It exploded when the flame on the engine ran out of energy and flamed the Challenger.
1986
The Space Shuttle Challenger exploded on January 28, 1986.
The Challenger space shuttle exploded on January 28, 1986, 73 seconds after liftoff.
The space shuttle Challenger exploded on January 28, 1986, which was a Tuesday.
The space shuttle Challenger exploded on lift-off on January 28, 1986.