But no sooner had it been switched on, alarm bells started to clang as the system immediately went to High Alert. A missile launch had been detected. Reasoning the Soviets wouldn’t launch a massive nuclear strike on their own leader, Slemon called off the alert. On that tense October day, the brand-new, state of the art, $1.2 billion BMEWS system had detected not a swarm of Soviet missiles, but the Moon rising over Norway. Around midnight on the 26th of September, 1983, a Russian Oko early-warning satellite detected a single ballistic missile launch somewhere in the mainland United States, followed soon after by four more.