Alan Shepard became the first American in Space in May 1961. Alan traveled in the Freedom 7 spacecraft and performed a 15-minute-long mission, having covered a distance of more than 300 miles. At the age of 47 Shepard commanded the Apollo 14 flight. He was the fifth person to walk on the surface of our natural satellite, but the first one to play golf there!

Yuri Gagarin of the Soviet Union, beat Shepard and became the first person to enter space, and the first to orbit the Earth on the 12th of April, 1961.

John Glenn's space flight in February 1962 made him the 3rd American, and 5th person to be in space. However, he gained fame as the first American to complete an orbit of the Earth. This fame make many people believe that Glenn was the first American in Space.

Neil Armstrong's first flight was in 1966 as part of the Mercury program. He gained international fame as the commander of Apollo 11, and the first person to walk on the Moon.

More Info: en.wikipedia.org