Hipparcos

Overview

ESA's pioneering astrometry satellite, which precisely measured the positions, distances, and motions of over 100,000 stars — the forerunner of Gaia. An apogee-motor failure left it in a highly elliptical orbit, yet it still delivered landmark astrometric catalogues.

Knowledge connections

• OrbitGeostationary Transfer Orbit (GTO)
• Operated byESA

Sources

The primary and reference sources this topic draws on.

• ESAEuropean Space Agency

  European missions, observatories, and space science imagery.