Skyhook balloon

Skyhook balloons were high-altitude balloons developed by Otto C. Winzen (1917–79) 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.

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 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.

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.

...
Wikipedia