BY age 33, Barbara Morgan had taught school on a native American reservation in the Rockies and in Ecuador's capital in the Andes. That did not dim her longing for a classroom higher in the sky."I want to go on the space shuttle," Ms Morgan wrote to NASA in 1985, applying to be the first teacher in orbit. "I want to get some stardust on me."
But NASA chose high school teacher Christa McAuliffe instead, with Ms Morgan as her backup.
Ms McAuliffe never made it to orbit -- on January 28, 1986, space shuttle Challenger exploded after liftoff, killing Ms McAuliffe and six crew.
On Wednesday, Ms Morgan, now 55 and the mother of two sons, finally gets her chance, being scheduled to blast off in Endeavour on her first space flight -- and America's first effort since Challenger to put a teacher in orbit.
Originally scheduled for Tuesday, NASA delayed the launch to allow workers time to finish replacing a leaky valve in the shuttle's cabin.
NASA is playing down the flight's symbolism, but Ms Morgan's participation could give the space agency a public relations boost at a time when it has been plagued by problems.
The breakup of Columbia in 2003 killed seven astronauts, while this year NASA has been confronted with an embarrassing astronaut love triangle, a computer meltdown on the International Space Station and a report that unidentified astronauts drank heavily before a launch on two occasions.
"I've definitely thought about Christa and the whole (Challenger) crew," Ms Morgan said. "They've been with us every day of training."