Sixteen years after Christa McAuliffe and six other astronauts died in the Challenger explosion, NASA announced Friday that McAuliffe's fellow teacher and one-time understudy Barbara Morgan will ride aboard a shuttle in 2004.

"NASA has an unfinished mission," Administrator Sean O'Keefe said during a speech at Syracuse University. "It is time for NASA to complete the mission -- to send an educator into space to inspire and teach our young people."

Morgan, 50, is a former third-grade teacher from McCall, Idaho, who now lives in Houston where she has trained and worked at the Johnson Space Center since 1998. She has been named the Educator Mission Specialist.

O'Keefe said Morgan's selection was fitting.

Morgan trained with the Challenger crew and was McAuliffe's backup. She watched from the launch site when the shuttle exploded Jan. 28, 1986, just 73 seconds into its flight.

Since the accident, Morgan has worked with NASA and science organizations "keeping alive Christa McAuliffe's inspiration and the dream of an educator in space program," O'Keefe said.

Morgan's mission will be the first of a series of flights in the new Educator Mission Specialist program. O'Keefe said NASA is developing a partnership with the Education Department and will soon release the details of a national recruitment program for follow-up missions. Each teacher would receive full astronaut training.

"It is vital that we inspire our young people to learn and to teach," O'Keefe said. "I hope that NASA's new direction in this area -- in the person of Barbara Morgan and those who will follow her -- will result in a new crop of young, invigorated educators."

Morgan was unavailable for comment Friday; she was working in Mission Control during the current space shuttle mission.

O'Keefe is a 1978 Syracuse graduate and former professor who took over the space agency in December. He is a former chief financial officer at the Pentagon and a former secretary of the Navy.

Already, O'Keefe has scaled back plans for the international space station, pending a review of the costly project. He has scrubbed missions that would send spacecraft to look at Pluto and Europa, a moon of Jupiter.