"People keep saying, '20 years, 20 years!' but it really seems like just yesterday," Morgan said.
It was 22 years ago on July 19, 1985, when then-Vice President George H.W. Bush called Morgan's name at a White House ceremony. Morgan was the runner-up in the contest to be the first teacher in space. Christa McAuliffe was the winner.
As McAuliffe's backup, Morgan trained with her and the Challenger shuttle crew every day for six months, playing in zero gravity, planning lessons for the space flight.
On Jan. 28, 1986, just 73 seconds into flight, and with the entire nation watching, the Challenger exploded and fell into the sea. Morgan lost seven good friends that day.
How did McAuliffe's death change Morgan?
"It makes you really sad of course, just like it did for everybody," Morgan said. "Crista was and is and always will be a great representative of the teaching profession."
After the Challenger disaster, NASA decided that civilians — including teachers — didn't belong on the shuttle.
Morgan would just have to become a full-fledged astronaut. It took 12 years, but on the same day John Glenn was named to a shuttle flight, NASA welcomed Morgan into the class of 1998.
Then, another tragedy: The shuttle Columbia — the orbiter Morgan was assigned to ride on her first flight into space — disintegrated on its way back to earth. Morgan was devastated, but undeterred.
She hung in there all those years.
"So did everybody else, and it's not hanging in there. Teachers don't 'hang in there.' Teachers have persistence and patience," Morgan said.
When the Endeavor takes off from the launch pad, Morgan will be in the same position — center seat, lower deck — as McAuliffe was more than two decades ago.
"I actually haven't thought about that, but we all keep the Challenger crew right here," she said, pointing to her heart.
She'll take with her the memory of those astronauts in her heart – and maybe a few butterflies in her stomach as well.