Hipparcos satellite

The Hipparcos satellite was a European Space Agency mission launched in 1989 to measure the positions and distances of over a million stars with unprecedented accuracy. By using parallax, the apparent movement of stars against distant background stars, Hipparcos determined how far away these stars are from Earth. This data helped astronomers create detailed three-dimensional maps of the Milky Way, improving our understanding of stellar formation, motion, and the structure of our galaxy. The mission's significant contributions have enhanced both astrometry, the study of star positions, and our knowledge of the cosmos.