In August and September 1958, the United States conducted three of the most secret nuclear tests in history âEUR" detonating warheads in space to test whether artificial radiation belts could disable Soviet missiles and satellites. This Nimble Ultra omnibus collects seven declassified CIA intelligence documents totaling 150 pages on Operation ARGUS, including technical analyses, intelligence assessments, and a National Intelligence Estimate on Soviet nuclear capabilities. The tests confirmed physicist Nicholas Christofilos's theory that nuclear explosions could create artificial Van Allen belts, but the belts decayed within weeks, proving the concept impractical. The secret held until the New York Times broke the story in March 1959, contributing to the 1963 Partial Nuclear Test Ban Treaty. This edition includes AI-generated scholarly apparatus: historical context, four specialized abstracts, a glossary of 27 terms, and indexes of persons, places, organizations, and technologies.