They would monitor and adjust the cabin environment. They would operate the communications system. They would make physiological, astronomical, and meteorological observations that could not be made by instruments. Most important, they would be able to operate the reaction controls in space and be capable of initiating descent from orbit. This was the key part, that the astronaut could take over control of the spacecraft itself.
The chosen seven had shown emotional maturity, engineering, flight experience and motivation. Eighteen others were unreservedly recommended.
On 27 April 1959 they began work at Langley Air Force Base. NASA was considering 10 flights carrying chimpanzees but this changed on 12 April 1961. The Soviets made the first manned flight. Shepard followed on 5 May 1961. On 25 May President Kennedy presented his vision to Congress.
A couple of weeks later, Gilruth and Webb were aboard one of NASA’s R4Ds when over the radio the president was addressing Congress, pledging NASA to a lunar expedition. Gilruth was “aghast.” He looked at Webb, who knew all about it. In his special message to Congress, delivered on May 25, 1961, President Kennedy set out his vision on a number of “urgent national needs,” one of them the conquest of space. In a resonant call to arms, the president asked the nation to “commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth.” No other space project, Kennedy declared, would be “more impressive to mankind, or more important for the long-range exploration of space.”