Gemini 4

Gemini 4 was the second crewed spaceflight of NASA's Project Gemini, launched on June 3, 1965. It was a four-day mission crewed by James McDivitt and Edward White. The mission's most significant highlight was the first extravehicular activity (EVA), or spacewalk, by an American, performed by Ed White. Floating outside the spacecraft for 23 minutes, White demonstrated that humans could work and maneuver in the vacuum of space. The mission also attempted the first space rendezvous with the spacecraft's spent Titan II upper stage, though this proved more difficult than expected. Gemini 4's success provided vital data on long-duration flight and EVA operations, both of which were essential for the upcoming Apollo lunar missions.