Gemini 4

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Gemini 4
Mission insignia
Gemini 4 insignia
Mission statistics
Mission name: Gemini 4
Call sign: Gemini 4
Number of
Launch: June 3, 1965
15:15:59.562 UTC
Cape Canaveral
LC 19
Open hatch:
Start walk:
End walk:
Close hatch:
June 3, 1965
19:34 UTC
19:46 UTC
20:06 UTC
20:10 UTC
Landing: June 7, 1965
16:12:11 UTC
Template:Coor dm
Duration: 4 days, 1 hour
56 minutes
2 seconds
Distance traveled: ~2,782,486 km
Orbits: 62
(1st orbit)
282.1 km
(1st orbit)
162.3 km
(1st orbit)
88.94 min
Inclination: 32.53 deg
Mass: 3,574 kg
Crew Picture
Gemini 4 crew portrait (L-R: White, McDivitt)
Gemini 4 crew portrait
(L-R: White, McDivitt)
Gemini 4 Crew

Gemini 4 (officially Gemini IV) was a 1965 manned space flight in NASA's Gemini program. It was the 2nd manned Gemini flight, the 10th manned American flight and the 18th spaceflight of all time (includes X-15 flights over 100 km).


Backup crew

Mission parameters

Space walk

  • White - EVA - June 3, 1965
  • Open hatch: 19:34 UTC
  • Start EVA: 19:46 UTC
  • End EVA: 20:06 UTC
  • Close hatch: 20:10 UTC
  • Duration: 20 minutes

See also


The plan for this four-day, 62-orbit mission was for Gemini IV to fly in formation with the spent second stage of its Titan 2 booster in orbit. On this first attempt, however, space flight engineers learned something about the complication of orbital rendezvous. Thrusting toward their target, the astronauts only moved farther away. They finally gave up after using nearly half their fuel. (On later rendezvous missions, a spacecraft chasing another in orbit would first drop to a lower, faster orbit before rising again.) The mission's highlight was White's 22-minute space walk, the first ever for an American. Tied to a tether and using a handheld "zip gun" to maneuver himself, White swam through space while McDivitt took photographs. Gemini IV set a record for flight duration, and eased fears about the medical consequences of longer missions. It also was the first use of the new Mission Control Center outside Houston, which because of the long duration, had to conduct the first three-shift operations.

Gemini 4 was the first multi day space flight by the United States. It had been realised that in order to get to the Moon you would have to show that it was possible for a man to stay in space for the length of time it would take for him to get there and back.

Also on this mission was the first ever American Extra-vehicular activity (EVA). This objective was not originally intended to be part of the mission but after Aleksei Leonov on Voskhod 2 had performed the first ever it was necessary to give the appearance that the US was not falling behind.


The launch was also historical for the fact that for the first time there was an international audience watching it live. It was broadcast on television to 12 European nations via the Early Bird satellite. It would also be the first time that the Mission Control center at Houston had been used. Due to these factors the press interest was high. NASA had to lease buildings to house all 1,100 journalists who requested accredition.

The launch was perfect except for a few moments of pogo (lateral motion in the rocket), with the spacecraft entering into a 163 by 282 kilometres orbit. One of the first objectives was to see if Gemini could station keep with its spent rocket stage. This turned out to be harder than anticipated. The crew had little training in the idiosyncrasies of orbital mechanics. Therefore, they couldn't understand it when they fired their thrusters in the direction of the rocket stage and found it moved away and downward.

After several attempts over the first orbit to get closer to the stage the crew gave up. They decided that the EVA was more important than the rendezvous, something that would be performed on later missions.

Extra-Vehicular Activity (EVA)

They postponed the EVA until the third orbit after McDivitt decided that White looked tired and hot. After the rest they finished the checklist that would get them ready for the EVA. Over Carnarvon, Australia, they began to depressurise the cabin. A spring failed to compress in the hatch mechanism meaning that the hatch wouldn't open at first. It finally did after some pushing and shoving.
Ed White performing the first American EVA

White then floated out of the hatch and fired his nitrogen powered gun to move him out of the spacecraft. He travelled five metres and began to experiment with manoevering. He found it to be easy, especially the pitch and yaw, though he thought the roll would use too much fuel. After 15 minutes 40 seconds he was told to reenter the spacecraft. He said "It's the saddest moment of my life." The hatch was difficult to relatch but it finally did with McDivitt pulling on White and White pulling on the hatch handle.

They powered down the spacecraft intending to drift for the next two and a half days. They also intended to sleep alternate four hour periods but this turned out to be nearly impossible with the constant radio communications and the small cabin meaning each was almost in the other person's lap.


Eleven experiments were carried on the spacecraft. D-8 was five dosimeters that measured the radiation in the spacecraft environment. Of particular interest was the South Atlantic Anomaly. D-9 was an experiment in simple spacecraft navigation where the crew used a sextant to measure their position using the stars.

5-5 and 5-6 were both photography experiments where they used a 70-millimeter Hasselblad camera to photograph the weather and terrain below them. There were two medical experiments: M-3 and M-4. The first was a bungee cord that the crew used for exercise. They said, after the mission, that this got harder as the mission went on, though this may have been due to a lack of sleep. The second was the Phonocardiogram experiment, which had sensors attached to their bodies that measured heartbeat rates, especially during liftoff, EVA, and reentry.

There were four engineering experiments. MSC-1 measured the Electrostatic Charge in the spacecraft, MSC-2 was a Proton-Electron Spectrometer, MSC-3 was a Tri-Axis Magnetometer and MSC-10 involved the crew photographing the red-blue Earth limb.

The computer failed on the 48th revolution. This was unfortunate for IBM who had just put an advertisement in the Wall Street Journal saying that their computers were so reliable that even NASA used them! The computer failure meant that the capsule would not be able to perform a lifting reentry as planned.


Reentry came on the 62nd revolution. They started rolling the spacecraft at 120,000 metres to increase its stabilty. They started slowing this rolling at 27,000 metres and it had stopped by 12,000 metres. The drogue parachute deployed shortly after this and the main deployed at 3,230 metres. The landing was rough but neither of the crew encountered any problems. Even though they were 80 kilometres short of the intended landing point, some ships had already started steaming to the touchdown point and a helicopter was able to see them land.

The Gemini 4 mission was supported by the following U.S. Department of Defense resources: 10,249 personnel, 134 aircraft and 26 ships.


There was no patch or callsign for this mission. The NASA management sent a memo around saying that they didn't want a repeat performance of the previous mission where Gus Grissom had named his spacecraft Molly Brown. Gemini 4's crew had intended to call their mission American Eagle, but this was scuttled. As the crew were unable to name their spacecraft they decided to put the American flag on their suits, surprisingly the first crew to do so.

Capsule location

File:Gemini 4 Inside National Air and Space Museum.JPG
Gemini 4 on display in 2004 (inside capsule).

The capsule is on display at the National Air and Space Museum, Washington D.C..

External links

Template:Project Gemini

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