Purpose of the flight and payload description
This apparatus was the first attempt of the U.S. Atomic Energy Comission (AEC) to develope a sampling system for use on balloons. Following the "Sunshine" Rand study, that theorized that a significant part of the radioactive debris from a high-yield nuclear detonation would be injected in the stratosphere during years before returning to ground, the New York Operations Office of the AEC undertook to quickly built an electrostatic precipitator to collect stratospheric particulate debris for strontium-90 analysis. From December 1953 to July 1954 with the cooperation of the US Air Force, these samplers (which can be seen in the image at left) were flown successfully many times over Holloman Air Force Base at altitudes between 80.000 and 100.000 ft.
A set back of the system was the collection efficiency of the precipitator was not known in advance for the voltages used in the collector system, which were set safely below the breakdown voltage for such low ambient pressures (about 1/100 atmosphere). In later laboratory tests, the efficiency turned out to be about 17% under simulated flight conditions. Combined with the relatively low air flow rate through the precipitator, this did not provided large enough samples for radiochemical analysis. However, relative concentrations of total beta activity were recorded during the series, and a large rise of stratospheric radioactivity over New Mexico was measured in mid-April, that is about six weeks after the Castle-Bravo explosion, the first US test of a dry fuel hydrogen bomb in the Pacific. The flights were discontinued in July 1954.
Details of the balloon flight
Balloon launched on: 7/7/1954
Launch site: Holloman Air Force Base, Alamogordo, New Mexico, US
Balloon launched by: Balloon Branch, Holloman Air Force Base (HAFB)
Balloon manufacturer/size/composition: Zero Pressure Balloon Winzen - 83.3 foot Diam. (2.0 Mil)
Flight identification number: HAFB 239
End of flight (L for landing time, W for last contact, otherwise termination time): 7/7/1954
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 8 h 25 m
Landing site: 6 miles E of Tombstone, Arizona, US
Payload weight: 160 lbs
Overall weight: 384 lbs