Fuze, Proximity, Cutaway

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This object is on display in the Space Science at the Steven F. Udvar-Hazy Center in Chantilly, VA.

Space Science

This proximity fuze is typical of those used in artillery shells in the later stages of World War II. The casing of this Mark 58 fuze has been partly cut away to display the microelectronics in the interior, and classified components have been removed, per the label on the stem. This proximity fuze was donated to NASM by Dr. James Van Allen and the University of Iowa in April, 1993.

The proximity fuzes developed in World War II markedly increased the effectiveness of artillery by triggering the explosion of the shell by its proximity to the target. This was accomplished by including a tiny radar-like radio sender-receiver in the fuze. This device depended, in those days before solid state electronics, on the availability of rugged miniaturized vacuum tubes. In 1942 James Van Allen joined the Applied Physics Laboratory of Johns Hopkins University (APL) where he helped develop the required tubes. In 1955, after he had returned to Iowa, he designed the scientific instrumentation that eventually flew on America's first successful satellite, Explorer 1. The instruments in those early spacecraft had to meet some of the same ruggedness and size requirements as those in proximity fuzes. Their design consequently drew on the knowledge that had been gained from designing the microelectronics for the fuzes. Data obtained from Explorer 1 and later satellites led to the discovery of a zone of intense radiation that surrounds the earth that was later named the Van Allen belt.