Soviet space-life scientists Vladimir Yazdovsky and Oleg Gazenko trained the dogs. To adapt the dogs to the confines of the tiny cabin of Sputnik 2, they were kept in progressively smaller cages for periods of up to 20 days. The extensive close confinement caused them to stop urinating or defecating, made them restless, and caused their general condition to deteriorate. Laxatives did not improve their condition, and the researchers found that only long periods of training proved effective. The dogs were placed in centrifuges that simulated the acceleration of a rocket launch and were placed in machines that simulated the noises of the spacecraft. This caused their pulses to double and their blood pressure to increase by 30–65 torr. The dogs were trained to eat a special high-nutrition gel that would be their food in space. Before the launch, one of the mission scientists took Laika home to play with his children. In a book chronicling the story of Soviet space medicine, Dr. Vladimir Yazdovsky wrote, "Laika was quiet and charming ... I wanted to do something nice for her: She had so little time left to live." Vladimir Yazdovsky made the final selection of dogs and their designated roles. Laika was to be the "flight dog"—a sacrifice to science on a one-way mission to space. Albina, who had already flown twice on a high-altitude test rocket, was to act as Laika's backup. The third dog, Mushka, was a "control dog"—she was to stay on the ground and be used to test instrumentation and life support. Before leaving for the Baikonur Cosmodrome, Yazdovsky and Gazenko conducted surgery on the dogs, routing the cables from the transmitters to the sensors that would measure breathing, pulse, and blood pressure. Because the existing airstrip at Turatam near the cosmodrome was small, the dogs and crew had to be first flown aboard a Tu-104 plane to Tashkent. From there, a smaller and lighter Il-14 plane took them to Turatam. Training of dogs continued upon arrival; one after another they were placed in the capsules to get familiar with the feeding system. According to a NASA document, Laika was placed in the capsule of the satellite on 31 October 1957—three days before the start of the mission. At that time of year, the temperatures at the launch site were extremely cold, and a hose connected to a heater was used to keep her container warm.