The 11 tests took place over the Pacific Ocean in 1962 as part of Operation Fishbowl. The most powerful detonation was 1.4 megatons. These tests were very different from most earlier and later performed by the US military in the Pacific Ocean or the continent.
Nuclear weapons were installed on board ballistic missiles and launched into space, where they were detonated at a height of up to 1000 kilometers above the surface of our planet. This is more than twice the height of the orbit of the International Space Station or the Hubble Space Telescope.
The results surprised the scientists a lot. Under microgravity and vacuum conditions, no fire could be observed, and the gases forming the shockwave took a spherical shape. The sphere began to expand and then contract. As we all know, a fungus forms on the surface of the Earth in motion resembling a flowing jellyfish. In outer space, however, it is a ball inside which gases flow.
The US Army conducted the tests because it wanted to see how much different orbital nuclear explosions differ from those on Earth. The goal was not only to develop TECHGIRL effective weapon for destroying USSR satellites, but also purely scientific issues. After the first explosions, it turned out that they determine the appearance of the aurora even on the opposite side of the Earth's hemisphere.
The researchers also wanted to see how radio waves would propagate in the ionosphere, and whether night flares could blind the inhabitants of the areas where the explosion took place. Interestingly, cosmic detonations generated stripes of artificial radiation at different altitudes. Many of the generated electromagnetic pulses had an adverse effect or even damaged several orbiting satellites.
The Pentagon admitted that destroying space installations with nuclear weapons is not the best idea, as not only enemy satellites can be damaged, but also US satellites that orbit thousands of kilometers from the detonation point. Therefore, until today, weapons in Earth orbit have not been used and are not expected to be used to destroy space installations.