NASA's Apollo 11 mission sent three astronauts to the moon exactly 50 years ago, in July 1969. Two of them landed on the moon's surface and they all returned home safely.
But NASA knew the mission was very risky, so the White House prepared remarks in case the astronauts died.
President Nixon's speechwriter, William Safire, drafted the backup speech, titled "In Event of Moon Disaster," which was publicly released 30 years later.
In the years since Apollo 11, we've learned about ways the astronauts could have died several times during the mission.
Apollo 11 astronauts planted a flag on the moon on July 20, 1960