Cosmonaut Valentina Tereshkova became the first woman in space.
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The USSR's Voskhod 1 spacecraft became the first spaceflight with multiple crew members.
British astronomer William Lassell discovered Neptune's largest moon, Triton.
Two Earth-like planets in one solar system were discovered.
The first US woman in space, Sally Ride, died from pancreatic cancer at the age of 61.
Astronauts on Apollo 15 discovered a rock that could date back to the birth of the moon.
