Purpose of the flight and payload description
Seeds of several species of angiosperms were flown to high altitudes in a series of flights with the purpose of determining whether cosmic rays and other radiation might have mutagenic effects that would become evident in their seedlings.
With the exception of those seeds sent up on the second flight (none of which germinated), the seeds from the other experimental lots and the control lots showed approximately the same percentage of germination, and the growth and development of seedlings from them were essentially identical. Exposure to cosmic rays and other radiations, notably to the giant atmospheric showers at around 30,000 ft and to heavy nuclei at 100,000 ft altitude, apparently resulted in no visible phenotypic alterations. Thus, under the conditions of these tests, cosmic rays and other radiations seemed ineffective in producing cytogenetic effects on certain seeds and their seedlings.
Details of the balloon flight
Balloon launched on: 11/18/1947 at 8:35 local
Launch site: Stagg Field, University of Chicago, Illinois, US
Balloon launched by: Chicago University Group
Balloon manufacturer/size/composition: Zero Pressure Balloon
End of flight (L for landing time, W for last contact, otherwise termination time): 11/18/1947 at 16:30 local
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 8 h
Landing site: Payload recovered by fishermen from Lake Erie, near Toronto, Canada