Pioneer Venus consisted of two spacecraft to study Venus: the Orbiter and the Multiprobe. The latter separated into 5 separate vehicles near Venus. The Orbiter was launched on the 20 May 1978 from the Kennedy Space Center aboard an Atlas-Centaur rocket. It went into orbit around Venus on 4 December 1978. Its primary objective was to investigate the solar wind in the Venusian environment, map Venus' surface through a radar imaging system, and study the characteristics of the upper atmosphere and ionosphere. The Orbiter carried twelve instruments, most of them dedicated to plasma investigations of the Venusian upper atmosphere, as well as instruments for observing reflected sunlight from the cloud layers at a variety of wavelengths, and a surface radar mapper. There was, however, a gamma-ray burst detector experiment added on the satellite. Although originally intended to operate in orbit for one Venusian year, most of the Orbiter instruments, including the gamma ray burst detector, were still operating when the spacecraft entered the atmosphere on 8 October 1992.

The Pioneer Venus Multiprobe was launched on 8 August 1978. It encountered Venus on 9 December 1978. It consisted of 5 separate probes: the probe transporter (referred to as the Bus), a large atmospheric entry probe (called Sounder), and 3 identical small probes (called North, Day, and Night). The Sounder released from the Bus on 15 November 1978; the 3 small probes released on 19 November 1978. All probes entered the Venusian atmosphere within 11 minutes of each other, and descended toward the surface over approximately an hour-long period sending data back to Earth.