Laika in training.
A recycled post from 2007
Beginning in the early 1950s, small female stray dogs were gathered from the streets of Moscow and taken to a nearby Russian research center for experiments in suborbital space flight. Dogs were chosen for these experiments because they were cheap and scientists felt they would be able to endure long periods of inactivity better than most other animals.
Females were chosen because they did not have to stand and lift a leg to urinate. The female dogs used in the "space race" experiments were trained to stay still for long periods of time (they spent 15-20 days at a time in small boxes) and wear such pieces of clothing as a pressurized suit and helmet.
From 1951 through 1952, nine unnamed dogs successfully flew suborbitally in R-1 series rockets. Three of these dogs flew two missions each.
A dog named "Laika" was launched into space in Sputnik 2 on November 3, 1957. Laika, whose real name was Kudryavka (Little Curly), is often described as a "huskie-mix" but pictures show a small dog that looks very much like a fox terrier. The fact that Laika weighed only 13 pounds supports a fox terrier taxonomy -- even the smallest of huskies would weight much more. American newspapers of the time called her "Muttnik".
Laika was the first living creature ever to be launched into earth orbit, and Laika was the only animal Russian scientists knowingly sent into space to die. At the time there was no recovery method for true orbital flights.
At the World Space Congress in Houston in November of 2003, Dimitri Malashenkov of the Institute for Biological problems in Moscow finally revealed what happened to Laika. According to Malashenkov, medical sensors recorded that immediately after the launch, Laika's capsule reached speeds of nearly 18,000 miles per hour. As the pressure in the capsule increased, Laika's pulse rate increased to three times its normal level, presumably due to overheating, fear and stress. Five to seven hours into the flight, no further life signs were received from the dog.
Sputnik 2 fell back to earth on April 14, 1958 -- four and a half months after leaving earth -- and burned up on re-entry.
In 1998, 79-year-old Oleg Gazenko, one of the lead scientists on the Soviet animals-in-space program, expressed his deep regrets during a Moscow news conference: "The more time passes, the more I'm sorry about it. We shouldn't have done it.... We did not learn enough from this mission to justify the death of the dog."