Gemini 8 docking
IMAGE ABOVE: Neil Armstrong pilots the first docking in space, joining up Gemini 8 with an unmanned Agena.
While the Soviet Voskhod program had only two (spectacular!) crewed missions, the American Gemini program racked up success after success to develop the skills needed to go to the moon.

As determined by NASA, the needed skills included:

1. Long duration flight—a round trip to the moon would take more than a week
2. Extra Vehicular Activity (EVA)—astronauts would need to exit the spacecraft to walk on the moon
3. Rendezvous and docking—precision movement in space so that the command ship and lunar lander could join up and return to Earth

A few months after Alexi Leonov’s historic first space walk, astronaut Ed White performed America’s first EVA aboard Gemini 4.

Ed White performs the first American space walk
IMAGE ABOVE: Ed White performs the first American space walk during the flight of Gemini 8.
Gemini 5 achieved he minimum duration for a lunar flight (at least a non-landing trip to the moon) with its 8 day mission.

Gemini 7 bettered that record with a 2 week flight. During that mission, Gemini 7 was joined by Gemini 6 which succeeded in performing a rendezvous with Gemini 7.

Astronaut Neil Armstrong performed the first docking of two spacecraft when he piloted Gemini 8 to link up with an unmanned target in orbit, called Agena.
Doing actual work in space proved to be tricky and Gemini saw several harrowing space walks before Buzz Aldrin worked out the kinks in his successful EVA aboard the final flight of the program, Gemini 12.