This superb photograph of the astronauts wearing their new Mercury spacesuits in front of their Redstone rocket on pad was made by long-time Life photographer Ralph Morse, a man who spent so much time with the Mercury Seven, and with the Gemini and Apollo crews as wel, that John Glenn himself fondly dubbed him “the eighth astronaut.” (Ben Cosgrove, TIME magazine, http://time.com/3879356/mercury-seven-photos-of-nasa-astronauts-in-training/)

The three posed for this photo while anticipating their flights of Mercury Redstone 4, Mercury Atlas 6, and Mercury Redstone 3 , respectively. Glenn was the first American to orbit the Earth, while Shepard was NASA’s first astronaut to go into space. Grissom, who six years later lost his life in the Apollo 204 (also known as Apollo 1) fire at Cape Kennedy, flew a suborbital mission, launched between the flights of Shepard and Glenn.

On February 22, 1961, the Space Task Group announced that Shepard, Glenn, and Grissom had been chosen to begin special training for the Mercury Redstone 3 vault into space. More than a month before the public announcement, Robert Gilruth personally had made his choice, even to the exact flight order of the men selected. (NASA SP-4201, p. 341).