Mission Overview
The Pioneer Venus mission consisted of two components, launched separately: an Orbiter and a Multiprobe.

The Pioneer Venus Orbiter was launched on May 20, 1978, and inserted into an elliptical orbit around Venus on December 4, 1978. The Orbiter was a flat cylinder 2.5 m in diameter and 1.2 m high.

The Pioneer Venus Multiprobe launched on August 8, 1978, and consisted of a bus that carried one large and three small atmospheric probes. The large probe was released on November 16, 1978 and the three small probes on November 20. All four probes entered the Venus atmosphere on December 9, followed by the bus.

Relevance to Astrobiology
The Pioneer Venus project was one of many early NASA missions to the planet Venus. When NASA first began, scientists still wondered about life’s potential on Venus, a planet of similar size to the Earth. After missions visited the planet and returned data about the surface and atmosphere, scientists began to realize that Mars was a better target in our search for past or present life in the Solar System.

However, Venus provided invaluable data about habitability on rocky planets. Scientists were able to compare atmospheric and surface processes on Venus and the Earth, providing them with the chance to perform comparative planetology. What we’ve learned about Venus has helped shape our understanding of what makes the Earth habitable for life as we know it.