A ceremony in Titusville, Florida, honored the 17 astronauts lost in NASA's Apollo 1, Challenger and Columbia tragedies.

Forty years ago, the NASA space shuttle Challenger exploded 73 seconds after liftoff, killing all 7 crew members.

“Having the first educator, Christa McAuliffe, on that flight, there was a lot of student interest because there were her lessons that she was going to do up in space that the kids could follow along ...