Final answer:
The American space program that sent pairs of astronauts into space was known as Gemini.
Step-by-step explanation:
The American program that put pairs of men into space was called Gemini. The Gemini program followed the earlier Mercury program, which included solo flights such as astronaut Alan Shepard's historic journey and John Glenn's orbital flight. The goal of Gemini was to test space travel techniques in preparation for the Apollo missions, which ultimately landed men on the Moon. Gemini missions included activities such as spacewalks, rendezvous, and docking with other spacecraft—all critical skills for the moon landing endeavor. It was part of the larger U.S. space program known as Project Gemini and operated between 1961 and 1966.