July 22, 1957


The 10th full scale nuclear shot of the Plumbbob series is known as Kepler, is scheduled to fire at 5:10 a.m. PDT Wednesday from a 500-foot tower in Yucca Flat.

The experimental device to be tested was designed by Los Alamos Scientific Laboratory. Its design yield is in a range spanning one-half nominal.

There will be a light on the tower until minus one minute. The tower is located in Area 4 on a compass bearing of 344 degrees and approximately 13 miles from News Nob.

There will be 35 experiments on the sequence timer. Some 33 aircraft will participate. There will be 10 Civil Effects Test Group experiments, all being continuations of previously announced projects. There will be 10 Military Effects experiments. The U.S. Navy plans to have another blimp in Yucca Flat for a continuation of its blast effects experiments.

In addition to the news observers, there will be a group of Civil Defense observers, and there may be 31 FCDA - invited observers from 10 foreign nations. This group was originally scheduled to observer the Shasta shot (the next open shot in the series) but may observe Kepler instead if it is fired Wednesday, and will observe Kepler if it is postponed Wednesday.

Seven hundred military observers will observe the blast from trenches at a distance of 3,000 yards. The Army Signal Corps will continue its tests of tracking the radioactive cloud with radar and various types of ordnance equipment will be subjected to blast, heat and radiation effects in an ordnance test.

[Press Release: Detonation]