After finishing secondary school in 1952, he graduated from the Moscow Aviation Institute in 1958 as an aerospace engineer and reported to work at the bureau led by Sergei Korolev.

[3] In May 1964, while working for Korolev, Kubasov became one of a handful of civilian candidates who passed preliminary medical screening for one of the Soviet Voskhod missions.

Two years later, after some relaxation of the existing rules, Kubasov along with Georgy Grechko and Vladislav Volkov, were officially accepted into the newly established civilian cosmonaut corps.

The Vulcan furnace required internal hatches between the orbital and descent modules to be sealed, with the welding performed automatically, overseen by Kubasov.

[4] Following his first mission, Kubasov began training to fly aboard the world's first space station, Salyut 1, along with Georgy Shonin and Pyotr Kolodin.

[4] Fearing the onset of tuberculosis, the entire Soyuz 11 prime crew was grounded and replaced by the backup: Georgy Dobrovolsky, Vladislav Volkov and Viktor Patsayev.

During this project Kubasov told the U.S. President Gerald Ford in a TV linkup, that they got "good space food... some juice, some coffee and a lot of water".