In 1963, cosmonaut training was conducted in six Groups, with Komarov being selected in Group 2 with Valery Bykovsky and Volynov. This group was to train for missions of up to five days in duration scheduled for the latter part of 1963. In May 1963 Alekseyev proposed to General Kamanin that Komarov be named backup for Vostok 5 rather than Khrunov because his suit was ready. Komarov was later named in a further group for planned missions in 1964 with Belyaev, Shonin, Khrunov, Zaikin, Gorbatko, Volynov, and Leonov. The training groups were formed for later Vostok missions (Vostok 7–13), but no actual crews were assigned and the missions did not occur under the auspices of the original Vostok program. In December 1963, Komarov was shortlisted for flight by Kamanin with Volynov and Leonov, having completed two years of training.