Atlas missile (model A shown) launching from Pad LC-12.
Fifty years ago, the ICBM tests continued down at the Cape. Both NASA and the US Air Force were conducting tests of the various Atlas configurations. Engineers working with both programs learned much from each other. In the case of this particular launch, the test was meant to simulate what would happen if there were a failure of an atomic fuel core aboard a satellite or warhead, during re-entry. Scientists were especially interested in the dispersal pattern of the pieces as they fell to Earth.
Atlas-E launch sequence from trailer.
The rocket used for the test fifty years ago on July 31 (yes I'm a day ahead here, how strange!) was the Atlas model E. This model featured some new rocket guidance equipment, and was designed to be able to launch from a trailer-launch pad system. Atlas E's would be made operational in squadron use starting in September 1961. The last launch of an Atlas E (reconfigured as an Atlas E/F) would take place in 1995! Atlas E launches would fly from Cape Canaveral pads LC-11 and LC-13.