Before humans actually went into space, one of the prevailing theories of the perils of space flight was that humans might not be able to survive long periods of weightlessness.
American and Russian scientists utilized animals - mainly monkeys, chimps and dogs - in order to test each country's ability to launch a living organism into space and bring it back alive and unharmed.
This article highlights of the history of animals involved in space flight, mostly monkeys, mice, and dogs. Also described are the early attempts with animals in sCreatepace flight, the first chimpanzee in space (Ham), the expansion of species in space (such as an Apollo flight that recorded spiders' attempts to spin webs in space), and other notable history.
Source: NASA
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