Vega 1

A combined mission to Venus and Halley's comet. The whole spacecraft flew to Venus, the mothership got a gravity assist and flew on to Halley's comet while the Venus portion, consisting of a lander and a balloon, entered Venus's atmosphere. The two modules separated midflight and the lander went on to the surface while the balloon was inflated and reached a stable altitude between 53 and 54km. Due to excessive turbulence, some of the surface instruments were accidentally activated while still 20km above the surface. The comet portion flew through the dust tail of the comet and took hundreds of pictures of the nucleus with various filters.