His three space shuttle flights included the Discovery mission in October 2000 to expand the International Space Station (ISS), during which he logged more than 13 hours on two space walks. In 2005, McArthur launched from the Baikonur Cosmodrome in Kazakhstan on 30 September aboard a Soyuz spacecraft and docked with the ISS on 3 October 2005 for a six-month stay. McArthur has logged over 224 days in space, including more than 24 hours of space walk time in four space walks. He was assigned to NASA's Johnson Space Center in 1987 as an engineer for the space shuttle, and was selected as an astronaut in 1990.