Gemini 4
Encyclopedia
Gemini 4 was the second manned space flight in NASA
's Project Gemini
, occurring in June 1965. It was the tenth manned American
spaceflight (including two X-15 flights at altitudes exceeding 100 kilometres (54 nmi)). Astronauts James McDivitt
and Edward H. White, II circled the Earth 66 times in four days, making it the first US flight to approach the five-day flight of the Soviet
Vostok 5
. The highlight of the mission was the first space walk by an American, during which White floated free outside the spacecraft, tethered to it, for approximately 20 minutes. Both of these accomplishments helped the United States overcome the Soviet Union's early lead in the Space Race
.
The flight also included the first attempt to make a space rendezvous
as McDivitt attempted to maneuver his craft close to the Titan II
upper stage which launched it into orbit, but this was not successful.
The flight was the first American flight to perform many scientific experiment
s in space, including use of a sextant
to investigate the use of celestial navigation
for lunar flight in the Apollo program.
, 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 Aleksei 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 that NASA was saying 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
.
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 Canaveral to Houston as soon as the vehicle cleared the launch tower.
Except for a few moments of pogo oscillation
(axial vibrations in the rocket), the launch came off perfectly, the spacecraft entering into a 87 by orbit.
with the spent Titan second stage. This was unsuccessful for a number of reasons:
After expending almost half his thruster fuel, McDivitt finally gave up, in order to concentrate on the more important EVA objective. (Rendezvous was finally achieved successfully by Wally Schirra
commanding Gemini 6A
in December.) After the rendezvous, Gemini 4's orbit was now 89.2 by. Twenty-two hours into the mission, Mission Control estimated the orbit would decay to 81 by at the end of 63 revolutions.
, they began to depressurize the cabin. Over Hawaii
, White pulled the handle to open his hatch, but the latches failed to move.
Fortunately, McDivitt knew what the problem was, because the hatch had failed to close in a vacuum chamber
test on the ground, after which McDivitt worked with a technician to see what the cause was. A spring, which forced gears to engage in the mechanism, had failed to compress, and McDivitt got to see how the mechanism worked. In flight, he was able to help White get it open, and thought he could get it to latch again.
There were communication problems during the spacewalk. Gemini spacecraft were the first to use a voice-operated switch (known as VOX) on the astronaut's microphones, but McDivitt soon realized his VOX circuit wasn't working properly; he could only hear the Capsule Communicator (CAPCOM) in the push-to-talk setting, but not on VOX (though both astronauts could be heard by each other and the ground.) Plus, while outside the spacecraft, White was unable to receive transmissions from the ground and had to have all messages relayed through McDivitt. McDivitt must have switched to the VOX setting somewhere around the time White was exiting the spacecraft, because at that point, for most of the EVA, neither he nor White responded either to the Hawaii CAPCOM, or to the Houston CAPCOM, Gus Grissom
. Grissom tried to talk to Gemini 4 a total of 40 times in 13 minutes before he got a response.
Tied to a tether, White floated out of the spacecraft, using a Hand-Held Maneuvering Unit (informally called a "zip gun") which expelled pressurized oxygen to provide thrust for controlling his travel. He went fifteen feet (five meters) out, and began to experiment with maneuvering. He found it easy, especially the pitch and yaw, although he thought the roll would use too much gas. He maneuvered around the spacecraft while McDivitt took photographs. White enjoyed the experience, but exhausted the HHMU gas sooner than he would have liked.
White was running up against two factors which constrained the time for his EVA: loss of signal from the Bermuda tracking station
, and crossing the solar terminator
. The flight controller
s were becoming increasingly frustrated with their inability to remind White of the time constraint, because they didn't want the first EVA to be performed in darkness, or out of communication with Earth. Finally McDivitt decided to take his microphone off of VOX:
White tried to use taking more pictures as an excuse to stay out longer, and McDivitt had to coax him in. He finally came back in after a total of approximately 20 minutes. He said, "It's the saddest moment of my life." By the time he got in, the spacecraft had entered darkness.
The hatch proved to be as stubborn to relatch as it was to open. This would have been disastrous, resulting in both men's deaths on reentry. But McDivitt was able to fix the mechanism once again, so White could close it. The mission plan called for opening the hatch again to throw out White's now-unnecessary EVA equipment, but McDivitt elected not to do this, instead keeping the unnecessary equipment on board for the rest of the flight.
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.
s were carried on the spacecraft
:
There were four engineering experiments:
which had just put an advertisement in the Wall Street Journal saying that its computers were so reliable that even NASA used them. The computer failure meant that the capsule would not be able to perform a closed-loop lifting reentry as planned.
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 65 nautical miles (120.4 km) altitude to increase its stability. They started slowing the roll rate at 89000 feet (27.1 km) and stopped it by 39000 feet (11.9 km). The drogue parachute
deployed shortly after this, and the main deployed at 10600 feet (3.2 km). A malfunctioning thruster caused the roll to be much faster than planned, and the landing was rough. Neither of the crew encountered any problems, however, 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 43 nautical miles (79.6 km) 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 USS Wasp
.
The recovery was supported by 10,249 U.S. Department of Defense personnel, 134 aircraft, and 26 ships.
The callsign for the mission became simply Gemini 4. There was no patch flown on the crew's suits, although the one shown here, created after the fact, 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.
The flight was commemorated on a pair of US postage stamps in 1967.
, Washington, D.C.
.
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Project Gemini
Project Gemini
Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966....
, occurring in June 1965. It was the tenth manned American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
spaceflight (including two X-15 flights at altitudes exceeding 100 kilometres (54 nmi)). Astronauts James McDivitt
James McDivitt
James Alton McDivitt is a former NASA astronaut and engineer who flew in the Gemini and Apollo programs. He commanded the Gemini 4 flight in which Edward H. White performed the first US space walk, and later the Apollo 9 flight which was the first manned Earth orbital test of the Apollo Lunar...
and Edward H. White, II circled the Earth 66 times in four days, making it the first US flight to approach the five-day flight of the Soviet
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
Vostok 5
Vostok 5
-Backup crew:-Reserve crew:-Mission parameters:*Mass *Apogee: *Perigee: *Inclination: 64.9°*Period: 88.4 minutes...
. The highlight of the mission was the first space walk by an American, during which White floated free outside the spacecraft, tethered to it, for approximately 20 minutes. Both of these accomplishments helped the United States overcome the Soviet Union's early lead in the Space Race
Space Race
The Space Race was a mid-to-late 20th century competition between the Soviet Union and the United States for supremacy in space exploration. Between 1957 and 1975, Cold War rivalry between the two nations focused on attaining firsts in space exploration, which were seen as necessary for national...
.
The flight also included the first attempt to make a space rendezvous
Space rendezvous
A space rendezvous is an orbital maneuver during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance . Rendezvous requires a precise match of the orbital velocities of the two spacecraft, allowing them to remain at a constant...
as McDivitt attempted to maneuver his craft close to the Titan II
Titan II GLV
The Titan II GLV or Gemini-Titan was an American expendable launch system derived from the Titan II missile, which was used to launch twelve Gemini missions for NASA between 1964 and 1966...
upper stage which launched it into orbit, but this was not successful.
The flight was the first American flight to perform many scientific experiment
Experiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
s in space, including use of a sextant
Sextant
A sextant is an instrument used to measure the angle between any two visible objects. Its primary use is to determine the angle between a celestial object and the horizon which is known as the altitude. Making this measurement is known as sighting the object, shooting the object, or taking a sight...
to investigate the use of celestial navigation
Celestial navigation
Celestial navigation, also known as astronavigation, is a position fixing technique that has evolved over several thousand years to help sailors cross oceans without having to rely on estimated calculations, or dead reckoning, to know their position...
for lunar flight in the Apollo program.
Crew
Backup Crew
Objectives
Gemini 4 would be the first multi-day space flight by the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, designed to show that it was possible for humans to remain in space
Space
Space is the boundless, three-dimensional extent in which objects and events occur and have relative position and direction. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum...
for extended lengths of time. The four-day, 66-orbit
Orbital period
The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...
flight would approach but not break the five-day record set by the Soviet
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
Vostok 5
Vostok 5
-Backup crew:-Reserve crew:-Mission parameters:*Mass *Apogee: *Perigee: *Inclination: 64.9°*Period: 88.4 minutes...
in June 1963. Subsequent Gemini flights would be longer, to prove endurance exceeding the time required to fly to the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
and back.
A second objective was the first American extra-vehicular activity
Extra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
(EVA), known popularly as a "space walk". The first space walk had already been performed by Soviet Aleksei Leonov
Aleksei Leonov
Alexey Arkhipovich Leonov is a retired Soviet/Russian cosmonaut and Air Force Major General who, on 18 March 1965, became the first human to conduct a space walk.-Biography:...
on Voskhod 2
Voskhod 2
Voskhod 2 was a Soviet manned space mission in March 1965. Vostok-based Voskhod 3KD spacecraft with two crew members on board, Pavel Belyaev and Alexei Leonov, was equipped with an inflatable airlock...
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
Space Race
The Space Race was a mid-to-late 20th century competition between the Soviet Union and the United States for supremacy in space exploration. Between 1957 and 1975, Cold War rivalry between the two nations focused on attaining firsts in space exploration, which were seen as necessary for national...
. As late as 11 days before the scheduled June 3 launch, newspapers were reporting that NASA was saying 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
Space rendezvous
A space rendezvous is an orbital maneuver during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance . Rendezvous requires a precise match of the orbital velocities of the two spacecraft, allowing them to remain at a constant...
, flying in formation with the spent second stage of its Titan II
Titan II GLV
The Titan II GLV or Gemini-Titan was an American expendable launch system derived from the Titan II missile, which was used to launch twelve Gemini missions for NASA between 1964 and 1966...
launch vehicle
Launch vehicle
In spaceflight, a launch vehicle or carrier rocket is a rocket used to carry a payload from the Earth's surface into outer space. A launch system includes the launch vehicle, the launch pad and other infrastructure....
.
Launch
Launched from LC-19Cape Canaveral Air Force Station Launch Complex 19
Launch Complex 19 is a deactivated launch site on Cape Canaveral Air Force Station, Florida used by NASA to launch all of the Gemini manned spaceflights. It was also used by unmanned Titan I and Titan II launch vehicles....
at Cape Kennedy Air Force Station
Cape Canaveral Air Force Station
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, Gemini 4 was the first flight to be controlled by the new Mission Control Center at the Manned Spacecraft Center in Houston, Texas
Houston, Texas
Houston is the fourth-largest city in the United States, and the largest city in the state of Texas. According to the 2010 U.S. Census, the city had a population of 2.1 million people within an area of . Houston is the seat of Harris County and the economic center of , which is the ...
, 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
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
via the Early Bird
Intelsat I
Intelsat I was the first communications satellite to be placed in geosynchronous orbit, on April 6, 1965...
satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
. Press
Mass media
Mass media refers collectively to all media technologies which are intended to reach a large audience via mass communication. Broadcast media transmit their information electronically and comprise of television, film and radio, movies, CDs, DVDs and some other gadgets like cameras or video consoles...
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 Canaveral to Houston as soon as the vehicle cleared the launch tower.
Except for a few moments of pogo oscillation
Pogo oscillation
Pogo oscillation is a potentially dangerous type of self-excited combustion oscillation in liquid fuel rocket engines. This oscillation results in variations of thrust from the engines, causing variations of acceleration on the rocket's structure, giving variations in fuel pressure and flow rate....
(axial vibrations in the rocket), the launch came off perfectly, the spacecraft entering into a 87 by orbit.
Rendezvous attempt
On the first orbit, McDivitt attempted to rendezvousSpace rendezvous
A space rendezvous is an orbital maneuver during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance . Rendezvous requires a precise match of the orbital velocities of the two spacecraft, allowing them to remain at a constant...
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.
- There were only two running lights on the stage, which made it hard at times for McDivitt to determine its orientation. McDivitt concluded that a rendezvous target should have at least three lights.
- There was no radar on board Gemini 4 to give a precise range to the target, so the astronauts had to rely on their visual depth perception to estimate the range, and this differed for the two men. Initially McDivitt estimated the distance at 400–500 ft (121.9–152.4 m), while White believed it was closer ("a little over 200 feet (61 m)"). At the worst point, McDivitt estimated it was about a half mile (800 meters) away, while White's estimate was three-quarters of a mile (1200 meters). McDivitt estimated he was able to get as close as 200 feet (61 m), but now White's estimate was between 850 and 1000 ft (259.1 and 304.8 m).
After expending almost half his thruster fuel, McDivitt finally gave up, in order to concentrate on the more important EVA objective. (Rendezvous was finally achieved successfully by Wally Schirra
Wally Schirra
Walter Marty Schirra, Jr. was an American test pilot, United States Navy officer, and one of the original Mercury 7 astronauts chosen for the Project Mercury, America's effort to put humans in space. He is the only person to fly in all of America's first three space programs...
commanding Gemini 6A
Gemini 6A
-Backup crew:-Mission parameters:* Mass: * Perigee: * Apogee: * Inclination: 28.97°* Period: 88.7 min-Stationkeeping with GT-7:* Start: December 15, 1965 19:33 UTC* End: December 16, 1965 00:52 UTC-Objectives:...
in December.) After the rendezvous, Gemini 4's orbit was now 89.2 by. Twenty-two hours into the mission, Mission Control estimated the orbit would decay to 81 by at the end of 63 revolutions.
Extra-vehicular activity (EVA)
Originally planned for the second revolution, the astronauts postponed the EVA until the third after McDivitt decided that White, following the stress of the launch and the failed rendezvous, looked tired and hot. After a rest, the pair finished performing the checklist for the EVA. Flying over Carnarvon, AustraliaCarnarvon, Western Australia
Carnarvon is a coastal town situated approximately 900 kilometres north of Perth, Western Australia. It lies at the mouth of the Gascoyne River on the Indian Ocean. The popular Shark Bay world heritage area lies to the south of the town and the Ningaloo Reef lies to the north...
, they began to depressurize the cabin. Over Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, White pulled the handle to open his hatch, but the latches failed to move.
Fortunately, McDivitt knew what the problem was, because the hatch had failed to close in a vacuum chamber
Vacuum chamber
A vacuum chamber is a rigid enclosure from which air and other gases are removed by a vacuum pump. The resulting low pressure, commonly referred to as a vacuum, allows researchers to conduct physical experiments or to test mechanical devices which must operate in outer space...
test on the ground, after which McDivitt worked with a technician to see what the cause was. A spring, which forced gears to engage in the mechanism, had failed to compress, and McDivitt got to see how the mechanism worked. In flight, he was able to help White get it open, and thought he could get it to latch again.
There were communication problems during the spacewalk. Gemini spacecraft were the first to use a voice-operated switch (known as VOX) on the astronaut's microphones, but McDivitt soon realized his VOX circuit wasn't working properly; he could only hear the Capsule Communicator (CAPCOM) in the push-to-talk setting, but not on VOX (though both astronauts could be heard by each other and the ground.) Plus, while outside the spacecraft, White was unable to receive transmissions from the ground and had to have all messages relayed through McDivitt. McDivitt must have switched to the VOX setting somewhere around the time White was exiting the spacecraft, because at that point, for most of the EVA, neither he nor White responded either to the Hawaii CAPCOM, or to the Houston CAPCOM, Gus Grissom
Gus Grissom
Virgil Ivan Grissom , , better known as Gus Grissom, was one of the original NASA Project Mercury astronauts and a United States Air Force pilot...
. Grissom tried to talk to Gemini 4 a total of 40 times in 13 minutes before he got a response.
Tied to a tether, White floated out of the spacecraft, using a Hand-Held Maneuvering Unit (informally called a "zip gun") which expelled pressurized oxygen to provide thrust for controlling his travel. He went fifteen feet (five meters) out, and began to experiment with maneuvering. He found it easy, especially the pitch and yaw, although he thought the roll would use too much gas. He maneuvered around the spacecraft while McDivitt took photographs. White enjoyed the experience, but exhausted the HHMU gas sooner than he would have liked.
White was running up against two factors which constrained the time for his EVA: loss of signal from the Bermuda tracking station
Naval Air Station Bermuda
Naval Air Station Bermuda , was located on St. David's Island, Bermuda from 1970 to 1995, on the former site of Kindley Air Force Base...
, and crossing the solar terminator
Terminator (solar)
A terminator, twilight zone or "grey line" is a moving line that separates the illuminated day side and the dark night side of a planetary body...
. The flight controller
Flight controller
Flight controllers are personnel who aid in the operations of a space flight, working in Mission Control Centers such as NASA's Mission Control Center, or ESA's Operations Center. Flight controllers sit at computer consoles and use telemetry to monitor in real time various technical aspects of a...
s were becoming increasingly frustrated with their inability to remind White of the time constraint, because they didn't want the first EVA to be performed in darkness, or out of communication with Earth. Finally McDivitt decided to take his microphone off of VOX:
- McDivitt, to White: I'm going out to PUSH-TO-TALK and see what the Flight Director has got to say.
- Flight DirectorFlight directorThe term flight director can refer to any one of the following:* the flight controller of a space flight* the flight director of an aviation navigation system...
Chris KraftChristopher C. Kraft, Jr.Christopher Columbus Kraft, Jr. is a retired NASA engineer and manager who was instrumental in establishing the agency's Mission Control operation...
, to Grissom: The flight director says, get back in! (Kraft was not on the air-to-ground loop with the astronauts.)
- McDivitt: Gus, this is Jim. Got any message for us?
- Grissom: Gemini 4, get back in!
- McDivitt: Okay. ... (to White): ... They want you to come back in now.
White tried to use taking more pictures as an excuse to stay out longer, and McDivitt had to coax him in. He finally came back in after a total of approximately 20 minutes. He said, "It's the saddest moment of my life." By the time he got in, the spacecraft had entered darkness.
The hatch proved to be as stubborn to relatch as it was to open. This would have been disastrous, resulting in both men's deaths on reentry. But McDivitt was able to fix the mechanism once again, so White could close it. The mission plan called for opening the hatch again to throw out White's now-unnecessary EVA equipment, but McDivitt elected not to do this, instead keeping the unnecessary equipment on board for the rest of the flight.
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
Compact car
A compact car , or small family car , is a classification of cars which are larger than a supermini but smaller than or equal to a mid-size car...
.
White's 20-minute space walk was the mission's highlight, with McDivitt's photographs being published worldwide.
Experiments
Eleven experimentExperiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
s were carried on the spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
:
- Experiment D-8 used five dosimeters to measured the radiation in the spacecraft environment. Of particular interest was the South Atlantic AnomalySouth Atlantic AnomalyThe South Atlantic Anomaly is an area where the Earth's inner Van Allen radiation belt comes closest to the Earth's surface. This leads to an increased flux of energetic particles in this region and exposes orbiting satellites to higher than usual levels of radiation...
. - Experiment D-9 was an experiment in simple spacecraft navigation where the crew used a sextantSextantA sextant is an instrument used to measure the angle between any two visible objects. Its primary use is to determine the angle between a celestial object and the horizon which is known as the altitude. Making this measurement is known as sighting the object, shooting the object, or taking a sight...
to measure their position using the stars. The objective was to investigate the feasibility of using this technique for lunar flights on the Apollo program. - Experiments S-5 and S-6 were both photography experiments where they used a 70-millimeter HasselbladHasselbladVictor Hasselblad AB is a Swedish manufacturer of medium-format cameras and photographic equipment based in Gothenburg, Sweden.The company is best known for the medium-format cameras it has produced since World War II....
camera to photograph the weather and terrain below them. - There were two medical experiments: M-3 and M-4. The first was a bungee cordBungee cordA bungee cord , also known as a shock cord, is an elastic cord composed of one or more elastic strands forming a core, usually covered in a woven cotton or polypropylene sheath...
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 spectrometerSpectrometerA spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization...
, - MSC-3 was a tri-axis magnetometerMagnetometerA magnetometer is a measuring instrument used to measure the strength or direction of a magnetic field either produced in the laboratory or existing in nature...
and MSC-10 involved the crew photographing the red-blue Earth limb.
Reentry
The computer failed on the 48th revolution. This was unfortunate for IBMIBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
which had just put an advertisement in the Wall Street Journal saying that its computers were so reliable that even NASA used them. The computer failure meant that the capsule would not be able to perform a closed-loop lifting reentry as planned.
Reentry came on the 62nd revolution. An open-loop
Open-loop controller
An open-loop controller, also called a non-feedback controller, is a type of controller that computes its input into a system using only the current state and its model of the system....
rolling reentry (as used in Mercury) had to be used because of the computer failure. The astronauts began rolling the spacecraft at 65 nautical miles (120.4 km) altitude to increase its stability. They started slowing the roll rate at 89000 feet (27.1 km) and stopped it by 39000 feet (11.9 km). The drogue parachute
Drogue parachute
A drogue parachute is a parachute designed to be deployed from a rapidly moving object in order to slow the object, or to provide control and stability, or as a pilot parachute to deploy a larger parachute...
deployed shortly after this, and the main deployed at 10600 feet (3.2 km). A malfunctioning thruster caused the roll to be much faster than planned, and the landing was rough. Neither of the crew encountered any problems, however, 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 43 nautical miles (79.6 km) short of the intended landing target, some ships had already started steaming to the touchdown point and a helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
was able to see them land. The prime recovery ship was USS Wasp
USS Wasp (CV-18)
USS Wasp was one of 24 s built during World War II for the United States Navy. The ship, the ninth US Navy ship to bear the name, was originally named Oriskany, but was renamed while under construction in honor of the previous , which was sunk 15 September 1942...
.
The recovery was supported by 10,249 U.S. Department of Defense personnel, 134 aircraft, and 26 ships.
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, created after the fact, is on display in McDivitt's museum. Since McDivitt and White were prohibited from naming their spacecraft, they decided to put the American flag
Flag of the United States
The national flag of the United States of America consists of thirteen equal horizontal stripes of red alternating with white, with a blue rectangle in the canton bearing fifty small, white, five-pointed stars arranged in nine offset horizontal rows of six stars alternating with rows...
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.
The flight was commemorated on a pair of US postage stamps in 1967.
Spacecraft location
The spacecraft is on permanent display at the National Air and Space MuseumNational Air and Space Museum
The National Air and Space Museum of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world. It was established in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and...
, Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
.
Mission parameters
- MassMassMass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
: 7880 pounds (3,574.3 kg) - PerigeePerigeePerigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
(insertion): 89.5 nautical miles (165.8 km) - Apogee (insertion): 158.6 nautical miles (293.7 km)
- PeriodOrbital periodThe orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...
: 88.94 min - InclinationInclinationInclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
: 32.53° - PerigeePerigeePerigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
(last orbit): 81 nautical miles (150 km) - Apogee (last orbit): 125.7 nautical miles (232.8 km)
Spacewalk
- Edward H. White - EVA - June 3, 1965
- Hatch opened: 19:34 UTC
- Start EVA: 19:46 UTC
- End EVA: 20:06 UTC
- Duration: 20 minutes
- Hatch closed: 20:10 UTC
See also
- Extra-vehicular activityExtra-vehicular activityExtra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
- List of spacewalks
- SplashdownSplashdown (spacecraft landing)Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by American manned spacecraft prior to the Space Shuttle program. It is also possible for the Russian Soyuz spacecraft and Chinese Shenzhou spacecraft to land in water, though this is only a contingency...