These were the first astronauts chosen to fly into space for the USA, they were called the Astronaut Group 1, but are more commonly known as the Mercury Seven. Some went on to fly further missions, but all achieved greatness by being the first Americans to fly into space and safely return to earth.
It was during this time that John F. Kennedy made his "we choose to go the moon" speech which challenged the US people to support the race to the moon, the rest of which is history.