Why did the Soviets send dogs to space and Americans used monkeys?

Researchers did not know how weightlessness in space would affect humans, so they sent animals first.

Dog first and chimpanzee second
In her report published in the American magazine "Atlantic", the writer Marina Corin said that researchers at the Institute of Aviation Medicine in Moscow searched for a stray dog ​​and called it "Zip." They then put the dog inside a capsule attached to a rocket that blasted into space, and eventually the dog returned to Earth intact.

This historic voyage began in September 1951 as the Soviet Union was developing a program to send humans into orbit, and researchers worked to test dogs. In the meantime, the United States was conducting similar biomedical research on primates only, such as monkeys and chimpanzees.

The scientists at the time were ignorant of the human body's reaction to zero gravity, as some doctors believed that basic functions such as swallowing and pumping blood to the heart would be impossible without a constant gravitational force.

"Today we realize that animals and humans can adapt in space," said Bill Pritz, an American veterinarian who worked on chimpanzees that flew into space in the early 1960s.

Dogs .. Why?
Both the Soviet Union and the United States have pursued the same goal: to prove the fact that if animals can live in orbit, humans can live there too. But why did the Soviets use dogs, while the Americans used primate?

In fact, the reason for using dogs is that the streets of Moscow were packed with stray dogs.

As Amy Nelson, a history professor at Virginia Tech University who studied the Soviet space dog program, noted that the USSR has already used dogs in research experiments. For example, at the turn of the 20th century, Ivan Pavlov studied classical conditioning, the reflexive behavior that links stimulation and response, by studying the process of digestion in dogs.

Why chimpanzees?
Finding the monkeys was more difficult, as Pritz explained that they were bringing chimpanzees from the Congo region in Africa, but many of these animals were in poor health when they arrived at the program headquarters at Holman Air Force Base in New Mexico. Of the nine veterinarians, eight chimpanzees were infected with hepatitis, and Britz was the only person who had not been infected.

According to veterinarians and historians, American researchers have chosen primate because of physiological similarities with humans, as well as their intelligence. Researchers tried to teach chimpanzees how to perform simple tasks during the trip to test whether they could remain conscious in weightlessness.

Chimpanzees were trained to move the handles in a certain sequence by lighting the lights. During her short journeys, chimpanzees moved the handles from the start of the journey until her return.

Harsh training
In both countries, animals were subjected to harsh training. Soviet dogs were kept in small containers for several hours to simulate the detention they would experience on space flights. They were subjected to loud noise and were crammed into centrifuges to simulate the maximum difficulty of spaceflight, from launch to landing. In the United States, primates have experienced similar tremors and sounds, as well as training in motor skills.

The Americans used the macaque rhesusi monkeys during their first test flights in 1948, where the first six died of suffocation, explosions in flight or landing shock.

Pritz reported that the chimpanzees, who flew in the early 1960s, were better off and recovered from their successful journey to the outskirts of space. But Pritz explained that they were not linked to space flights.

Leica revolves around the Earth
In 1958, Leica was the first female dog to cross the edges of space and orbit the Earth's orbit, but her heartbeats accelerated three times the normal speed and died in space shortly after the flight, due to the high temperature inside the capsule.

In the 1960s, the Soviet Union stopped sending dogs to space, and the United States stopped the primate use program at the same time except for two squirrel monkeys who joined astronauts aboard the space shuttle in 1985, both of which survived.

In conclusion, the author concluded that nearly 70 years after the Soviet dog survived a normal life on Earth, scientists continue to send animals into space to help them conduct their research instead of humans.

According to NASA, there are some mice on the International Space Station at the moment, orbiting the Earth along with the astronauts on board.