Vega 1 was launch on December 21, 1984. It was sent to Venus to study the atmosphere and surface. The lander studied the atmosphere as it descended and the surface. The two balloons were deployed on the dark side and stayed in the zone that is most Earth-like. This spacecraft was part of the Halley Armada. It left Venus to have the encounter to get measurements of the comet and its nucleus. Afterwards, it measured dust from other comets.
urn:nasa:pds:context:investigation:mission.vega_2
1.1