Whether at a high or low altitude, a balloon could not have escaped the pilot’s eyes. It would also have continued to be seen at Godman Field and other points, through occasional breaks in the clouds. I pointed out these facts to one Air Force officer at the Pentagon. Next day he phoned me: “I figured it out. The timing device went off and the balloon exploded. That’s why the pilot didn’t see it.” “It’s an odd coincidence,” I said, “that it exploded in those five minutes after Mantell’s last report.” “Even so, it’s obviously the answer,” he said. Checking on this angle, I found: 1. No one in the Kentucky area had reported a descending parachute. 2. No cosmic-ray research instrument case or parachute was found in the area. 3. No instruments were returned to the Navy from this region. And _all_ balloons and instruments released at that time were _fully accounted for_. Even if it had been a balloon, it would not explain the _later_ January 7th reports—the simultaneous sightings mentioned by Professor Hynek in the Project “Saucer” report. This includes the thing seen at Lockbourne Air Force Base two hours after Mantell’s death. Obviously, the saucer seen flying at 500 m.p.h. over Lockbourne Field could not have been a balloon. Even if there had been several balloons in this area (and there were not, by official record), they could not have covered the courses reported. In some cases, they would have been flying against the wind, at terrific speed. Then what was the mysterious object? And what killed Mantell? Both the Air Force and the _Post_ articles speculate that Mantell carelessly let himself black out. Since some explanation had to be given, this might seem a good answer. But Mantell was known for coolheaded judgment. As a wartime pilot, he was familiar with signs of anoxia (oxygen starvation). That he knew his tolerance for altitude is proved by his firmly declared intention to abandon the chase at 20,000 feet, since he had no oxygen equipment. Mantell had his altimeter to warn him. From experience, he would recognize the first vague blurring, narrowing of vision, and other signs of anoxia. Despite this, the “blackout” explanation was accepted as plausible by many Americans. While investigating the Mantell case, I talked with several pilots and aeronautical engineers. Several questioned that a P-51 starting a dive from 20,000 feet would have disintegrated so thoroughly. “From thirty thousand feet, yes,” said one engineer. “If the idea was to explain it away, I’d pick a high altitude to start from. But a pilotless plane doesn’t necessarily dive, as you know.