Project Mogul
Encyclopedia
Project Mogul was a top secret
project by the US Army Air Forces
involving microphones flown on high altitude balloon
s, whose primary purpose was long-distance detection of sound waves generated by Soviet
atomic bomb tests
. The project was carried out from 1947 until early 1949. The project was moderately successful, but was very expensive and was superseded by a network of seismic detectors and air sampling for fallout which were cheaper, more reliable, and easier to deploy and operate.
Project Mogul was conceived by Dr. Maurice Ewing
who had earlier researched the deep sound channel in the oceans and theorized that a similar sound channel existed in the upper atmosphere
: a certain height where the air pressure and temperature result in minimal speed of sound, so that sound waves would propagate and stay in that channel due to refraction
. The project involved arrays of balloons carrying disc microphones and radio transmitters to relay the signals to the ground. It was supervised by Dr. James Peoples, who was assisted by Dr. Albert P. Crary
.
One of the requirements of the balloons was that they maintain a relatively constant altitude over a prolonged period of time. (See aerostat
.) Thus instrumentation had to be developed to maintain such constant altitudes, such as pressure sensors controlling the release of ballast
.
The early Mogul balloons consisted of large clusters of rubber meteorological balloons
. However, these were quickly replaced by enormous balloons made of polyethylene
plastic. These were more durable, leaked less helium
, and also were better at maintaining a constant altitude than the early rubber balloons. Constant altitude control and polyethylene balloons were the two major innovations of Project Mogul.
Project Mogul was the forerunner of the Skyhook balloon
program, which started in the late 1940s, as well as another espionage
program involving overflights and photo-surveillance of the Soviet Union in the early 1950s, called Project Moby Dick. The latter raised storms of protest from the Soviets. The balloons were also used for cosmic ray
experiments.
In 1994/5, the Air Force
published a report which concluded that Mogul Flight #4, launched from Alamogordo, New Mexico
, on June 4, 1947, was what crashed near Roswell, New Mexico
, and formed the source of the debris which sparked the Roswell UFO Incident
.
Classified information
Classified information is sensitive information to which access is restricted by law or regulation to particular groups of persons. A formal security clearance is required to handle classified documents or access classified data. The clearance process requires a satisfactory background investigation...
project by the US Army Air Forces
United States Army Air Forces
The United States Army Air Forces was the military aviation arm of the United States of America during and immediately after World War II, and the direct predecessor of the United States Air Force....
involving microphones flown on high altitude balloon
High altitude balloon
High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen that are released into the stratosphere, generally reaching between ....
s, whose primary purpose was long-distance detection of sound waves generated by 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....
atomic bomb tests
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...
. The project was carried out from 1947 until early 1949. The project was moderately successful, but was very expensive and was superseded by a network of seismic detectors and air sampling for fallout which were cheaper, more reliable, and easier to deploy and operate.
Maurice Ewing
William Maurice "Doc" Ewing was an American geophysicist and oceanographer.Ewing has been described as a pioneering geophysicist who worked on the research of seismic reflection and refraction in ocean basins, ocean bottom photography, submarine sound transmission , deep sea coring of the ocean...
who had earlier researched the deep sound channel in the oceans and theorized that a similar sound channel existed in the upper atmosphere
Earth's atmosphere
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
: a certain height where the air pressure and temperature result in minimal speed of sound, so that sound waves would propagate and stay in that channel due to refraction
Refraction
Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed...
. The project involved arrays of balloons carrying disc microphones and radio transmitters to relay the signals to the ground. It was supervised by Dr. James Peoples, who was assisted by Dr. Albert P. Crary
Albert P. Crary
Albert Paddock Crary , was a pioneer polar geophysicist and glaciologist. He made it to the North and then to the South Pole on February 12, 1961 as the leader of a team of eight. The south pole expedition had set out from McMurdo Station on December 10, 1960, using three Snowcats with trailers...
.
One of the requirements of the balloons was that they maintain a relatively constant altitude over a prolonged period of time. (See aerostat
Aerostat
An aerostat is a craft that remains aloft primarily through the use of buoyant lighter than air gases, which impart lift to a vehicle with nearly the same overall density as air. Aerostats include free balloons, airships, and moored balloons...
.) Thus instrumentation had to be developed to maintain such constant altitudes, such as pressure sensors controlling the release of ballast
Buoyancy compensator (aviation)
The static buoyancy of airships during a trip is not constant. It is therefore necessary to take measures to control the buoyancy and thus the altitude, the so-called buoyancy compensation.-Changes which have an effect on buoyancy:...
.
The early Mogul balloons consisted of large clusters of rubber meteorological balloons
Weather balloon
A weather or sounding balloon is a balloon which carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde...
. However, these were quickly replaced by enormous balloons made of polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
plastic. These were more durable, leaked less helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
, and also were better at maintaining a constant altitude than the early rubber balloons. Constant altitude control and polyethylene balloons were the two major innovations of Project Mogul.
Project Mogul was the forerunner of the Skyhook balloon
Skyhook balloon
Skyhook balloons were balloons developed by Otto C. Winzen and General Mills, Inc., and used by the United States Navy Office of Naval Research in the late 1940s and in the 1950s for atmospheric research, especially for constant-level meteorological observations at very high altitudes...
program, which started in the late 1940s, as well as another espionage
Espionage
Espionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, lest the legitimate holder of the information change plans or take other countermeasures once it...
program involving overflights and photo-surveillance of the Soviet Union in the early 1950s, called Project Moby Dick. The latter raised storms of protest from the Soviets. The balloons were also used for cosmic ray
Cosmic ray
Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...
experiments.
In 1994/5, the Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
published a report which concluded that Mogul Flight #4, launched from Alamogordo, New Mexico
Alamogordo, New Mexico
Alamogordo is the county seat of Otero County and a city in south-central New Mexico, United States. A desert community lying in the Tularosa Basin, it is bordered on the east by the Sacramento Mountains. It is the nearest city to Holloman Air Force Base. The population was 35,582 as of the 2000...
, on June 4, 1947, was what crashed near Roswell, New Mexico
Roswell, New Mexico
Roswell is a city in and the county seat of Chaves County in the southeastern quarter of the state of New Mexico, United States. The population was 48,366 at the 2010 census. It is a center for irrigation farming, dairying, ranching, manufacturing, distribution, and petroleum production. It is also...
, and formed the source of the debris which sparked the Roswell UFO Incident
Roswell UFO incident
The Roswell UFO Incident was the recovery of an object that crashed in the general vicinity of Roswell, New Mexico, in June or July 1947, allegedly an extra-terrestrial spacecraft and its alien occupants. Since the late 1970s the incident has been the subject of intense controversy and of...
.
External links
- Physics lecture video in which Prof. Richard A. MullerRichard A. MullerRichard A. Muller is a noted American professor of physics at the University of California, Berkeley. He is also a faculty senior scientist at the Lawrence Berkeley National Laboratory.-Career:...
gives a detailed explanation of the science of Project Mogul (YoutubeYouTubeYouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos....
)