“This is the greatest experience, it’s just tremendous.” On June 3, 1965, NASA Astronaut Edward H. White II became the first American to venture outside his spacecraft for what is officially known as an extravehicular activity, or EVA. The world has come to know it as a spacewalk. While floating in space, White carried a Hand-Held Self-Maneuvering Unit (HHSMU) that gave him control over his movements in space. He carried a camera mounted on the HHSMU for taking pictures of the sky, Earth, and the GT-4 spacecraft. White also wore an emergency oxygen chest pack and was secured to the spacecraft by a 25-feet (7.6 meters) umbilical line and a 23-feet (7 meters) tether line. Gemini IV was the second crewed mission of the Gemini series. Ed White and James A. McDivitt successfully completed the 4-day flight between June 3 and June 7, 1965. Learning how to conduct a spacewalk helped pave the way for Apollo explorers to walk on the Moon. Image description: Astronaut Ed White floats in ...