mark in the astronaut corps," she added. "All of these contributions to human spaceflight will continue to benefit all of us as we continue to push new boundaries."
Behnken is also a former U.S. Air Force colonel who accrued more than 2,000 flight hours in more than 25 different types of aircraft, according to the NASA statement. He retired from military service in February of this year.
"I am humbled to have had the opportunity to represent our nation as a NASA astronaut, and thankful to have been a part of the team that returned human spaceflight to the United States back in 2020," Behnken said in the same statement. "I am so looking forward to seeing and being amazed by what people of this great agency will accomplish next."
Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook.