Laika, the first dog in space, memorialised on a postage stamp

Animal astronauts

Michael Regnier introduces us to the organisms that reached space before us

Far beyond the stratosphere, an altitude of 100 km above the Earth’s surface, is the internationally agreed boundary between our atmosphere and outer space. It’s called the Kármán line, and although a suspiciously round number, it is not entirely arbitrary: Theodore von Kármán calculated that it would be around this height that the air would become too thin for a plane to fly.

In 1961, Yuri Gagarin was the first man to cross the Kármán line, and more than 500 people have followed (space)suit since then. But humans are not the only terrestrial species to have gone into space – and we were certainly not the first.


In the early days of the space race – the competition between the USA’s astronauts and the Soviet Union’s cosmonauts in the 1950s and 1960s – animals were used to test whether it was safe to be blasted off the face of the planet in a tiny capsule perched on the tip of a powerful rocket.

Fruit flies were the first to go, travelling in a capsule named ‘Blossom’. Launched by the Americans on a German V2 rocket they had captured during World War II, Blossom reached an altitude of 108 km in February 1947. The capsule had a parachute, and the flies were recovered alive after landing.

Captured V2s were used to transport many more species into space: mice, hamsters, guinea pigs (of course), cats, dogs, frogs, goldfish and monkeys, not to mention various seeds and moss samples, too.

In space, no one can hear you bark (unless you’re on the radio)

Those early pioneers had a pretty much straight up-and-down experience. The first animal to enter orbit around the Earth was Laika, a Russian dog, in November 1957. It was another coup for the Soviets, whose Sputnik 1 had only a month earlier become the first artificial satellite to orbit Earth. Without any means of getting Sputnik 2 safely out of orbit again, however, Laika was doomed and she died in space.

Within three years, two more Russian dogs were among the first animals to survive a flight into Earth orbit and back. They were on Sputnik 5 along with 40-odd mice, two rats, a rabbit and 15 flasks of fruit flies and plants. As well as being filmed while in orbit, it is said that the dogs, named Belka and Strelka, were heard on the radio barking out of the window at a US satellite as they flew past it.

Have a safe flight

With the space race heating up, it was vital to know whether astronauts would be physically and mentally able to operate their craft in space. In January 1961, the Americans trained a chimpanzee called Han to pull levers inside a Mercury capsule. He performed his tasks in orbit just as well as on the ground, suggesting that spaceflight would be practical for humans, too.

Indeed it was, as Gagarin proved for the Soviets just a few months later, making a 108-minute orbit in Vostok 1 at about 320 km above the Earth.

As humans took over the controls, even walking on the Moon (in 1969), they continued to send animals and plants into space to carry out more sophisticated experiments. Researchers particularly wanted to know how prolonged weightlessness affected the body. Would spending time in microgravity conditions cause health problems?

In 1970, America sent up two bullfrogs on the Orbiting Frog Otolith satellite. While in space, a centrifuge put the frogs through cycles of variable gravitational forces and the responses of their vestibular nerves were measured. The vestibular system, which includes the semicircular canals and structures called otoliths in the inner ear, helps frogs – and humans – keep their balance and avoid motion sickness. The experiment showed that the frogs had got used to weightlessness by the end of their week in orbit.

Chicks in space

Space stations and space shuttles made it ever more practical to do off-Earth experiments. In the 1980s, NASA’s Shuttle Student Involvement Program even allowed schoolchildren to put forward research ideas and see them go into orbit.

One such experiment was on board the shuttle Discovery in March 1989, nearly a decade after a high-school student had first proposed the idea. For the study, nicknamed ‘Chix in Space’ and funded by Kentucky Fried Chicken, 32 hens’ eggs were taken into space for five days during their normal 21-day incubation period. The aim was to see if chicken embryos might grow more efficiently without gravity pulling the yolk towards the bottom of the shell.

Eggs laid just two days before take-off failed to hatch after completing incubation on Earth; eggs laid nine days before the trip were (disappointingly, perhaps) entirely normal. The results suggested that gravity has an essential role in embryo development, but only in the first week or so.

Living it up

Space can be a dangerous place, even after you’ve finished the outbound journey on top of roughly a million gallons of violently exploding rocket fuel. Astronauts have to wear elaborate suits to protect them from the cold, the vacuum, the lack of oxygen, the glare of the Sun, the radiation. But there are other forms of life for which space is less of a threat.

In 2007, as part of a European Space Agency mission, tardigrades (also known as water bears or moss piglets) were exposed for ten days to the effects of open space. Brought back inside the capsule, they were rehydrated and continued with their tiny lives as if nothing had happened.

If life exists elsewhere in the universe, it might turn out to be a bit like the tardigrades. These millimetre-long animals can withstand extreme heat and cold, ultraviolet radiation and deep-sea pressures as well as they tolerate open space.

Timeline of space firsts

Lots of people know the name of the first man on the Moon, but do you know the name of the first rabbit in space? Or which animal was the first to go round the Moon? Or when the first fish swam into space? Find the answers here! (Space is defined as an altitude of 100 km or more.)

  • 1946 (USA) – First organisms in space: seeds (not recovered)
  • 1947 (USA) – First animals in space: fruit flies (survived)
  • 1947 (USA) – First monkey in space: Albert II (died due to parachute failure)
  • 1951 (USSR) – First dogs in space: Tsygan and Dezik (survived)
  • 1957 (USSR) – First animal in Earth orbit: the dog Laika (died in orbit)
  • 1959 (USA) – First monkeys to survive spaceflight: Able, a rhesus monkey, and Baker, a squirrel monkey (survived)
  • 1959 (USSR) – First rabbit in space: Marfusa (survived)
  • 1960 (USSR) – First species to survive Earth orbit: dogs, mice, rats and fruit flies (survived)
  • 1961 (USA) – First chimpanzee in Earth orbit: Enos (survived)
  • 1961 (USSR) – First man in space: Yuri Gagarin (survived)
  • 1963 (USSR) – First woman in space: Valentina Tereshkova (survived)
  • 1968 (USSR) – First animals to orbit the Moon: two tortoises, flies and mealworms (survived)
  • 1969 (USA) – First man on the Moon: Neil Armstrong (survived)
  • 1973 (USA) – First fish in space: two unnamed mummichogs (survived)
  • 1973 (USA) – First spiders in space: house spiders Arabella and Anita (survived)
  • 1991 (USSR) – First Briton in space: Helen Sharman (survived)
  • 1997 (international) – First plants to complete growth cycle from seed to seed in space: super-dwarf wheat on board space station Mir (survived)
  • 2007 (international) – First live birth in space: a Russian cockroach named Nadezhda (33 offspring)
  • 2007 (international) – First unprotected organisms in space: tardigrades (survived)

Lead image:

Laika, the first dog launched into space, memorialised on a stamp from Romania, 1957.

Public domain CC BY


Questions for discussion

  • Was it ethical to send animals into space? Is it right to do it today?
  • What experiment would you like to do in space?
  • Do you think we will ever find life beyond Earth?

About this resource

This resource was first published in ‘Space Biology’ in June 2015.

Physiology, History, Biotechnology and engineering
Space Biology
Education levels:
16–19, Continuing professional development