Desert Rock was the code name of a series of exercises conducted by the US military in conjunction with atmospheric nuclear tests. They were carried out at the Nevada Proving Grounds between 1951 and 1957. Their purpose was to train troops and gain knowledge of military maneuvers and operations on the nuclear battlefield. They included observer programs, tactical maneuvers, and damage effects tests. From 16 July 1945 through 1946, about 1,000 military and civilian personnel took part in Project TRINITY or visited the test site. All participants, civilian as well as military, were under the authority of the MED. Project activities included scientific studies. Military exercises were not conducted at TRINITY.
Before the detonation, civilian and military scientists and technicians, assisted by other military personnel, placed gauges, detectors, and other instruments around ground zero. An evacuation detachment consisting of 144 to 160 enlisted men and officers was established in case protective measures or evacuation of civilians living offsite became necessary. Such action was not deemed necessary, however, and the evacuation detachment was dismissed late on the day of the detonation for return to Los Alamos.A substantial amount of activity took place at the test site during the first 3 days following the detonation, as scientists entered the ground zero area to retrieve instruments or to perform experiments.