called Bereznyak-Isayev BI-1. Special Design Bureau for Special Engines (OKB-SD) was led by Glushko and focused on developing auxiliary liquid-fueled rocket engines to assist takeoff and climbing of prop aircraft, including the RD-IKhZ, RD-2 and RD-3. In 1944, the RD-1 kHz auxiliary rocket motor was tested in a fast-climb Lavochkin La-7R for protection of the capital from high-altitude Luftwaffe attacks. In 1942 Korolev was transferred to OKB-SD, where he proposed development of the long rang missiles D-1 and D-2. The third design bureau was Plant No 51 (OKB-51), led by Soviet Ukrainian Engineer Vladimir Chelomey, where he created the first Soviet pulsating air jet engine in 1942, independently of similar contemporary developments in Nazi Germany. German influence During World War II Nazi Germany developed rocket technology that was more advanced than the Allies and a race commenced between the Soviet Union and the United States to capture and exploit the technology. Soviet rocket specialist were sent to Germany in 1945 to obtain V-2 rockets and worked with German specialists in Germany and later in the Soviet Union to understand and replicate the rocket technology. The involvement of German scientists and engineers was an essential catalyst to early Soviet efforts. In 1945 and 1946 the use of German expertise was invaluable in reducing the time needed to master the intricacies of the V-2 rocket, establishing production of the R-1 rocket and enable a base for further developments. However, after 1947 the Soviets made very little use of German specialists and their influence on the future Soviet rocket program was marginal. Sputnik and Vostok The Soviet space program was tied to the USSR's Five-Year Plans and from the start was reliant on support from the Soviet military. Although he was "single-mindedly driven by the dream of space travel", Korolev generally kept this a secret while working on military projects—especially, after the Soviet Union's first atomic bomb test in 1949, a missile capable of carrying a nuclear warhead to the United States—as many mocked the idea of launching satellites and crewed spacecraft. Nonetheless, the first Soviet rocket with animals aboard launched in July 1951; the two dogs were recovered alive after reaching 101 km in altitude. Two months ahead of America's first such achievement, this and subsequent flights gave the Soviets valuable experience with space medicine. Because of its global range and large payload of approximately five tons, the reliable R-7 was not