A device designed by Livermore Laboratory was fired at 500-foot altitude above Yucca Lake at 4:45 a.m., Wednsday, June 5. This was the first use of an anchored balloon as a detonation platform.

This is a very experimental device with a very low planned yield.

G.W. Johnson, Test Director, reported that the nuclear detonation was quite successful from the technical viewpoint.

Observers at the Control Point, 15 miles from Ground Zero, saw the detonation as a brief flash followed after some seconds by the appearance of a small cloud above the skyline. The cloud rose eventually above 6,000 feet and was drifting slowly to slightly north of east. It is not anticipated that there will be any reports of fallout, even at the nearby Groom Mine which reportedly was reoccupied yesterday.

Observers heard only a muffled report.

There were some 45 diagnostic and effects experiments on the sequence timer. Additionally, there were 16 military effects experiments. Eighteen aircraft had been scheduled to participate.

The next pre-shot meeting with the press is scheduled for Sunday, June 9, with regard to a balloon shot now scheduled to be ready Monday, June 10.