Pioneer Venus
A comprehensive investigation of Venus' atmosphere
The Pioneer Venus orbiter was the first of a two-spacecraft orbiter-probe combination designed to conduct a comprehensive investigation of the atmosphere of Venus. Pioneer measured the detailed structure of the upper atmosphere and ionosphere of Venus, investigated the interaction of the solar wind with the ionosphere and the magnetic field in the vicinity of Venus, determined the characteristics of the atmosphere and surface of Venus on a planetary scale, determined the planet’s gravitational field harmonics from perturbations of the spacecraft orbit, detected gamma-ray bursts, and made UV observations of comets.
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Launch date: May 20, 1978
End Dates: End of Comet Mission: February 4, 1986; End of Venus Mission: October 8, 1992
Mission duration: 15 years
Lead Institution: Goddard Space Flight Center
Partners: NASA Ames Research Center
Ultraviolet Spectrometer (OUVS)
This investigation used a 125 mm Cassegrain telescope on a 125 mm Ebert-Fastie spectrometer with a programmable grating drive. Airglow, scattered sunlight, and hydrogen Lyman-alpha emissions were detected in the thermosphere, mesosphere, and exosphere of Venus. These measurements were used to establish and map the composition, temperature, and photochemistry of the thermosphere and ionosphere, to determine the pressure at and above the visible cloud tops, and to establish the distribution and escape rate of atomic hydrogen.