High Quality Content by WIKIPEDIA articles! The Vostok-K (Russian: meaning "East"), GRAU index 8K72K was an expendable carrier rocket used by the Soviet Union for thirteen launches between 1960 and 1964, six of which were manned. It was derived from the earlier Vostok-L, however it featured uprated engines to improve performance, and enlarge its payload capacity. It was a member of the R-7 family of rockets.The Vostok-K made its maiden flight on 22 December 1960, three weeks after the retirement of the Vostok-L. The third stage engine failed 425 seconds after launch, and the payload, a Korabl'-Sputnik spacecraft, failed to reach orbit. The spacecraft was recovered after landing, and the two dogs aboard the spacecraft survived the flight.