NASA said that veteran U.S. astronaut James Reilly, who flew on three space shuttle missions to two space stations, has left NASA to accept a position in the private sector.

"Jim Reilly performed superbly as an astronaut over the course of his career at NASA," Astronaut Office Chief Steve Lindsey said. "His technical, operational and people skills contributed directly to the success of the space shuttle and International Space Station programs. He was a key leader in the Astronaut Office and will be missed."

Reilly clocked more than 853 hours in space, with his five spacewalks totaling more than 31 hours.

Selected as an astronaut in 1994, Reilly first flew in January 1998 aboard shuttle Endeavour's STS-89 mission, the eighth shuttle mission to visit the Russian space station Mir. He next flew in 2001 aboard space shuttle Atlantis during STS-104, performing three spacewalks to install the joint airlock on the International Space Station.

Reilly again flew on Atlantis in 2007 on STS-117, performing two spacewalks for construction and repair of the International Space Station.