Moneron Island
On 23 March 1983 Ronald Reagan publicly announced development of the Strategic Defense Initiative. The Soviet government felt that the purpose of SDI technology was to render the US invulnerable to Soviet attack, thereby allowing the US to launch missiles against the USSR without fear of retaliation. This concern about a surprise attack prompted the sudden expansion of the RYAN program. The level of concern reached its peak after the Soviets shot down KAL 007 near Moneron Island on 1 September 1983, and during the North Atlantic Treaty Organisation exercise Able Archer 83. The Soviet Union believed that a United States first strike on the Soviet Union was imminent.