For the first time in human existence, man finally broke the bounds of the earth when the three Apollo 8 astronauts took man's first trip to the moon. This flight was initially planned as another earth orbiting checkout of the Apollo hardware, but rumors that the Soviets were plotting to beat us into orbit around the moon caused a little last-minute change in plans.
This was the first human spaceflight atop the wondrous Saturn V launch vehicle, which had flown only twice before. There could be no thought of a lunar landing; like Apollo 7, no Lunar Module had been launched with them.
The booster worked flawlessly, as did the Service Propulsion Module. Who can forget Christmas Eve, when the astronauts passed behind the moon, and fired their engines while outside communications range? The whole nation, the whole world, sat and waited on the edge of our seats, waiting for the craft to come out from behind the moon. Did the engines fire properly? Could they come home, or would they remain, forever trapped in the icy cold of space?
It all worked, and Apollo 8 proved at last that our horizons are truly limitless. Man had, at last, seen the Earth rise above the horizon of another world, and brought back the pictures to prove it!