Morgan logged more than 305 hours in space during shuttle Endeavour's STS-118 mission to the International Space Station in August 2007. She operated the shuttle and station robotic arms to install hardware, inspect the orbiter and support spacewalks. She also taught lessons to schoolchildren on Earth during the mission.
Astronaut Office Chief Steve Lindsey said: "From the Teacher in Space Program to her current position as a fully qualified astronaut, she has set a superb example and been a consistent role model for both teachers and students. She will be missed."
Morgan served as the backup to payload specialist Christa McAuliffe in the Teacher in Space Program. McAuliffe and six other astronauts died in the 1986 Challenger accident.
Morgan was an elementary schoolteacher in McCall, Idaho, before being selected as McAuliffe's backup. She returned to teaching after the accident but in 1998 was selected to join the STS-118 crew in 2002.
Morgan is to assume her new post in August.