Before man stepped foot into space, his best friend came first: dogs. It wasn't a vacation for these pups, though, as they were shipped in outer space as guinea pigs for the Soviets, who were locked in an intense race to the skies against the Americans.

According to a report from Phys Org, the Soviets sent more than 20 dogs into outer space between the 1950s and 1960s. Both NASA and the Soviets conducted animal testing throughout the decade, with subjects that included fruit flies, mice, hamsters, guinea pigs, cats, dogs, frogs, goldfish and monkeys.

The Soviets believed dogs were the ideal test subjects due to their ease with long periods of inactivity. A report from Blastr also revealed that canines' trainability was a plus. In particular, females and strays were considered to better tolerate the stresses. Many of these test subjects never made it back to Earth alive, but these puppy pioneers should be celebrated as among the heroes who paved the way for modern space travel.

Laika is one of the most beloved canine astronauts; a stray from Russia who was chosen as the maiden dog passenger of Sputnik 2 in November 1957. The obedient and good-natured dog tragically died within the first five to seven hours of the flight. Initial word was that she died painlessly due to lack of oxygen, but more recent evidence suggests the cause was more likely overheating and panic because of technical issues related to the botched deployment. It was acknowledged decades later that there were no plans to bring her home at all.

Before Laika's trip was Dezik and Tsygan, who successfully made it to suborbit (110 kilometers into the sky) in 1951. Dezik died on her next flight, which crashed its landing, but Tsygan was adopted by physicist Anatoli Blagonravov.

Belka and Strelka both got happy endings as well after a joint mission on Sputnik 5 in 1960. Along with the doggie pair were a host of other animals: a rabbit, 42 mice, two rats, flies and plants. All spent a full day in orbit and returned back to the planet alive.

One amazing story was the survival of the dogs Comet and Shutka, who were in the voyage of Vostok in December 1960. The module with the dogs broke away from the rocket, sending them catapulting down to Earth and landing in the freezing Siberian wilderness - and the pair somehow survived.