Gemini 4
First American spacewalk and first US multi-day spaceflight.
Gemini 4, also known as Gemini IV, was the first crewed mission of NASA’s Project Gemini (following Gemini 3), launching in June 1965. It marked the tenth American crewed spaceflight overall, counting two X-15 flights that topped 100 kilometers in altitude. Astronauts James McDivitt and Ed White completed 62 orbits around Earth over four days, making it the first U.S. multi-day flight. The mission’s standout event was the first American spacewalk: White spent about 23 minutes floating freely outside the spacecraft, attached by a tether.
The flight also included the first U.S. attempt at a space rendezvous. McDivitt tried to bring the Gemini capsule close to the spent second stage of the Titan II that had boosted them into orbit, but the maneuver failed.
Additionally, Gemini 4 was the first American mission to carry out a range of scientific experiments in space. Among them was testing a sextant to explore celestial navigation for future Apollo lunar flights.
**Mission Personnel**
**Primary and Backup Crews** NASA selected the primary and backup crews for Gemini 4 on July 28, 1964.
**Support Team** - Mission Director and Flight Director (Red Team): Christopher C. Kraft, Jr. - Flight Director (Blue Team): John D. Hodge - Flight Director (White Team): Eugene F. Kranz - CAPCOMs: Gus Grissom, Roger B. Chaffee, and Eugene Cernan - Worldwide support and recovery team: 10,249 U.S. Department of Defense personnel, 134 aircraft, and 26 ships.
**Mission Parameters** - Mass: 3,570 kg (7,870 lb) - Perigee (insertion): 165.8 km (103.0 mi; 89.5 nmi) - Apogee (insertion): 293.7 km (182.5 mi; 158.6 nmi) - Period: 88.94 min - Inclination: 32.53° - Perigee (last orbit): 150 km (93 mi; 81 nmi) - Apogee (last orbit): 232.8 km (144.7 mi; 125.7 nmi)
**Spacewalk** - Astronaut: Ed White - Date: June 3, 1965 - Hatch opened: 19:34 UTC - Start EVA: 19:39 UTC - End EVA: 20:02 UTC - Duration: 23 minutes - Hatch closed: 20:22 UTC
**Objectives** Gemini 4 was designed as the first multi-day U.S. spaceflight, aiming to prove humans could endure extended time in space. Its four-day, 62-orbit flight was the first U.S. mission to last multiple days, though it did not match the five-day record set by the Soviet Vostok 5 in June 1963. Later Gemini missions would fly longer to demonstrate endurance beyond the time needed for a round trip to the Moon.
A second goal was the first American e
- Mission
- Gemini 4
- Launch date
- June 1965
- Crew
- James McDivitt, Ed White
- Orbits
- 62
- Duration
- 4 days
- First American spacewalk
- Yes
- First US multi-day flight
- Yes
Lore & Background
Gemini 4 was the first US flight to perform many scientific experiments in space, including use of a sextant to investigate celestial navigation for lunar flight in the Apollo program. The flight also included the first attempt to make a space rendezvous as McDivitt attempted to maneuver his craft close to the spent second stage of the Titan II which launched it into orbit, but this was not successful. NASA named primary and backup crews for Gemini IV on July 28, 1964. The spacecraft completed major manufacturing activity, module tests, and equipment installation at McDonnell at the end of January 1965, and was mated to the Titan II launch vehicle at Cape Canaveral Launch Complex 19 on April 23, 1965.
Reader's Guide
Gemini 4 demonstrated that humans could remain in space for extended lengths of time, approaching the Soviet Vostok 5 record. The spacewalk by Ed White, though preceded by Soviet Alexei Leonov, showed the US was gaining on the early Soviet lead in the Space Race. The failed rendezvous attempt highlighted the counter-intuitive nature of orbital mechanics, which NASA later mastered on Gemini 6A. The mission also pioneered live international television coverage via the Early Bird satellite and was the first flight controlled from the new Mission Control Center in Houston. These achievements laid groundwork for the Apollo program's lunar missions.
Did You Know?
- The first American spacewalk by Ed White lasted approximately 23 minutes.
- Gemini 4 was the first US flight to approach the five-day flight of the Soviet Vostok 5.
- The rendezvous attempt with the Titan II upper stage failed due to orbital mechanics issues and lack of radar.
- The launch was broadcast live via the Early Bird satellite to 12 European nations.
More in Successful space missions 1-24
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