The Pioneer Venus Orbiter, launched into orbit around Venus in 1978 and now the only surviving component of the Pioneer Venus mission, enters the cloudy planet’s dense, toxic atmosphere and disintegrates, its fuel supply too exhausted to keep it in orbit any longer. Originally intended to orbit Venus for only a year, Pioneer Venus has survived, fully functional, for nearly 14 years in Venusian orbit, continuing to study the planet and taking readings not only Venus but such objects as Halley’s Comet.
