V-2 rockets – pioneering examples of cruise missiles and short-range ballistic missiles respectively – were used to strike British cities. The V-1 flying bomb – a pulsejet-powered cruise missile – and the V-2 rocket, a liquid-fueled ballistic missile, were long-range "retaliatory weapons" (German:) designed for strategic bombing, particularly terror bombing and the aerial bombing of cities, as retaliation for the Allied bombings against German cities. In May 1942, following the relative failure of the Baedeker Raids, the development of flying bombs and rockets to target Britain accelerated. The V-1 flying bomb, which was developed by the Luftwaffe at Peenemünde Army Research Center, was the first of the so-called "Vengeance weapons" series. In July 1943, the V-1 flew and impacted within of its target. Ground-launched V-1s were propelled up a 49-m (160 ft)-long, inclined launch ramp consisting of eight modular sections long and a muzzle brake, to enable the missile to become airborne with an airflow strong enough to allow the pulse-jet engine to operate. The steam catapult accelerated the V-1 to a launch speed of , well above the minimum operational speed of . Its operational range was about 200 km (150 mi) and its maximum speed was about 640 km/h (400 mph). The V-2 rocket, with the technical name Aggregat 4 (A-4) – the world's first long-range guided ballistic missile – was developed by Wernher von Braun. The first successful test flight of a V-2 rocket took place on October 3, 1942; it reached an altitude of . The missile was powered by a liquid-propellant rocket engine and used a 75% ethanol/25% water mixture for fuel and liquid oxygen for oxidizer. The fuel and oxidizer pumps were driven by a steam turbine, and the steam was produced using concentrated hydrogen peroxide with sodium permanganate as a catalyst. At launch, the V-2 rocket propelled itself for up to 65 seconds and a programmed motor held the inclination at the specified angle until engine shutdown, after which the rocket continued on a ballistic free-fall trajectory. The rocket reached a height of 80 km (50 mi) after shutting off the engine. Unlike the V-1, the V-2's speed and trajectory made it practically invulnerable to anti-aircraft guns and fighters as it dropped from an altitude of at approximately – up to three times the speed of sound at sea level. Its operational range was about 320 km (200 mi). On May 26, 1943,