Army intelligence has recently said that “the matter of ‘Unidentified Aircraft’ or ‘Unidentified Aerial Phenomena,’ otherwise known as ‘Flying Discs,’ ‘Flying Saucers,’ and ‘Balls of Fire,’ is considered top secret by intelligence officers of both the army and the air forces.”24
On February 16, 1949, a secret conference was held at the Los Alamos Scientific Laboratory to discuss green fireballs and flying saucers in general. La Paz was there, as was Edward Teller, the inventor of the fuse for the atomic bomb, and a number of military and scientific personnel. There were no representatives, however, from ATIC’s Project Sign/Grudge—an accurate signifier of how irrelevant ATIC’s project really was. Even then, the air force’s investigation of flying saucers was not the only game in town, nor, it is clear, the most serious. A few matters about the conference are known. La Paz told attendees of Kaplan’s assurance that the green fireballs could not be explained by any secret training exercises. Teller thought the objects might not be solid, but perhaps some kind of electro-optic phenomenon. The panel recommended that the government or military set up a series of stations to photograph and analyze the fireballs. AFOSI in fact sent this recommendation to AMC, which did nothing.25
That month, Project Sign issued a final report on UFOs. Of the 237 UFO cases it contained, forty-eight (or 20 percent) were unexplained, not including an additional 13 percent where the “lack of evidence preclude[d] an explanation.” Many of the explanations themselves were, in Hynek’s words, “force-fits.” Despite the huge unexplained rate, the report concluded that there was too little evidence to prove or disprove an objective existence of flying saucers. It recommended closing the project when the air force determined the sightings did not represent a security threat to the nation. The report conceded that UFOs could
Opinions in the classified world diverged on UFOs. A March 15 CIA memo on UFOs from the Office of Scientific Investigation (OSI) dismissed the idea of UFOs as foreign aircraft, and suggested the possibility that they were misidentifications of other phenomena. On March 25, an FBI memo sent to a large number of offices and officials stated the opposite conclusion, that they were “believed to be man-made missiles rather than natural phenomenon.” The memo also stated that the Soviets had been developing an “unknown type of flying disc” since 1945, although this statement has never been substantiated.27 On March 31, another CIA memorandum on Project Sign and UFOs stated the belief that UFOs “will turn out another ‘sea serpent.’ However, since there is even a remote possibility that they may be interplanetary or foreign aircraft, it is necessary to investigate each sighting.” 28 On April 19, the Air Force Office of Special Investigations at Kirtland AFB sent a list of fireball reports to Air Force Headquarters. The cover letter noted:
The common characteristics of most of the incidents are: (a) green color, sometimes described as greenish white, bright green, yellow green, or blue green; (b) horizontal path, sometimes with minor variations; (c) speed less than that of a meteor but more than any other type of known aircraft; (d) no sound associated with observation; (e) no persistent trail or dust cloud; (f) period of visibility from one to five seconds.29
Although AFOSI wanted to continue investigating the fireballs, it received no cooperation from Air Material Command.
A key UFO sighting of the spring occurred during the launch of a top-secret Skyhook balloon on the morning of April 24, about fifty miles from White Sands. Several well-qualified observers, such as scientists, engineers, and officers, saw a UFO visually and measured its movement with a 25-power theodolite.