to defend against MIRV and decoy style weapons.The reason for this was because the detonation of a nuclear interceptor missile like the "Galosh" creates a cloud of plasma that temporarily impairs radar readings around the area of the explosion limiting these kinds of systems to a one-shot capacity. This means that with MIRV style attacks the interceptor would be able to take out one or two but the rest would slip though. Another issue with the 1965 model was that it consisted of 11 large radar stations at six locations on the borders of Russia. These bases where visible to the US and could be taken out easily leaving the defense system useless in a concentrated and coordinated attack. Finally, the missiles that could be held on each base was limited by the ABM treaty to only 100 launchers maximum, meaning that in a massive attack they would be depleted quickly. During installation, a Ministry of Defense commission concluded that the system should not be fully implemented, reducing the capabilities of the completed system. That system was later upgraded to the A-135 anti-ballistic missile system and is still operational. This upgrade period started in 1975 and was headed by Dr. A.G. Basistov. When it was completed in 1990, the new A-135 system had a central control multifunctional radar called the "Don" and 100 interceptor missiles. Another improvement was the layering of interceptor missiles where high acceleration missiles are being added for low flying targets and the "Galosh" style missiles where improved further for high altitude targets. All of these missiles where moved underground into silos to make them less vulnerable, which was a flaw of the previous system. The SALT I talks began in 1969, and led to the Anti-Ballistic Missile Treaty in 1972, which ultimately limited the U.S. and U.S.S.R. to one defensive missile site each, with no more than 100 missiles per site. This included both ABM interceptor missiles as well as launchers. Originally, the agreement made by the Nixon administration and the Soviet Union stated that both of the two nations were each allowed to have two ABM defensive systems present in their own countries. The goal was to effectively have one ABM defense system located near each nation's capital city as well as another ABM defense system placed near the nation's most important or strategical ICBM field. This treaty allowed for an effective form of deterrence