Two flashes detected by a US satellite in 1979 over the southern Indian Ocean — almost certainly a covert Israeli-South African nuclear test. Officially still classified as inconclusive.
The Vela incident was an atmospheric nuclear explosion that occurred on 22 September 1979, near the South African territory of Prince Edward Islands in the Indian Ocean, roughly midway between Africa and Antarctica. This explosion is widely believed to have been an undeclared test of an Israeli nuclear weapon on the ocean surface, carried out with assistance from South Africa. Initially detected as a double flash of light by an American Vela Hotel satellite, further meteorological satellite, hydroacoustic, and radionuclide data support the event's identification as an atmospheric nuclear explosion.