Training the dogs for the satellite flight lasted almost a year. From a dozen very similar dogs, Albina, Laika, and Mukha were chosen. Albina had already been to space twice and already had some cute puppies.

After lengthy discussions, it was decided to send the dog Laika (2 years old, weighing 6 kg) on ​​the flight. Albina was designated as a backup, and Mukha was designated as a test dog, used to test all the measuring equipment and life support systems in the cabin.