On March 18, 1965, cosmonaut Alexei Leonov became the first person ever exit a space vehicle and take a so-called “spacewalk.”
The Voskhod (“Sunrise”) was a modifed Vostok capsule such as was used by Yuri Gagarin. The 16.4-foot (5 meters) Voskhod carried two or three cosmonauts for up to 14 days in Earth orbit.
Commander Pavel Belyayev remained in the pressurized cabin, wearing a spacesuit identical to Leonov’s in case a rescue was needed.
After 12 minutes of spacewalking, Leonov discovered that his spacesuit had over-inflated so much that he could not return through the hatch. As a desperate last resort, Leonov opened a valve to let the pressure out of the suit. When the suit deflated enough, Leonov was able to squeeze through the hatch.
The first American spacewalk followed just a few months later, on June 3, 1965, when NASA astronaut Ed White floated outside his Gemini 4 space capsule for a 23 minute excursion while crewmate James McDevitt remained inside.
White used a prototype gas gun to maneuver around outside the capsule, and remained connected to the ship via an umbilical-cord like tether.