Halley's Comet is the most famous periodic comet, returning to the inner Solar System every 76 years on a retrograde, highly inclined orbit. Recorded observations stretch back to 240 BC, and its 1986 apparition was visited by an international armada of spacecraft. On 1 January 2025 it is outbound beyond Neptune, coasting toward aphelion near 35 AU before its next perihelion in 2061. Its orbit sweeps through the planetary zone alongside Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Halley is the prototype of Jupiter-family comets — bodies whose orbits were shortened by repeated encounters with the giant planet.