Mercury-Atlas 5
Encyclopedia
Mercury-Atlas 5 was an American unmanned spaceflight
of the Mercury program
. It was launched on November 29, 1961 with Enos the Chimp, a chimpanzee
, aboard. The craft orbited the Earth
twice and splashed down about 200 miles south of Bermuda
.
and Gherman Titov
into orbit
during the Vostok 1
and Vostok 2
manned orbital flights. At that time NASA
was still debating placing a chimpanzee in orbit as part of the Mercury-Atlas
subprogram, with NASA headquarters questioning the wisdom of the Manned Spacecraft Center
launching another unmanned Mercury mission. The NASA Public Affairs Office issued a press release stating "The men in charge of Project Mercury have insisted on orbiting the chimpanzee
as a necessary preliminary checkout of the entire Mercury program before risking a human astronaut." prior to the flight.
# 9 and Atlas
# 93-D. On February 24, 1961 spacecraft # 9 arrived at Cape Canaveral
. It took forty weeks of preflight preparation. This was the longest preparation time in the Mercury program
. The mission of spacecraft # 9 kept changing. It had been first been configured for a suborbital instrumented flight, then for a suborbital chimpanzee flight, then a three-orbit instrumented mission, and finally for the orbital flight that Enos flew.
MA-5 was planned as a close approximation of the upcoming MA-6 manned orbital mission.
Mercury-Atlas 5 would be launched from Complex 14
at Cape Canaveral
on a heading 72.51 degrees east of north. Orbital insertion of the Mercury spacecraft would occur 480 miles (772.5 km) from Cape Canaveral. The altitude would be 100 miles (160.9 km) and the speed would be 25695 feet per second (7,831.8 m/s). Retrofire was planned to take place at 4 hours, 32 minutes, and 26 seconds after launch. The spacecraft would land 21 minutes and 49 seconds after retrofire. Reentry temperatures were expected to reach 3000 °F (1,648.9 °C) on the heatshield, 2000 °F (1,093.3 °C) on the antenna housing, 1080 °F (582.2 °C) on the cylindrical section, and 1260 °F (682.2 °C) on the conical section. The spent Atlas sustainer engine was expected to reenter the atmosphere after 9⅓ orbits.
On October 29, 1961, three chimps and 12 medical specialists moved into quarters at the Cape to prepare for the flight. The name given to "Enos," the chimp selected to fly the MA-5 mission, in Hebrew
means "man". Enos's backups were (in order possible call-up) Duane, Jim, Rocky and Ham (the MR-2 veteran). Enos was from Cameroon
, Africa, (originally called Chimp # 81), and was purchased by the USAF on April 3, 1960.
On November 29, 1961, about five hours before launch, Enos and his spacesuit-couch were inserted in the spacecraft. During the countdown
, various holds took 2 hours and 38 minutes. Liftoff
came at 15:08 UTC. The Atlas launched the MA-5 spacecraft into an orbit of 99 by.
The turnaround and damping
maneuver consumed 6 pounds (2.7 kg) of the 61.5 pounds (27.9 kg) of control fuel
aboard. The spacecraft used less fuel than the MA-4 did during the same maneuver. MA-5 assumed its planned 34 degree orbital attitude and after that, through the first orbit
the thrusters
used only 1.5 pound (0.680388555 kg) of fuel to maintain a correct position.
At the end of the first orbit, ground controllers noticed the capsule
clock was 18 seconds too fast. As it passed over Cape Canaveral a command was sent to update the clock to the correct time. The Mercury Control Center at Cape Canaveral received information that all spacecraft systems were in good condition.
Then as the MA-5 passed over the Atlantic
tracking ship at the beginning of the second orbit, indications were received that inverter temperatures were rising. The environmental control system
malfunction was also confirmed by Canary Island trackers. Abnormal heating had occurred on earlier flights; in such cases, inverters had continued working or had been switched to standby. There was no alarm at Mercury Control. When the spacecraft reached Muchea
, Australia, high thruster signals and capsule motion excursions were detected. Other data indicated that the 34 degree orbit mode was being maintained. When the MA-5 crossed the tracking station at Woomera, Australia, attitude control problems were not detected, so earlier reports were discounted.
s to fail. The failed thruster allowed the spacecraft to drift from its normal attitude. This drift caused the automatic stabilization and control system to correct the spacecraft attitude. The spacecraft would swing back into the normal 34 degree orbital attitude, and the sequence would start again. The spacecraft repeated this drift and correction process nine times before retrofire. It did it once more between retrofire and the receipt of the 0.05 g (0.49 m/s²) light telemetry signal. The remaining thrusters used 9.5 pounds (4.3 kg) of fuel to keep the spacecraft properly aligned during the second orbit. Each loss of attitude cost over 1 pound (0.45359237 kg) of fuel as compared with the entire first orbit consumption of only 1.5 pound (0.680388555 kg).
In addition to the attitude control problems, the environmental control system started having problems during the second orbit. The couch-suit circuit temperature rapidly rose from 65 to 80 °F (18 to 26 °C). This was an indication that the heat exchanger was freezing. The rise in suit temperature caused Enos' body temperature to rise to 99 °F (37.2 °C), then to 100 °F (37.8 °C). The medical observers began to worry about the chimp's condition. At 100.5 °F (38.1 °C), his body temperature stabilized. This indicated that the environmental system had started to function again. The cooling system seemed to correct itself, but the attitude problems continued.
As the spacecraft neared Hawaii on its second orbit, medical monitors were willing to let Enos continue the flight for a third orbit. However, engineers were concerned about fuel consumption. They worried that after a third orbit, there would not be enough fuel for attitude control during reentry.
Flight Director Christopher Kraft
alerted the Hawaii controllers to be ready to initiate retrofire to bring the spacecraft down in the Pacific, if necessary. He also alerted controllers at Point Arguello
, California, to be ready to initiate retrofire as MA-5 passed over their position. He allowed the spacecraft to continue to its normal second orbit retrofire position near California. Twelve seconds before the retrofire point was reached for the normal second-orbit Atlantic primary recovery point, Kraft decided to bring Enos back to Earth. The chief flight controller at Point Arguello executed the command.
There was one more attitude control excursion early in reentry; after that, the rest of reentry and recovery were uneventful. The destroyers and and a P5M
aircraft were waiting for the spacecraft at Station 8, the predicted landing point. Three hours and 13 minutes after launch and nine minutes before splashdown, the aircraft spotted the spacecraft at an altitude of 5000 feet (1,524 m) descending on its main parachute. The information was relayed to the Stormes and the Compton, who were 30 miles (48.3 km) away. The spacecraft recovery aids were all functioning, except for the SARAH beacon. During the descent, the aircraft continued to circle and report landing events. It remained in the area until the Stormes arrived, an hour and 15 minutes after the landing. The Stormes hauled Enos and his spacecraft aboard. On the deck of the Stormes, the MA-5 hatch was blown explosively. It was released from outside the capsule by a pulling a lanyard. Blowing the hatch caused the spacecraft "picture" window to crack.
On November 4, 1962, Enos died of dysentery caused by shigellosis
, which was resistant to antibiotics of the time. He had been under constant observation for two months before his death. Pathologists at Holloman reported that they found no symptom that could be attributed or related to his space flight a year before.
The Mercury spacecraft had now been qualified to carry a human into orbit.
Spaceflight
Spaceflight is the act of travelling into or through outer space. Spaceflight can occur with spacecraft which may, or may not, have humans on board. Examples of human spaceflight include the Russian Soyuz program, the U.S. Space shuttle program, as well as the ongoing International Space Station...
of the Mercury program
Mercury program
Mercury Program might refer to:*the first successful American manned spaceflight program, Project Mercury*an American post-rock band, The Mercury Program...
. It was launched on November 29, 1961 with Enos the Chimp, a chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
, aboard. The craft orbited the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
twice and splashed down about 200 miles south of Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
.
History
By November 1961, the Soviets had launched Yuri GagarinYuri Gagarin
Yuri Alekseyevich Gagarin was a Soviet pilot and cosmonaut. He was the first human to journey into outer space, when his Vostok spacecraft completed an orbit of the Earth on April 12, 1961....
and Gherman Titov
Gherman Titov
Gherman Stepanovich Titov was a Soviet cosmonaut who, on August 6, 1961, became the second human to orbit the Earth aboard Vostok 2, preceded by Yuri Gagarin on Vostok 1...
into orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
during the Vostok 1
Vostok 1
Vostok 1 was the first spaceflight in the Vostok program and the first human spaceflight in history. The Vostok 3KA spacecraft was launched on April 12, 1961. The flight took Yuri Gagarin, a cosmonaut from the Soviet Union, into space. The flight marked the first time that a human entered outer...
and Vostok 2
Vostok 2
Vostok 2 was a Soviet space mission which carried cosmonaut Gherman Titov into orbit for a full day in order to study the effects of a more prolonged period of weightlessness on the human body...
manned orbital flights. At that time NASA
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...
was still debating placing a chimpanzee in orbit as part of the Mercury-Atlas
Mercury-Atlas
Mercury-Atlas was a subprogram of Project Mercury which comprised most of the flights and tests using the Atlas LV-3B launch vehicle. The Atlas was also used for one Mercury flight under the Big Joe subprogram.- Mission numbering :...
subprogram, with NASA headquarters questioning the wisdom of the Manned Spacecraft Center
Lyndon B. Johnson Space Center
The Lyndon B. Johnson Space Center is the National Aeronautics and Space Administration's center for human spaceflight training, research and flight control. The center consists of a complex of 100 buildings constructed on 1,620 acres in Houston, Texas, USA...
launching another unmanned Mercury mission. The NASA Public Affairs Office issued a press release stating "The men in charge of Project Mercury have insisted on orbiting the chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
as a necessary preliminary checkout of the entire Mercury program before risking a human astronaut." prior to the flight.
Launch and orbit
The flight used Mercury spacecraftSpacecraft
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....
# 9 and Atlas
Atlas LV-3B
The Atlas LV-3B, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a man-rated expendable launch system used as part of the United States Project Mercury to send astronauts into low Earth orbit. It was derived from the SM-65D Atlas missile, and was a member of the Atlas family of...
# 93-D. On February 24, 1961 spacecraft # 9 arrived at Cape Canaveral
Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...
. It took forty weeks of preflight preparation. This was the longest preparation time in the Mercury program
Mercury program
Mercury Program might refer to:*the first successful American manned spaceflight program, Project Mercury*an American post-rock band, The Mercury Program...
. The mission of spacecraft # 9 kept changing. It had been first been configured for a suborbital instrumented flight, then for a suborbital chimpanzee flight, then a three-orbit instrumented mission, and finally for the orbital flight that Enos flew.
MA-5 was planned as a close approximation of the upcoming MA-6 manned orbital mission.
Mercury-Atlas 5 would be launched from Complex 14
Cape Canaveral Air Force Station Launch Complex 14
Launch Complex 14 is a launch site at Cape Canaveral Air Force Station, Florida. LC-14 was used for various manned and unmanned Atlas launches, including the Friendship 7 flight aboard which John Glenn became the first American to orbit the Earth....
at Cape Canaveral
Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...
on a heading 72.51 degrees east of north. Orbital insertion of the Mercury spacecraft would occur 480 miles (772.5 km) from Cape Canaveral. The altitude would be 100 miles (160.9 km) and the speed would be 25695 feet per second (7,831.8 m/s). Retrofire was planned to take place at 4 hours, 32 minutes, and 26 seconds after launch. The spacecraft would land 21 minutes and 49 seconds after retrofire. Reentry temperatures were expected to reach 3000 °F (1,648.9 °C) on the heatshield, 2000 °F (1,093.3 °C) on the antenna housing, 1080 °F (582.2 °C) on the cylindrical section, and 1260 °F (682.2 °C) on the conical section. The spent Atlas sustainer engine was expected to reenter the atmosphere after 9⅓ orbits.
On October 29, 1961, three chimps and 12 medical specialists moved into quarters at the Cape to prepare for the flight. The name given to "Enos," the chimp selected to fly the MA-5 mission, in Hebrew
Hebrew language
Hebrew is a Semitic language of the Afroasiatic language family. Culturally, is it considered by Jews and other religious groups as the language of the Jewish people, though other Jewish languages had originated among diaspora Jews, and the Hebrew language is also used by non-Jewish groups, such...
means "man". Enos's backups were (in order possible call-up) Duane, Jim, Rocky and Ham (the MR-2 veteran). Enos was from Cameroon
Cameroon
Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...
, Africa, (originally called Chimp # 81), and was purchased by the USAF on April 3, 1960.
On November 29, 1961, about five hours before launch, Enos and his spacesuit-couch were inserted in the spacecraft. During the countdown
Countdown
A countdown is a sequence of counting backward to indicate the seconds, days, or other time units remaining before an event occurs or a deadline expires. Typical events for which a countdown is used include the launch of a rocket or spacecraft, the detonation of a bomb, the start of a race, and the...
, various holds took 2 hours and 38 minutes. Liftoff
Liftoff
-Plot:Having just been promoted, it's CJ's first day as Chief of Staff. After being introduced to the Secret Service Agents assigned to protect her, it is time for her last press briefing, where she receives a huge round of applause from a stunned Press Room...
came at 15:08 UTC. The Atlas launched the MA-5 spacecraft into an orbit of 99 by.
The turnaround and damping
Damping
In physics, damping is any effect that tends to reduce the amplitude of oscillations in an oscillatory system, particularly the harmonic oscillator.In mechanics, friction is one such damping effect...
maneuver consumed 6 pounds (2.7 kg) of the 61.5 pounds (27.9 kg) of control fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
aboard. The spacecraft used less fuel than the MA-4 did during the same maneuver. MA-5 assumed its planned 34 degree orbital attitude and after that, through the first orbit
Geocentric orbit
A geocentric orbit involves any object orbiting the Earth, such as the Moon or artificial satellites. Currently there are approximately 2,465 artificial satellites orbiting the Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center...
the thrusters
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...
used only 1.5 pound (0.680388555 kg) of fuel to maintain a correct position.
At the end of the first orbit, ground controllers noticed the capsule
Space capsule
A space capsule is an often manned spacecraft which has a simple shape for the main section, without any wings or other features to create lift during atmospheric reentry....
clock was 18 seconds too fast. As it passed over Cape Canaveral a command was sent to update the clock to the correct time. The Mercury Control Center at Cape Canaveral received information that all spacecraft systems were in good condition.
Then as the MA-5 passed over the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
tracking ship at the beginning of the second orbit, indications were received that inverter temperatures were rising. The environmental control system
Environmental Control System
The environmental control system of an aircraft provides air supply, thermal control and cabin pressurization for the crew and passengers...
malfunction was also confirmed by Canary Island trackers. Abnormal heating had occurred on earlier flights; in such cases, inverters had continued working or had been switched to standby. There was no alarm at Mercury Control. When the spacecraft reached Muchea
Muchea Tracking Station
Established in 1960, Muchea Tracking Station was built specifically for NASA's Project Mercury. It was Station No. 8 of 14 sites around the world used throughout the project. The only other Australian site was No...
, Australia, high thruster signals and capsule motion excursions were detected. Other data indicated that the 34 degree orbit mode was being maintained. When the MA-5 crossed the tracking station at Woomera, Australia, attitude control problems were not detected, so earlier reports were discounted.
Problems
As the MA-5 capsule reached the Canton Island station, Mercury Control realized that the attitude control system was malfunctioning. A metal chip in a fuel supply line had caused one of the clockwise roll thrusterThruster
A thruster is a small propulsive device used by spacecraft and watercraft for station keeping, attitude control, in the reaction control system, or long duration low thrust acceleration.-Spacecraft thrusters:...
s to fail. The failed thruster allowed the spacecraft to drift from its normal attitude. This drift caused the automatic stabilization and control system to correct the spacecraft attitude. The spacecraft would swing back into the normal 34 degree orbital attitude, and the sequence would start again. The spacecraft repeated this drift and correction process nine times before retrofire. It did it once more between retrofire and the receipt of the 0.05 g (0.49 m/s²) light telemetry signal. The remaining thrusters used 9.5 pounds (4.3 kg) of fuel to keep the spacecraft properly aligned during the second orbit. Each loss of attitude cost over 1 pound (0.45359237 kg) of fuel as compared with the entire first orbit consumption of only 1.5 pound (0.680388555 kg).
In addition to the attitude control problems, the environmental control system started having problems during the second orbit. The couch-suit circuit temperature rapidly rose from 65 to 80 °F (18 to 26 °C). This was an indication that the heat exchanger was freezing. The rise in suit temperature caused Enos' body temperature to rise to 99 °F (37.2 °C), then to 100 °F (37.8 °C). The medical observers began to worry about the chimp's condition. At 100.5 °F (38.1 °C), his body temperature stabilized. This indicated that the environmental system had started to function again. The cooling system seemed to correct itself, but the attitude problems continued.
As the spacecraft neared Hawaii on its second orbit, medical monitors were willing to let Enos continue the flight for a third orbit. However, engineers were concerned about fuel consumption. They worried that after a third orbit, there would not be enough fuel for attitude control during reentry.
Flight Director Christopher Kraft
Christopher 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...
alerted the Hawaii controllers to be ready to initiate retrofire to bring the spacecraft down in the Pacific, if necessary. He also alerted controllers at Point Arguello
Point Arguello
Point Arguello is a headland used as a launch site by the United States Navy. Point Arguello was first used in 1959 for the launch of military and sounding rockets. It was transferred to the United States Air Force in 1964, at which time it became part of Vandenberg Air Force Base.There were 6...
, California, to be ready to initiate retrofire as MA-5 passed over their position. He allowed the spacecraft to continue to its normal second orbit retrofire position near California. Twelve seconds before the retrofire point was reached for the normal second-orbit Atlantic primary recovery point, Kraft decided to bring Enos back to Earth. The chief flight controller at Point Arguello executed the command.
There was one more attitude control excursion early in reentry; after that, the rest of reentry and recovery were uneventful. The destroyers and and a P5M
P5M Marlin
|- See also :- References :NotesBibliography* Andrade, John, U.S.Military Aircraft Designations and Serials since 1909, Midland Counties Publications, 1979, ISBN 0 904597 22 9.* Barth, Bruce D., "The Martin P5M 'Marlin'". Pacific Aero Press, 1994....
aircraft were waiting for the spacecraft at Station 8, the predicted landing point. Three hours and 13 minutes after launch and nine minutes before splashdown, the aircraft spotted the spacecraft at an altitude of 5000 feet (1,524 m) descending on its main parachute. The information was relayed to the Stormes and the Compton, who were 30 miles (48.3 km) away. The spacecraft recovery aids were all functioning, except for the SARAH beacon. During the descent, the aircraft continued to circle and report landing events. It remained in the area until the Stormes arrived, an hour and 15 minutes after the landing. The Stormes hauled Enos and his spacecraft aboard. On the deck of the Stormes, the MA-5 hatch was blown explosively. It was released from outside the capsule by a pulling a lanyard. Blowing the hatch caused the spacecraft "picture" window to crack.
Post-landing
The spacecraft and Enos were both found to have survived the mission in good condition.On November 4, 1962, Enos died of dysentery caused by shigellosis
Shigellosis
Shigellosis, also known as bacillary dysentery or Marlow Syndrome, in its most severe manifestation, is a foodborne illness caused by infection by bacteria of the genus Shigella. Shigellosis rarely occurs in animals other than humans and other primates like monkeys and chimpanzees...
, which was resistant to antibiotics of the time. He had been under constant observation for two months before his death. Pathologists at Holloman reported that they found no symptom that could be attributed or related to his space flight a year before.
The Mercury spacecraft had now been qualified to carry a human into orbit.
See also
- 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...