The USSR also captured a number of V-2s and staff, letting them stay in Germany for a time. The first work contracts were signed in the middle of 1945. In October 1946 (as part of Operation Osoaviakhim) they were obliged to move to Branch 1 of NII-88 on Gorodomlya Island in Lake Seliger where Helmut Gröttrup headed up a group of 150 engineers. In October 1947, a group of German scientists supported the USSR in launching rebuilt V-2s in Kapustin Yar. The German team was indirectly overseen by Sergei Korolev, the "chief designer" of the Soviet rocketry program.