found: The Nuclear Weapon Archive, via WWW, Oct. 15, 2018:Operation Argus (Operation Argus; 1958 - South Atlantic. Operation Argus was the only clandestine test series in the 17 year history of atmospheric testing. It was secretly conducted in the South Atlantic, 1100 miles southwest of Capetown, South Africa. Argus consisted of three very high altitude test shots of the W-25 warhead to investigate the effects of nuclear explosions outside of the atmosphere - how the charged particles and radioactive isotopes released would interact with the Earth's magnetic field which could potentially interfere with radar tracking, communications, and the electronics of satellites and ballistic missiles)
found: Historical studies in the natural sciences, Sept. 2012, via JSTOR, viewed Oct. 15, 2018:p. 283 (Operation ARGUS; In 1958 the United States secretly conducted a low-yield, high-atmosphere nuclear weapon effects test in the South Atlantic code-named ARGUS) p. 305 (high-altitude explosions) pp. 317-318 (nuclear explosions; atmospheric nuclear testing)
found: Blades, D.M. A history of U.S. nuclear testing and its influence on nuclear thought, 1945-1963, 2014:p. 73 (high-altitude nuclear explosions)
found: Johnston, W.R. High-altitude nuclear explosions, 2009, via WWW, Oct. 15, 2018(The familiar immediate effects of low-altitude nuclear explosions are flash, blast, and prompt radiation. Effects are significantly different for explosions above most of the atmosphere; From 1958 to 1962, the U.S. and U.S.S.R. conducted over a dozen nuclear tests in the Earth's upper atmosphere or in space--the highest at an altitude of 540 km)
found: Hoerlin, H. United States high-altitude test experiences, 1976:p. 1 (The US high-altitude nuclear explosions of the 1955-1962 period) p. 2 (high-altitude explosions)
found: APPG for Future Generations: Black Sky event, via WWW, Oct. 15, 2018(high atmosphere nuclear explosions)
found: Layton, L. Electromagnetic pulse and its impact on the electric power industry, 2016, via WWW, Oct. 15, 2018:p. 18 (high-altitude nuclear explosions) p. 33 (upper atmosphere nuclear explosion)
found: Global space governance, 2017:p. 291 (upper atmospheric nuclear explosion)