Reagan's speech from January 28, 1986 was a mourn speech after the explosion of the Space Shuttle Challenger, the first in-flight explosion in space program history. Ending the speech with the quote from "High Flight" was a way of connecting both tragedies, all of the deaths of WW2 and these deaths in the Shuttle, and a way of saying that the nation and the space program will continue despite the tragedy, just as United States continued WW2 until tyranny in Europe was defeated.
