Barbara Morgan was selected as the backup candidate for the NASA Teacher in Space Program in 1985 and trained alongside Christa McAuliffe. Morgan was present at the launch of the Space Shuttle Challenger on January 28, 1986. She recently spoke to the BBC about her experience.
Since today is the 30th anniversary of the Challenger disaster (a nice round number), there will be a lot written on the topic. I thought this is an interesting sidebar story that may get overlooked.
Morgan went back to teaching later in 1986 but years later returned to NASA. She flew on the Shuttle Endeavour as a mission specialist on STS-118 in 2007.
You can listen to the interview here. (Warning: video may autoplay.)