Gemini IV made history on June 3, 1965, when astronaut Edward White became the first American to walk in space. The 23-minute extravehicular activity (EVA) was a defining moment of the Space Race and produced one of the most iconic photographs in the history of spaceflight — White floating above the brilliant blue Earth, connected to his spacecraft by a golden tether.

The mission was commanded by James McDivitt, with Ed White as Pilot. Their first task after reaching orbit was an attempt to station-keep with the spent Titan II second stage. McDivitt chased the tumbling rocket body for several orbits, burning precious fuel, but could never close the distance. This became one of the early hard lessons in orbital mechanics — what works intuitively in an atmosphere does not work in orbit, where thrusting toward a target can actually push you away.

The main event came during the third orbit. White opened the hatch and floated into the void, propelling himself with a Hand-Held Maneuvering Unit (HHMU), nicknamed the “zip gun.” The small gas gun worked perfectly, allowing White to maneuver around the spacecraft with remarkable ease. He was having so much fun that when Mission Control ordered him back inside, he famously replied, “I’m doing great — it’s the saddest moment of my life.” McDivitt had to coax him with the now-legendary call: “Come in, Ed.”

Gemini IV was also the first mission controlled from the new Mission Control Center in Houston, Texas, replacing the Mercury Control Center at Cape Canaveral. The crew spent four days in orbit conducting 11 experiments before splashing down in the Atlantic Ocean on June 7, recovered by the USS Wasp. Tragically, Ed White would lose his life less than two years later in the Apollo 1 fire.