Baldwin knew he had a big story, but as a Pulitzer Prize–winning war correspondent, graduate of the U.S. Naval Academy, and savvy observer of all things military, he knew the serious ramifications of revealing such a secret operation, especially before it even happened. He decided he needed some guidance on the scientific aspects of it all, so he confided in his Times colleague, the science reporter Walter Sullivan.

“About the end of June, 1958, [Baldwin] put his head in my office and asked if he could talk to me privately for a few minutes,” Sullivan later wrote in his book-length account of the IGY, Assault on the Unknown. “He had learned, he said, that the United States planned to fire several atomic bombs in space.” Baldwin explained his reluctance about going public too soon. In the meantime, Sullivan suggested consulting a friend of his who was “so centrally involved in the U.S. space program that he would be sure to know of the operation.” That was Richard Porter, chairman of the IGY Panel on Rockets and Satellites. Sullivan was sure that Porter would also “give us his candid personal opinion, rather than merely an official line.”

Porter was “both horrified and amused” when Sullivan told him what he and Baldwin had already uncovered. “I can’t tell you not to print it, but I can say this: If you do, the operation will never take place,” he told the science reporter. To emphasize the point, about an hour later Sullivan got a call from the Pentagon’s Advanced Research Projects Agency (ARPA), imploring him to hold the story. ARPA assured Sullivan that Argus would be officially announced and revealed to the world after it was all over, and that the Times would be informed in advance so it could be the first to break the story. Realizing that they’d obviously struck a very sensitive nerve somewhere within the bowels of the Pentagon, Sullivan and Baldwin agreed to sit on the story until the operation had actually taken place.

By the end of 1958, Operation Argus was long over, the task force disbanded, and the faint, militarily ineffectual orbital radiation belts it had generated now faded from existence. And the dark curtain of secrecy and security cloaking Argus was also beginning to falter, as Baldwin and Sullivan began to feel their exclusive scoop slipping away.

Photos: When we tested nuclear bombs

In October 1958, Nicholas Christofilos presented his idea of creating an artificial radiation belt at the Chicago meeting of the American Physical Society. “The only major point he omitted was the use of an atomic bomb,” Sullivan later complained. Then came the annual meeting of the American Association for the Advancement of Science (AAAS) in Washington, D.C., just after Christmas, which Sullivan duly attended as part of his usual Times science beat. At the meeting came more rumblings of Argus from other quarters, including a paper on “Artificial Modification of the Earth’s Radiation Belt,” which inspired questions from a Newsweek reporter about possible connections with high-altitude nuclear explosions. Sullivan realized that his Newsweek colleague was really asking about Argus, albeit indirectly and perhaps somewhat shooting in the dark.