The first US woman in space, Sally Ride, died from pancreatic cancer at the age of 61.
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American astronomer Clyde Tombaugh discovered Pluto.
The New York Times published Edwin Hubble's discovery that the Andromeda 'nebula' is actually a galaxy.
Alan Shepard became the first American to travel to outer space.
The USSR's Voskhod 1 spacecraft became the first spaceflight with multiple crew members.
Two newly discovered moons orbiting Pluto were named Nix and Hydra.
