The first Soviet missile was the R-1, a duplicate of the V-2 completely manufactured in Russia, which was first launched in October 1948. From 1947 until the end of 1950, the German team elaborated concepts and improvements for extended payload and range under the projects G-1, G-2 and G-4. The German team had to remain on Gorodomlya island until as late as 1952 and 1953. In parallel, Soviet work was focused on larger missiles, the R-2 and R-5, based on further developing the V-2 technology with using ideas of the German concept studies. Details of Soviet achievements were unknown to the German team and completely underestimated by Western intelligence until, in November 1957, the Sputnik 1 satellite was successfully launched to orbit by the Sputnik rocket based on R-7, the world's first intercontinental ballistic missile.