The A-35 anti-ballistic missile system was a Soviet military anti-ballistic missile (ABM) system deployed around Moscow to intercept enemy ballistic missiles targeting the city or its surrounding areas. The A-35 was the only Soviet ABM system allowed under the 1972 Anti-Ballistic Missile Treaty. In development as of the 1960s and in operation from June 1972 until the 1990s, it featured the nuclear-armed A350 exoatmospheric interceptor missile. The A-35 was supported by two Dunay radars (NATO reporting names: Cat House and Dog House) and the Soviet early warning system. It was followed by the A-135 in the early 1990s. System A The first Soviet anti-ballistic missile system was System A, which began development at Sary Shagan's Test Range A in July 1956, followed by testing starting in 1959. System A used the V-1000 missile to intercept enemy missiles. First launch of the V-1000 took place on 11 October 1957; its first successful intercept occurred on 4 March 1961, when it intercepted an R-12 missile launched from the Kapustin Yar site. System A used the Dunay-2 radar designed by V Sosulnikov at NII-37 (which later became NIIDAR), in addition to three homing radars and an RSV-PR ABM radar (NATO: Hen Nest). The three homing radars (called RTN; NATO name Hen Egg)) were situated in an equilateral triangle with a length of . The system could track missiles from a distance of about . The V-1000 launcher and the ABM radar were located together. The system used an M-40 computer which could perform 40,000 operations per second. A-35 Work on the A-35 system first started in 1959 with a test model called Aldan. The system's designer was Gregory Kisunko of Soviet Experimental Design Bureau OKB-30. A new missile, called the A-350, was to be designed by P. Grushin of OKB-2. Unlike the V-1000, the missile was to have a nuclear warhead. The design of the system called for it to be able to intercept several hostile incoming missiles simultaneously with a single warhead. It was also to intercept them outside the atmosphere. The A-35 was to have a main command centre, eight early warning radars with overlapping sectors, and 32 battle stations. Installation work on the A-35 began in 1965, but by 1967 only the test version at Sary Shagan was ready. Awareness of the system's flaws, including its inability to handle MIRVs, was part of the reason a 1967 Ministry of Defence