The 1st animal sent to the space is a dog named laika.
At a time when space travel was still new, scientists chose to send animals for
experiments on space travel. While the Americans went with monkeys and chimpanzees,
the russians preferred dogs for their experiments, starting off with Laika in 1957.
Laika, a stray dog found on the streets was chosen for their project, with their
reasoning being that strays were more accustomed to living in harsh conditions.
As part of their space acclimatization training, the dogs stayedi n progressively
smaller cages, and were trained to eat only high nutrition gels as food.
Unfortunatunately,Laika died a few hours of the spacecraft being launched, due to
overheating in the capsule as it entered earth. However, due to the sensitivity of
the space program at that time, the newspapers reported its death as being caused
by a lack of oxygen, or by poisoned food before the oxygen ran out.
Despite the cruel conditions which laika endured, at least by modern standards,
her maiden space orbit helped prove that living things could survive a launch into
space and tolerate the effects of weightlessness.
A memmorial was built near the Russian cosmonaut training facility, depicting a
dog standing on top of a rocket.
The animal, launched on a one-way trip on board Sputnik 2 in November 1957, was said to have died painlessly in orbit about a week after blast-off.
Now, it has been revealed she died from overheating and panic just a few hours after the mission started.
The new evidence was presented at the recent World Space Congress in Houston, Texas, US, by Dimitri Malashenkov of the Institute for Biological Problems in Moscow.
Noted space historian Sven Grahn told BBC News Online that the new information was surprising and significant as it ended more than 40 years of speculation about Laika's fate.
Laika's mission on board Sputnik 2 stunned the world. Sputnik 1, the world's first satellite, had been launched less than one month before.
An astonished world witnessed the launch of Sputnik 2 weighing 113 kg (250 lbs) and carrying the first living thing to go into orbit - the dog Laika.
The animal had been a stray wandering the streets of Moscow when she was captured and prepared for a space mission.
Shortly after launch the Soviets said that Laika was not destined to return alive and would die in space. The statement caused outrage to many observers.
Dr Malashenkov has now revealed several new details about Laika's mission, such as her food being in jelly form and that she was chained to prevent her turning around.
There was a carbon dioxide absorbing device in the cabin to prevent the accumulation of this toxic gas, as well as an oxygen generator.
A fan was automatically activated to keep the dog cool when the capsule's temperature exceeded 15 deg Celsius.
According to Dr Malashenkov, a great deal of work had to be done to adapt a group of dogs to the conditions in the tight cabin of Sputnik 2. They were kept in gradually smaller cages for periods up to 15-20 days.
Three dogs were trained for the Sputnik 2 flight: Albina, Laika and Mushka. Albina was the first "backup", having flown twice on a high-altitude rocket. Mushka was used to test instrumentation and life support.
Death in space
Medical sensors placed on Laika indicated that during launch her pulse rate went up by a factor of three above its resting level.
At the start of weightlessness, her pulse rate decreased. It took three times longer than after a centrifuge ride on the ground to return Laika's heartbeat to pre-launch values, an indication of the stress she was suffering.
Dr Malashenkov also revealed how Laika died. Telemetry from the Sputnik 2 capsule showed that the temperature and humidity increased after the start of the mission.
After five to seven hours into the flight, no lifesigns were being received from Laika. By the fourth orbit it was apparent that Laika had died from overheating and stress.
Previously, it has been thought that Laika survived at least four days in space and perhaps even a week when Sputnik's transmitters failed.
Despite surviving for just a few hours, Laika's place in space history is assured and the information she provided proved that a living organism could tolerate a long time in weightlessness and paved the way for humans in space.
Laika's "coffin" circled the Earth 2,570 times and burned up in the Earth's atmosphere on 4 April 1958.