Prior to putting an astronaut in orbit, NASA launches a chimpanzee named Enos on a two-orbit Mercury flight to validate the survivability of the spacecraft for an extended flight. Enos is recalled to Earth when both his spacesuit and his Mercury capsule begins heating up unexpectedly, and attitude control is lost; after three hours and two orbits, Mercury 5 returns to Earth. While hauling the capsule from the ocean, recovery crews accidentally crack the window. Despite all this, Enos is safely returned home; he dies a year later from an illness not related to his orbital flight.
