9 July 1962. At Johnston Atoll, a scrap of coral in a remote part of the Pacific, a Thor IRBM stands on the pad as launch preparations are carried out. Loaded with test equipment, its prime payload is a W-49/Mk-4 RV payload. The target, however, is not to be found on a map or chart.
Instead, today’s launch is part of the DOMINIC series of atmospheric nuclear tests. These tests were ordered following the re-start of Soviet atmospheric testing, most notable of which was the test of the Царь-бомба (lit: “tsar bomba“), the largest nuclear explosion to date.
The test today is one of some 36 planned tests under DOMINIC. Most of these, like Housatonic, were air-dropped weapons (Housatonic had a yield of ~8Mt). Some were tests of complete weapons systems – like Swordfish and Frigate Bird (the former a test of the nuclear ASROC and the latter, the only complete test of a US ICBM with a nuclear warhead — an operational shot of the Polaris I SLBM). The Thor on the pad today is supporting Starfish Prime – a high altitude nuclear detonation to test the effects of a phenomena identified as EMP, Electromagnetic Pulse. The phenomena s not unexpected as it was noticed in conventional high explosives, but tests in the late 1950s that involved high altitude, endo-atmospheric tests had witnessed an unusual number of test equipment failures due to overvoltage effects. The launch tonight, with zero-hour scheduled for 0900Z/2300L Hawaii time, is targeted for an altitude of 248 miles, the very upper limits of the atmosphere. The mission is not without hazard as an earlier attempt on 20 June suffered an engine failure on launch and was command destroyed – on the pad. While the warhead didn’t detonate, the subsequent scattering of plutonium almost forced the shutdown of the Johnston facility. But the launch tonight worked and at zero-hour, the skies over Oahu, 800 nm away, became bright as day and in the south, a large, white orb slowly rose out of the ocean while in the high atmosphere, the night glowed, bathed in the light of the man-made aurora:
More importantly, on the island of Oahu, the electromagnetic pulse created by the explosion was felt as three hundred street lights failed, television sets and radios malfunctioned and burglar alarms were triggered. On Kauai, the EMP shut down telephone calls to the other islands by burning out the equipment used in a microwave link. Over the next few days, seven satellites that transited the radiation belts that were created in low earth orbit subsequently failed. Among these were the (then) new and first of its kind, commercial relay satellite, Telstar. Eventually one-third of the satellites in low earth orbit failed or were substantially degraded.
But that wasn’t the worst of it. The Soviets conducted their own test whose effects were devastating. At the height of the Cuban Missile crisis, a demonstration of the ABM system was conducted wherein a 300kt device was detonated at a 290-km altitude near Dzhezkazgan. Prompt gamma ray-produced EMP induced a current of 2,500 amps in a 570-km stretch of overhead telephone lines to Zharyq, blowing all the protective fuses. The late-time MHD-EMP was of low enough frequency to enable it to penetrate up to 90 cm into the ground, overloading a shallow buried lead and steel tape-protected 1,000-km long power cable between Aqmola and Almaty, firing circuit breakers and setting the Karaganda power plant on fire (Glasstone). The atmospheric tests ceased soon thereafter, but not the research or planning on EMP effects. Indeed, as we moved into the 1970s and 80′s, and serious talk of nuclear warfighting was underway on both sides of the iron curtain, we worked to test and harden our weapons and platforms to EMP:
But the Cold War is over, we’re engaged in the prelude for a new round of nuclear reduction talks with Russia so the threat must be diminishing and there is nothing to fear…right?
(to be continued)