This has been in contention for a very long time, in Sept.1979 a US satellite detected that there was a flash off the coast of Africa. Ok so there is the background of the actual situation, South Africa had developed a nuclear weapon by this period in time. Both Israel and South Africa were very important allies to each other, not only were both outcasts, they did share an ideological imperative with each other. Apartheid South Africa used the same strategy that Israel used in terms of its nuclear weapons program, nuclear ambiguity. This was the finding of the panel by Jimmy Carter: By the early 90’s South Africa had approx. 10 nuclear devices, and had acquired the Jericho technology from Israel. There is even a controversy as to why South Africa gave up her nuclear weapons, was it because they wanted to assimilate back into the world community, or rather they didn’t want the Blacks to take control of the bomb? The South African story is one of immense interest and intrigue. Apartheid South Africa was bad, but it sure was interesting.
There's some information at this link: http://www.michiganufos.com/alert747.html Some more: http://nuclearweaponarchive.org/Safrica/Vela.html http://www.satobs.org/seesat/Sep-1997/0216.html