Gemini 4

Primary and Backup Crews NASA named primary and backup crews for Gemini IV on July 28, 1964. {{Spaceflight crew 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: • Perigee (insertion): • Apogee (insertion): • Period: 88.94 min • Inclination: 32.53° • Perigee (last orbit): • Apogee (last orbit): Spacewalk • Ed White - EVA - 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 would be the first multi-day space flight by the United States, designed to show that it was possible for humans to remain in space for extended lengths of time. The four-day, 66-orbit flight would approach but not break the five-day record set by the Soviet Vostok 5 in June 1963. Subsequent Gemini flights would be longer, to prove endurance exceeding the time required to fly to the Moon and back. A second objective was the first American extra-vehicular activity (EVA), known popularly as a "space walk". The first space walk had already been performed by Soviet Alexei Leonov on Voskhod 2 in March 1965. NASA moved up the spacewalk from the original schedule, to demonstrate that the US was gaining on the early lead taken by the Soviets in what was known as the Space Race. As late as 11 days before the scheduled June 3 launch, newspapers were reporting NASA saying that it "had not yet determined whether White would be the first American astronaut to expose himself to the elements of space" and that "A decision might not be made until a day or two before launching." A third objective was for Gemini 4 to attempt the first space rendezvous, flying in formation with the spent second stage of its Titan II launch vehicle. ==Preparations==

The Gemini 4 spacecraft completed major manufacturing activity, module tests, and equipment installation at McDonnell at the end of January 1965. The spacecraft was mated to the Titan II launch vehicle at Cape Canaveral Launch Complex 19 on April 23, 1965. Final system tests were performed over several additional weeks. NASA leadership approved the Gemini 4 EVA plan on May 25, 1965; the public was informed on the same day ==Flight==

Launch launch vehicle lifts Gemini 4 into orbit, June 3, 1965. Launched from LC-19 at Cape Kennedy Air Force Station, Florida, Gemini 4 was the first flight to be controlled by the new Mission Control Center at the Manned Spacecraft Center in Houston, Texas, which had to conduct three-shift operations due to the flight's long duration. The broadcast of the launch was itself historic. For the first time an international audience, from 12 European nations, could watch the lift-off on live television via the Early Bird satellite. Press interest, due to the satellite broadcast and the new center in Houston, proved to be so high that NASA had to lease buildings to accommodate the 1,100 print and broadcast journalists who requested accreditation. Flight control shifted from Cape Kennedy to Houston as soon as the vehicle cleared the launch tower. At liftoff, two roll transients caused by misalignment of the Titan first-stage engines occurred; these were quickly corrected by the autopilot. The fuel top-off umbilical failed to detach and was pulled loose when the booster had climbed about . A small oscillation in the pitch and yaw planes resulted from this. Performance of all launch vehicle systems was nearly nominal. Some modifications had been made to the guidance program on Gemini 4's booster to produce a less lofted flight trajectory and a lower altitude at booster engine cut-off (BECO) than on Gemini 3; these were generally successful despite a still somewhat lofted flight path. BECO occurred at T+152 seconds; second-stage engine cut-off (SECO) occurred at T+333 seconds. The spacecraft entered into an orbit. Rendezvous attempt On the first orbit, McDivitt attempted to rendezvous with the spent Titan second stage. This was unsuccessful for a number of reasons: • NASA engineers had not yet worked out the idiosyncrasies of orbital mechanics involved in rendezvous, which are counter-intuitive. Simply thrusting the spacecraft toward the target changed its orbital altitude and velocity relative to the target. When McDivitt tried this, he found himself moving away and downward, as the retrograde thrust lowered his orbit, increasing his speed. • The stage was dumping its residual propellant, causing it to move around in various directions relative to the Gemini. They powered down the spacecraft's maneuvering system, intending to drift for the next two-and-a-half days to conserve the remaining fuel. They also intended to sleep alternate four-hour periods, but this turned out to be extremely difficult with the constant radio communications and the small cabin, about the size of the front seats of a compact car. White's 20-minute space walk was the mission's highlight, with McDivitt's photographs being published worldwide. These also showed White wearing an Omega Speedmaster chronograph watch on his spacesuit sleeve, one of two makes which had been approved by NASA for space use following extensive tests. Omega were unaware of these tests or the fact that its product was going to be used in space, until the photos. The model worn during the spacewalk is now known as the "Ed White" by watch collectors. Experiments Eleven experiments were carried on the spacecraft: As they lacked any means of measuring water intake, they attempted to minimize consumption of it and also reported high amounts of gas bubbles in the water from the water dispenser. They experienced a degree of eye, nose, and throat irritation early in the flight and post-landing. This was attributed to ammonia fumes from the flame retardant used in the cabin, which was changed to a different material on subsequent flights. Reentry by telephone aboard the aircraft carrier USS Wasp The computer failed on the 48th revolution when McDivitt tried to update it for reentry. It would not turn off and eventually stopped working altogether. This was unfortunate for IBM, which had just put an advertisement suggesting that its computers were so reliable that even NASA used them.{{cite web Reentry came on the 62nd revolution. An open-loop rolling reentry (as used in Mercury) had to be used because of the computer failure. The astronauts began rolling the spacecraft at altitude to increase its stability. They started slowing the roll rate at and stopped it by . The drogue parachute deployed shortly after this, and the main deployed at . A malfunctioning thruster caused the roll to be much faster than planned, and the landing was rough. Despite the rough landing, neither of the crew encountered any problems, contrary to NASA doctors' concerns about their landing upright as opposed to on their backs, as in Mercury after four days in space. Even though they landed short of the intended landing target, some ships had already started steaming to the touchdown point, and a helicopter was able to see them land. The prime recovery ship was . The recovery was supported by 10,249 U.S. Department of Defense personnel, 134 aircraft, and 26 ships. Postflight medical examination found the astronauts to be in good health, and no significant physiological changes were found. ==Insignia==

Gemini 4's crew originally intended to call their spacecraft American Eagle, but this was rejected after NASA management issued a memo saying that they did not want a repeat performance of the previous mission, on which Gus Grissom had named his spacecraft Molly Brown. The callsign for the mission became simply Gemini 4. There was no patch flown on the crew's suits, although the one shown here was created after the mission and is on display in McDivitt's museum. Since McDivitt and White were prohibited from naming their spacecraft, they decided to put the American flag on their suits, the first astronauts to do so, although Soviet crews wore the Cyrillic "СССР" on their spacesuit helmets. Previous astronauts had only had the NASA insignia and a strip with their name on their suits. ==Post-flight==

Spacecraft location The spacecraft is on display at the Steven F. Udvar-Hazy Center, Chantilly, Virginia Postage stamp The flight was commemorated on a pair of US postage stamps in 1967. == See also ==