Well kiddo, you know how people like to explore space and learn more about it? Even before people went to space themselves, they sent animals to space to see how it would affect them. In the 1950s and 1960s, the Soviet Union was sending dogs to space to test how they would react to being weightless and being inside a spaceship.
The Soviet Union chose dogs because they're smart and trainable, and they often become attached to their owners, just like how we love our pets. The dogs that were chosen were trained to sit in small, cramped spaces and to withstand all kinds of conditions that they might experience in space.
One dog named Laika was the first living creature ever sent to orbit the Earth. She was sent up in Sputnik 2 in 1957. Laika was a bit of a celebrity, but unfortunately, she didn't make it back home because the technology to bring her back wasn't developed yet. Her death sparked a lot of controversy, and it was a sad reminder that space exploration can be dangerous for animals and people.
After Laika's tragic mission, other Soviet dogs were sent up into space but with capsules that allowed them to return to Earth safely. These dogs didn't fly around the Earth as Laika had, but instead were launched up into space and quickly returned back to Earth.
In total, the Soviet Union sent about 20 dogs to space, and many of them became heroes of the Soviet space program. These brave dogs helped show humans what is possible and paved the way for humans to explore space safely.