Skyhook balloons were high-altitude balloons developed by Otto C. Winzen and General Mills, Inc. They were used by the United States Navy Office of Naval Research (ONR) in the late 1940s and 1950s for atmospheric research, especially for constant-level meteorological observations at very high altitudes. Instruments like the Cherenkov detector were first used on Skyhook balloons.
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 to conduct research. This project carried forward work from an earlier project, Helios, that General Mills and Jean Piccard initiated to use arrays of giant plastic balloons to carry humans aloft. [1]
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. [2] [3] It carried a 63 pounds (29 kg) payload of nuclear emulsion to over 100,000 feet (30,000 m). At low level immediately after launch, the lifting gas (hydrogen or helium) 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 or ovoid. In some models the balloons could reach diameters of more than 30 m. [4]
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, Canada, and naval vessels in the Atlantic, Pacific, Caribbean, and Arctic waters. Both Winzen Research and General Mills participated in these launchings, and in later years, the Atomic Energy Commission joined ONR in support of Project Skyhook. [5]
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, in 1952, featured a Skyhook balloon that released small Deacon rockets at about 70,000 feet (21,000 m) 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. [6] 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. [7]
On September 7, 1956, the University of Minnesota launched a giant Mylar balloon (developed by the G. T. Schejeldahl Corporation of Northfield, MN) to set an unofficial balloon altitude record of 145,000 feet (44,000 m) 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. [5]
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. Instruments included a 12-inch (30-centimeter) telescope with a special light-sensitive pointing system and a closed circuit television camera 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. 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. [8] [9]
In 1948, Skyhook balloons were used to show that in addition to protons and electrons, cosmic rays 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, [10] an Office of Naval Research funded cosmic ray expedition at the geomagnetic equator. 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 90,000 feet (27,000 m) and 105,000 feet (32,000 m) and encountered temperatures as low as -80 °C (-112 °F). 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. [11]
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. [12] (The script of the film Earth vs. the Flying Saucers (1956) mentions "Project Skyhook").
Project Mogul was a top secret project by the US Army Air Forces involving microphones flown on high-altitude balloons, 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. It was a classified portion of an unclassified project by New York University (NYU) atmospheric researchers. 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.
A weather balloon, also known as sounding balloon, is a balloon that 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. To obtain wind data, they can be tracked by radar, radio direction finding, or navigation systems. Balloons meant to stay at a constant altitude for long periods of time are known as transosondes. Weather balloons that do not carry an instrument pack are used to determine upper-level winds and the height of cloud layers. For such balloons, a theodolite or total station is used to track the balloon's azimuth and elevation, which are then converted to estimated wind speed and direction and/or cloud height, as applicable.
Jean Felix Piccard, also known as Jean Piccard, was a Swiss-born American chemist, engineer, professor and high-altitude balloonist. He invented clustered high-altitude balloons, and with his wife Jeannette, the plastic balloon. Piccard's inventions and co-inventions are used in balloon flight, aircraft and spacecraft.
On January 7, 1948, 25-year-old Captain Thomas F. Mantell, a Kentucky Air National Guard pilot, died in the crash of his P-51 Mustang fighter plane near Franklin, Kentucky, United States, after being sent in pursuit of an unidentified flying object (UFO). The event was among the most publicized early UFO incidents.
High-altitude balloons or stratostats are crewed or uncrewed balloons, usually filled with helium or hydrogen, that are released into the stratosphere, generally attaining between 18 and 37 km above sea level. In 2002, a balloon named BU60-1 reached a record altitude of 53.0 km.
Explorer II was a manned U.S. high-altitude balloon that was launched on November 11, 1935, and reached a record altitude of 22,066 m (72,395 ft). Launched at 8:00 am from the Stratobowl in South Dakota, the helium balloon carried a two-man crew consisting of U. S. Army Air Corps Captains Albert W. Stevens and Orvil A. Anderson inside a sealed, spherical cabin. The crew landed safely near White Lake, South Dakota, at 4:13 pm and both were acclaimed as national heroes. Scientific instruments carried on the gondola returned useful information about the stratosphere. The mission was funded by the membership of the National Geographic Society.
The Stratoscopes were two balloon-borne astronomical telescopes which flew from the 1950s to the 1970s and observed in the optical and infrared regions of the spectrum. Both were controlled remotely from the ground.
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.
Lieutenant Commander Victor Alonzo Prather Jr. was an American flight surgeon famous for taking part in "Project RAM", a government project to develop the space suit. On May 4, 1961, Prather drowned during the helicopter transfer after the landing of the Strato-Lab V balloon flight, which set an altitude record for manned balloon flight which stood until 2012.
Malcolm David Ross was a captain in the United States Naval Reserve (USNR), an atmospheric scientist, and a balloonist who set several records for altitude and scientific inquiry, with more than 100 hours flight time in gas balloons by 1961. Along with Lieutenant Commander Victor A. Prather (USN), he set the altitude record for a manned balloon flight.
Project Genetrix, also known as WS-119L, was a United States Air Force program designed to launch General Mills manufactured surveillance balloons over China, Eastern Europe, and the Soviet Union to take aerial photographs and collect intelligence. The Genetrix balloons reached altitudes of 50,000–100,000 feet (15–30 km), well above any contemporary fighter plane.
Project Strato-Lab was a high-altitude manned balloon program sponsored by the United States Navy during the 1950s and early 1960s. The Strato-Lab program lifted the first Americans into the upper reaches of the stratosphere since World War II. Project Strato-Lab developed out of the Navy's unmanned balloon program, Project Skyhook. The program was established in 1954 and administrated by Commander Malcolm Ross. Malcolm Ross and others developed the program to accomplish research required for the manned rocket program to follow. This program provided biomedical data that was used for subsequent efforts in space. Malcolm Ross launched five numbered flights as well as other unnumbered flights.
Winzen Research Inc, Minneapolis, Minnesota, created balloons in the 1950s and 1960s that were used by the United States Navy in its Projects Helios, Skyhook, and Strato-Lab. Balloons were also sold to the United States Air Force for use in Project Manhigh and for a secret reconnaissance mission, called Moby Dick, to overfly the Soviet Union.
The Stratobowl is a compact natural depression within the limits of Black Hills National Forest in South Dakota, south-west of Rapid City. In 1934–1935 it housed a stratospheric balloon launch site, initially known as Stratocamp, sponsored by the National Geographic Society and the United States Army Air Corps. In 1956–1959 the site was reused by the U.S Navy Project Strato-Lab.
An airborne observatory is an airplane, airship, or balloon with an astronomical telescope. By carrying the telescope to a sufficiently high altitude, the telescope can avoid cloud cover, pollution, and carry out observations in the infrared spectrum, above water vapor in the atmosphere which absorbs infrared radiation. Some drawbacks to this approach are the instability of the lifting platform, the weight restrictions on the instrument, the need to safely recover the gear afterward, and the cost compared to a comparable ground-based observatory.
For environmental monitoring, Project Grab Bag was an air sampling program conducted in the United States in the stratosphere of above-ground nuclear weapons testing in the Soviet Union.
A balloon-borne telescope is a type of airborne telescope, a sub-orbital astronomical telescope that is suspended below one or more stratospheric balloons, allowing it to be lifted above the lower, dense part of the Earth's atmosphere. This has the advantage of improving the resolution limit of the telescope at a much lower cost than for a space telescope. It also allows observation of frequency bands that are blocked by the atmosphere.
Edward Purdy Ney was an American physicist who made major contributions to cosmic ray research, atmospheric physics, heliophysics, and infrared astronomy. He was a discoverer of cosmic ray heavy nuclei and of solar proton events. He pioneered the use of high-altitude balloons for scientific investigations and helped to develop procedures and equipment that underlie modern scientific ballooning. He was one of the first researchers to put experiments aboard spacecraft.
Vera Simons (1920–2012) was an inventor, artist, and balloonist. She became known in the 1950s and 1960s as a leader in high altitude gas balloon development and exploration, belonging to a group of pioneers known as the "Pre-Astronauts."
The GUSTO mission is a planned high-altitude balloon mission that will carry an infrared telescope to measure fine-structure line emission from the interstellar medium. The mission is being developed by NASA's Explorers Program for launch in December 2022 from Antarctica.