Sputnik 1 became Earth’s first artificial satellite to go into orbit.
Source
Halley's Comet was last seen from Earth. It only orbits the Earth once every 75 to 76 years.
Alan Shepard became the first American to travel to outer space.
Frederick Langenheim took the first photo of a solar eclipse.
The 51 Pegasi b planet was discovered. It was the first discovered exoplanet around a sun-like star.
Carl Gustav Witt discovered the first near-Earth asteroid, 433 Eros.
