The Bulletin of the Atomic Scientists has made a 1975 article on the Trinity tests of the atom bombs during the Manhatten Project temporarily available online: A foul and awesome display by Kenneth Bainbridge Bulletin of the Atomic Scientists May 1975 (*.pdf file). Bainbridge was in charge of the first test.
This is a reminder of how things can go wrong:
In the middle of May , on two separate nights in one week, the Air Force mistook the Trinity base for their illuminated target. One bomb fell on the barracks building which housed the carpentry shop, another hit the stables, and a small fire started. Fortunately the barracks occupied by soldiers and civilian scientists were not struck. If the lead plane hit the generator or wires and doused the target lights, then the succeeding planes looked for another illuminated area. This must have been what happened in May of 1945. After all, the crews had come at least a thousand miles to pass their final exam and had probably never been told of anything except targets in the area.
Bainridge writes, "Early in July, Oppenheimer had told me of the approaching meeting beginning July 15, of Truman, Churchill and Stalin. A successful test was a card which Truman had to have in his hand." And he quotes from another report:
The schedule for the test was such that as soon as the plutonium for the bomb was ready, everything else should be ready and the test would be held. There was a little delay but not much. Instructions from Washington were that no day was to be lost and it wasn’t. The nuclear assemblyand final explosives were completed a t Alamogordo and the shot was scheduled for July 16. (R. F. Bacher, “Robert Oppenheimer,” Proceedings of the American Philosophical Society, 116 (1972), 219.)
One of the uncertainties before the first test explosion was the possibility that the atomic blast might ignite the earth's atmosphere and spread for who-knows-how-far:
I had been in the test area nearly all day. Back at the Base I was furious to hear of discussions of the possibility that the atmosphere might be detonated. This possibility had been discussed a t Los Alamos and had been quashed by intensive studies of all possibilitiesby Hans Bethe and others. It was thoughtless bravado to bring up the subject as a table and barracks topic before soldiers unacquainted with nuclear physics and with the results of Bethe’s studies.
The idea of runaway nuclear energy was not new. In 1903 Rutherford had quipped, “Some fool in a laboratory might blow up the universe unawares.”
And the test worked:
The bomb detonated at T = 0 = 5:29:45 a.m. I felt the heat on the back of my neck, disturbingly warm. Much more light was emitted by the bomb than predicted, the only important prediction which was off by a good factor. When the reflected tiare died down, I looked at Oscuro Peak which was nearer Zero. When the reflected light diminished there I looked directly at the ball of fire through the goggles. Finally I could remove the goggles and watch the ball of fire rise rapidly. It was surrounded by a huge cloud of transparent purplish air produced in part by the radiations from the bomb and its fission products. No one who saw it could forgetit, a foul and awesome display.
I had a feeling of exhilaration that the “gadget” had gone off properly followed by one of deep relief. I wouldn’t have to go to the tower to see what had gone wrong. I wouldn’t worry any longer: Had everything been properly anticipated? Was there one lousy soldered joint which had separated for some reason? Had some important circuit grounded because of the rain? Had someone in the final hours of activity, handicapped by fatigue, gotten careless and made the wrong connection or substituted a dummy unit used in rehearsals for the proper final unit?
After turning on the lights, I returned to my car and drove to S 10,000, arriving about 500 a.m. The next step was to broadcast the wind velocity and elevation data to Compagna Hills, N and W 10,000. With the weather the way it was, only the higher After the blast wave had passed, I got up from the ground to congratulate Oppenheimer and others on the success of the implosion method. I finished by saying to Robert, “Now we are all sons of bitches.” Years later he recalled my words and wrote me, “We do not have to explain them to anyone.” I think that I will always respect his statement, although there have been some imaginative people who somehow can’t or won’t put the statement in context and get the whole interpretation.Oppenheimer told my younger daughter in 1966 that it was the best thing anyone said after the test.