Barbara Morgan applied for the position filled for which Christa McAuliffe was eventually chosen. Morgan remained with the U.S. space problems as McAuliffe's backup for the planned expedition of the Challenger. That space shuttle exploded shortly after liftoff Jan. 28, 1986, with McAuliffe and six others on board.
Morgan is to be on board Tuesday on space shuttle Endeavour, the space shuttle built to replace the Challenger, when it is launched on a mission to the International Space Station.
"It has taken a long time for NASA to fly another educator in space," said National Aeronautics and Space Administration spokeswoman Sonja Alexander. She blamed the delay on shuttle accidents and management changes at the space agency.
"I've definitely thought about Christa and the whole (Challenger) crew," Morgan said. "They've been with us every day of training."