In the early days of space travel, scientists wanted to ensure that animals could survive spaceflight before they attempted to send humans. During these first animal flights, scientists were able to test how a living organism would react to the unique environment of spaceflight—including such factors as cosmic radiation, the high rate of acceleration during the flight, and the effects of reduced gravity, also known as microgravity, on the body's cells and vital organs (e.g., the heart and lungs). The evaluation of animals in space also gave scientists information on how the brain would behave in microgravity.

Dogs Lead the Way

The first animal was launched from the Holloman Air Force Base in New Mexico on June 14, 1949. Albert 2 was a monkey, and he traveled 134 kilometers (83 miles) above Earth in a V-2 rocket. His heart rate, blood pressure, and respiratory rate were analyzed, but he died on...