Skyhook balloons were

high-altitude balloon High-altitude balloons or stratostats are usually uncrewed balloons typically filled with helium or hydrogen and released into the stratosphere, generally attaining between above sea level. In 2013, a balloon named BS 13-08 reached a record alti ...

s developed by

Otto C. Winzen Otto C. Winzen (1917–1979) was a German-American aeronautics engineer who made significant advances in the materials and construction of high-altitude balloons after World War II. Winzen emigrated to the United States in 1937 and spent time d ...

and General Mills, Inc. They were used by the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

Office of Naval Research The Office of Naval Research (ONR) is an organization within the United States Department of the Navy responsible for the science and technology programs of the U.S. Navy and Marine Corps. Established by Congress in 1946, its mission is to plan ...

(ONR) in the late 1940s and 1950s for

atmospheric An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere ...

research, especially for constant-level meteorological observations at very high altitudes. Instruments like the

Cherenkov detector A Cherenkov detector (pronunciation: /tʃɛrɛnˈkɔv/; Russian: Черенко́в) is a type particle detector designed to detect and identify particles by the Cherenkov Radiation produced when a charged particle travels through the medium of th ...

were first used on Skyhook balloons.

Project Skyhook

In the late 1940s, Project Skyhook was conceived of as a means by which plastic balloons could be used to transmit or send instruments into the

stratosphere The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...

to conduct research. This project carried forward work from an earlier project, Helios, that

General Mills General Mills, Inc. is an American multinational corporation, multinational manufacturer and marketer of branded ultra-processed consumer foods sold through retail stores. Founded on the banks of the Mississippi River at Saint Anthony Falls in ...

and

Jean Piccard Jean Felix Piccard (January 28, 1884 in Basel, Switzerland – January 28, 1963 in Minneapolis, Minnesota), also known as Jean Piccard, was a Swiss-born American chemist, engineer, professor and high-altitude balloonist. He invented cluster ...

initiated to use arrays of giant plastic balloons to carry humans aloft. Balloons, long used for collecting meteorological data, now offered the opportunity of collecting highly specialized information and photographs. The first Skyhook balloon was launched on September 25, 1947. The balloon was developed by the Aeronautical Division of General Mills. It carried a payload of

nuclear emulsion A nuclear emulsion plate is a type of particle detector first used in nuclear and particle physics experiments in the early decades of the 20th century. https://cds.cern.ch/record/1728791/files/vol6-issue5-p083-e.pdf''The Study of Elementary Partic ...

to over . At low level immediately after launch, the lifting gas (

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

) in the balloons formed a small bubble at the top of the envelope, resulting in the balloon having a "limp" look. At the lower air pressure at higher altitudes, the gas expanded and eventually filled the whole envelope forming a

sphere A sphere (from Ancient Greek, Greek , ) is a surface (mathematics), surface analogous to the circle, a curve. In solid geometry, a sphere is the Locus (mathematics), set of points that are all at the same distance from a given point in three ...

ovoid An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas of mathematics (projective geometry, technical drawing, etc.), it is given a more precise definition, which may inc ...

. In some models the balloons could reach diameters of more than . In the succeeding 10 years, over 1,500 Skyhook flights were made for investigations supported by the ONR and for European scientists. These flights were made from locations in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, and naval vessels in the

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

, and

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

waters. Both Winzen Research and

participated in these launchings, and in later years, the Atomic Energy Commission joined ONR in support of Project Skyhook. Among significant flights, Project Skyhook launched the first successful three-balloon cluster in 1948. Then in 1949 the first shipboard Skyhook launch took place. It was followed by nearly 300 shipboard launchings over the next 10 years. The first manned plastic balloon flight under ONR contract took place in 1949. Project

Rockoon A rockoon (from ''rocket'' and ''balloon'') is a sounding rocket that, rather than being lit immediately while still on the ground, is first carried into the upper atmosphere by a gas-filled balloon, then separated from the balloon and ignited. ...

, in 1952, featured a Skyhook balloon that released small Deacon rockets at about above arctic waters. One of the first known attempts to carry out an astrophysical measurement from a plastic balloon occurred under the Skyhook program on June 30, 1954. During the solar eclipse on that date two Skyhook balloons were launched by Winzen Research with camera gondolas employing simple orientating systems. The objective was to photograph the eclipse from high altitude. Varied photographic equipment was carried and aimed at the Sun to obtain full coverage for the total period of totality. On September 7, 1956, the

University of Minnesota The University of Minnesota Twin Cities (historically known as University of Minnesota) is a public university, public Land-grant university, land-grant research university in the Minneapolis–Saint Paul, Twin Cities of Minneapolis and Saint ...

launched a giant

Mylar BoPET (biaxially oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical stability, dimensional stability, transparency reflectivity, an ...

balloon (developed by the G. T. Schejeldahl Corporation of Northfield, MN) to set an unofficial balloon altitude record of for unmanned balloons. In 1957 the US Navy began an operational aerology system known as Transosonde (trans-ocean sounding), consisting of almost daily balloon flights across the Pacific Ocean from

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Project Stratoscope

On August 19, 1957, an unmanned Skyhook balloon lifted the first Project Stratoscope telescope. Project Stratoscope I was a program developed to research the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

. Instruments included a 12-inch (30-centimeter)

telescope A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...

with a special light-sensitive pointing system and a

closed-circuit television camera A closed-circuit television camera is a type of surveillance camera that transmits video signals to a specific set of monitors or video recording devices, rather than broadcasting the video over public airwaves. The term " closed-circuit televis ...

that was guided by the scientists on the ground. This was the first balloon-borne telescope. The telescope took more than 400 photographs of

sunspots Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually affe ...

. These were the sharpest photographs taken of the Sun up to that time. The photographs increased scientists' understanding of the motions observed in the strong magnetic fields of the sunspots.

Project Churchy

In 1948, Skyhook balloons were used to show that in addition to

proton A proton is a stable subatomic particle, symbol , Hydron (chemistry), H+, or 1H+ with a positive electric charge of +1 ''e'' (elementary charge). Its mass is slightly less than the mass of a neutron and approximately times the mass of an e ...

s and

electron The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up qua ...

cosmic ray Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the ...

s also include high energy atomic nuclei that are stripped of their electrons. Thirteen stratospheric plastic Skyhook balloons were launched in September 1953 as part of Project Churchy, an Office of Naval Research funded

expedition at the geomagnetic

equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...

. Project Churchy was conducted at the Galápagos because high-energy cosmic-ray particles can only be collected at the geomagnetic equator without accompanying low-energy particles found at higher latitudes. Balloons carrying scientific instruments rose to between and and encountered temperatures as low as . Aircraft from Patrol Squadron (VP) 45 ‘Pelicans’ took off an hour after the launch of each balloon and visually tracked the balloon until it released its cargo and deflated. The instruments were observed until splashdown, and marked for destroyers to retrieve.

Skyhook as UFO

Skyhook balloons may have been the origin of some UFO observations. The most famous case possibly involving a Skyhook mis-sighting was the

Mantell UFO incident On 7 January 1948, 25-year-old Captain Thomas F. Mantell, a Kentucky Air National Guard pilot, died when the P-51 Mustang fighter plane he was piloting crashed near Franklin, Kentucky, United States, after being sent in pursuit of an unidenti ...

.The First Air Force Pilot to Die Chasing a UFO Was Actually Chasing a Secret Balloon
/ref>

Notes

Bibliography

* Freier, P., Lofgren, E. J., Ney, E. P. and Oppenheimer, H. L. 1948. Evidence for heavy nuclei in the primary cosmic radiation. ''Physical Review'' 74:213-17 * United States Centennial of Flight
Otto C. Winzen
*

External links

''Skeptical Inquiry'' article
- The cold war's classified Skyhook program, a participant's revelations

- Historical recopilation project on the use of stratospheric balloons in the scientific research, the military field and the aerospace activity
Office of Naval Research
{{DEFAULTSORT:Skyhook Balloon Balloons (aeronautics) General Mills Military research of the United States