Several theories have suggested possible reasons why the Soviet Union itself might have wanted to destroy one of Chernobyl's nuclear reactors, deliberately causing the disaster. The Chernobyl incident happened during the Cold War between the United States and the Soviet Union, and both superpowers had spent much of the previous four decades trying to advance their own military technologies and develop new weapons and tactics that would give them an edge in a potential confrontation. The purpose of destroying Chernobyl's reactor could have been to further study the effects of radiation and fallout (known areas of interest for the Soviet military) or to test methods of sabotaging American nuclear facilities. The Soviets could also have had political motivations for causing a nuclear meltdown at Chernobyl. Controlling the European energy market was an important factor in keeping other European nations within the Soviet Union's sphere of influence. The Chernobyl disaster discouraged the construction of other nuclear power plants across Europe, thus fostering dependence on Russia's rich fossil fuel resources. Alternatively, destroying Chernobyl could have been a way of covering up the failure of the nearby Duga-3 radio facility. The powerful radio signals originating from Duga-3 starting in 1976 were rumored to be related to Soviet anti-ballistic missile systems or even experiments with radio-based mind control, but the vast size and expense of the facility were a potential embarrassment for its Soviet backers if it failed in its purpose. Chernobyl's destruction distracted from Duga-3 and provided a convenient excuse for its failure, as the proximity of the nuclear disaster to the massive radio facility disrupted its operations.