nuclear electromagnetic pulse (NEMP). Canada Other countries were also involved in early ABM research. A more advanced project was at CARDE in Canada, which researched the main problems of ABM systems. A key problem with any radar system is that the signal is in the form of a cone, which spreads with distance from the transmitter. For long-distance interceptions like ABM systems, the inherent inaccuracy of the radar makes an interception difficult. CARDE considered using a terminal guidance system to address the accuracy concerns, and developed several advanced infrared detectors for this role. They also studied a number of missile airframe designs, a new and much more powerful solid rocket fuel, and numerous systems for testing it all. After a series of drastic budget reductions during the late 1950s the research ended. One offshoot of the project was Gerald Bull's system for inexpensive high-speed testing, consisting of missile airframes shot from a sabot round, which would later be the basis of Project HARP. Another was the CRV7 and Black Brant rockets, which used the new solid rocket fuel. Soviet Union The Soviet military had requested funding for ABM research as early as 1953, but were only given the go-ahead to begin deployment of such a system on 17 August 1956. Their test system, known simply as System A, was based on the V-1000 missile, which was similar to the early US efforts. The first successful test interception was carried out on 24 November 1960, and the first with a live warhead on 4 March 1961. In this test, a dummy warhead was released by a R-12 ballistic missile launched from the Kapustin Yar, and intercepted by a V-1000 launched from Sary-Shagan. The dummy warhead was destroyed by the impact of 16,000 tungsten-carbide spherical impactors 140 seconds after launch, at an altitude of . The V-1000 missile system was nonetheless considered not reliable enough and abandoned in favour of nuclear-armed ABMs. A much larger missile, the Fakel 5V61 (known in the west as Galosh), was developed to carry the larger warhead and carry it much further from the launch site. Further development continued, and the A-35 anti-ballistic missile system, designed to protect Moscow, became operational in 1971. A-35 was designed for exoatmospheric interceptions, and would have been highly susceptible to a well-arranged attack using multiple warheads and radar black-out techniques. A-35 was upgraded during the 1980s to a two-layer system, the