On June 3, 1965, astronaut Major Edward H. White II became the first American to walk in space when he stepped out of the space capsule, Gemini 4. He was tethered by a 25-foot cord and stayed outside the capsule for 20 minutes. The Gemini missions proved very helpful to our space knowledge. The extended duration of the trips provided valuable information about the biological effects of longer-term space travel, and astronauts perfected docking maneuvers with other orbiting vehicles.
