First U.S. Spacewalk, By Astronaut Ed White, Occurred 48 Years Ago (VIDEO)

Which U.S. astronaut made the first American spacewalk?

It was Edward H. White II (1930-1967). He opened the hatch of his Gemini 4 capsule on June 3, 1965 -- 48 years ago today -- and stepped out into the void.

The 23-minute spacewalk -- or extravehicular activity (EVA) in NASA parlance -- started as the capsule was over the Pacific Ocean and ended above the Gulf of Mexico.

White used jets of oxygen from a hand-held "gun" to propel himself to the end of the 8-meter tether that linked him to the capsule. (You can see the gun in White's right hand in the video above.) When the oxygen ran out, he resorted to twisting his body and pulling on the tether.

White's pioneering EVA was a source of pride for Americans. But White -- a native of San Antonio, Texas -- wasn't the first man to walk in space. That distinction belongs to Soviet cosmonaut Alexei Leonov, who stepped from his Voskhod 2 capsule while orbiting the earth on March 18, 1965.

White died less than two years later, while training for the Apollo 1 mission.