the Y-Plant was operating, it had not yet produced enough weapons-grade uranium for a device. As has happened in programmes in other nations, the development of the devices had outpaced the production of the fissile material. Atomic Energy Commission officials say that a "cold test" (a test without uranium-235) was planned for August 1977. An Armscor official who was not involved at the time said that the test would have been a fully instrumented underground test, with a dummy core. Its major purpose was to test the logistical plans for an actual detonation. How that test was cancelled has been well publicised. Soviet intelligence detected test preparations and in early August alerted the United States; US intelligence confirmed the existence of the test site with an overflight of a Lockheed SR-71 spy plane. On 28 August, The Washington Post quoted a US official: "I'd say we were 99 percent certain that the construction was preparation for an atomic test." The Soviet and Western governments were convinced that South Africa was preparing for a full-scale nuclear test. During the next two weeks in August, the Western nations pressed South Africa not to test. The French foreign minister warned on 22 August of "grave consequences" for French-South African relations. Although he did not elaborate, his statement implied that France was willing to cancel its contract to provide South Africa with the Koeberg nuclear power reactors. In 1993, Wynand de Villiers said that when the test site was exposed, he ordered its immediate shutdown. The site was abandoned and the holes sealed. One of the shafts was temporarily reopened in 1988 in preparation for another test, which did not take place; the move was intended to strengthen South Africa's bargaining position during negotiations to end the war with Angola and Cuba. Viable delivery The warheads were originally configured to be delivered from one of several aircraft types then in service with the South African Air Force (SAAF), including the Canberra B12 and the Hawker Siddeley Buccaneer. Concerns about the vulnerability of the ageing aircraft to the Cuban anti-aircraft defence network in Angola subsequently led the SADF to investigate missile-based delivery systems. The missiles were to be based on the RSA-3 and RSA-4 launchers that had already been built and tested for the South African space programme. According to Al J Venter, author of How South Africa built six atom bombs, these missiles were