The Pioneer Venus Orbiter, also known as Pioneer Venus 1 or Pioneer 12, was a mission to Venus conducted as part of the Pioneer Venus project. Launched in May 1978 atop an Atlas-Centaur rocket, the spacecraft was inserted into an elliptical orbit around Venus on December 4, 1978. It returned data on Venus until October 1992.
The Pioneer Venus Orbiter was launched by an Atlas SLV-3D Centaur-D1AR rocket, which flew from Launch Complex 36A at the Cape Canaveral Air Force Station. The launch occurred at 13:13:00 on May 20, 1978, and deployed the Orbiter into heliocentric orbit for its coast to Venus. Venus orbit insertion occurred on December 4, 1978.
Spacecraft
Manufactured by Hughes Aircraft Company, the Pioneer Venus Orbiter was based on the HS-507 bus. The spacecraft was a flat cylinder, 2.5 meters (8.2 ft) in diameter and 1.2 meters (3.9 ft) long. All instruments and spacecraft subsystems were mounted on the forward end of the cylinder, except the magnetometer, which was at the end of a 4.7 meters (15 ft) boom. A solar array extended around the circumference of the cylinder. A 1.09 metres (3 ft 7 in) despun dish antenna provided S and X band communication with Earth. A Star-24 solid rocket motor was integrated into the spacecraft to provide the thrust to enter orbit around Venus.
From Venus orbit insertion to July 1980, periapsis was held between 142 and 253 kilometres (88 and 157 mi) (at 17 degrees north latitude) to facilitate radar and ionospheric measurements. The spacecraft was in a 24-hour orbit with an apoapsis of 66,900 kilometers (41,600 mi). Thereafter, the periapsis was allowed to rise to a maximum of 2,290 kilometres (1,420 mi) and then fall, to conserve fuel.
In 1991, the Radar Mapper was reactivated to investigate previously inaccessible southern portions of the planet, in conjunction with the recently arrived Magellan spacecraft. In May 1992, Pioneer Venus began the final phase of its mission, in which the periapsis was held between 150 and 250 kilometres (93 and 155 mi), until the spacecraft's propellant was exhausted, after which the orbit decayed naturally. The spacecraft continued to return data until 8 October 1992, with the last signals being received at 19:22 UTC. The Pioneer Venus Orbiter disintegrated upon entering the atmosphere of Venus on October 22, 1992.
Experiments
The Pioneer Venus Orbiter carried 17 experiments with a total mass of 45 kg:
a cloud photo-polarimeter (OCPP) to measure the vertical distribution of the clouds, similar to Pioneer 10 and Pioneer 11 imaging photo-polarimeter (IPP)
a surface radar mapper (ORAD) to determine topography and surface characteristics. Observations could only be conducted when the probe was closer than 4700 km over the planet. A 20 Watt S-band signal (1.757 gigahertz) was sent to the surface that reflected it, with the probe analyzing the echo. Resolution at periapsis was 23 x 7 km.
an infrared radiometer (OIR) to measure IR emissions from Venus' atmosphere
an airglow ultraviolet spectrometer (OUVS) to measure scattered and emitted UV light
a neutral mass spectrometer (ONMS) to determine the composition of the upper atmosphere
a solar windplasma analyzer (OPA) to measure properties of the solar wind
a magnetometer (OMAG) to characterize the magnetic field at Venus
an electric field detector (OEFD) to study the solar wind and its interactions
an electron temperature (OETP) to study the thermal properties of the ionosphere
an ion mass spectrometer (OIMS) to characterize the ionospheric ion population
a charged particle retarding potential analyzer (ORPA) to study ionospheric particles
two radio science experiments to determine the gravity field of Venus
an atmospheric drag experiment to study the upper atmosphere
a radio science atmospheric and solar wind turbulence experiment
a gamma ray burst (OGBD) detector to record gamma ray burst events
The spacecraft conducted radar altimetry observations allowing the first global topographic map of the Venusian surface to be constructed.
Observations of Halley's Comet
From its orbit of Venus, the Pioneer Venus Orbiter was able to observe Halley's Comet when it was unobservable from Earth due to its proximity to the sun during February 1986. UV spectrometer observations monitored the loss of water from the comet's nucleus at perihelion on February 9.
Science Magazine in year 1979 issue 4401
Donahue, T. M. (6 July 1979). "Pioneer Venus Results: An Overview". Science. 205 (4401): 41–44. JSTOR 1748508.
Colin, Lawrence (6 July 1979). "Encounter with Venus: An Update". Science. 205 (4401): 44–46. JSTOR 1748509.
Seiff, Alvin; Kirk, Donn B.; Young, Richard E.; Sommer, Simon C.; Blanchard, Robert C.; Findlay, John T.; Kelly, G. M. (6 July 1979). "Thermal Contrast in the Atmosphere of Venus: Initial Appraisal from Pioneer Venus Probe Data". Science. 205 (4401): 46–49. JSTOR 1748510.
Hoffman, J. H.; Hodges, R. R.; McElroy, M. B.; Donahue, T. M.; Kolpin, M. (6 July 1979). "Composition and Structure of the Venus Atmosphere: Results from Pioneer Venus". Science. 205 (4401): 49–52. JSTOR 1748511. PMID 17778898.
Oyama, V. I.; Carle, G. C.; Woeller, F.; Pollack, J. B. (6 July 1979). "Laboratory Corroboration of the Pioneer Venus Gas Chromatograph Analyses". Science. 205 (4401): 52–54. JSTOR 1748512.
Niemann, H. B.; Hartle, R. E.; Hedin, A. E.; Kasprzak, W. T.; Spencer, N. W.; Hunten, D. M.; Carignan, G. R. (6 July 1979). "Venus Upper Atmosphere Neutral Gas Composition: First Observations of the Diurnal Variations". Science. 205 (4401): 54–56. JSTOR 1748513.
Pollack, James B.; Black, David C. (6 July 1979). "Implications of the Gas Compositional Measurements of Pioneer Venus for the Origin of Planetary Atmospheres". Science. 205 (4401): 56–59. JSTOR 1748514.
Stewart, A. Ian; Barth, Charles A. (6 July 1979). "Ultraviolet Night Airglow of Venus". Science. 205 (4401): 59–62. JSTOR 1748515. PMID 17778902.
Keating, G. M.; Taylor, F. W.; Nicholson, J. Y.; Hinson, E. W. (6 July 1979). "Short-Term Cyclic Variations and Diurnal Variations of the Venus Upper Atmosphere". Science. 205 (4401): 62–64. JSTOR 1748516.
Taylor, F. W.; Diner, D. J.; Elson, L. S.; McCleese, D. J.; Martonchik, J. V.; Delderfield, J.; Bradley, S. P.; Schofield, J. T.; Gille, J. C.; Coffey, M. T. (6 July 1979). "Temperature, Cloud Structure, and Dynamics of Venus Middle Atmosphere by Infrared Remote Sensing from Pioneer Orbiter". Science. 205 (4401): 65–67. JSTOR 1748517.
Blamont, Jacques; Ragent, Boris (6 July 1979). "Further Results of the Pioneer Venus Nephelometer Experiment". Science. 205 (4401): 67–70. JSTOR 1748518. PMID 17778905.
Knollenberg, Robert G.; Hunten, D. M. (6 July 1979). "Clouds of Venus: A Preliminary Assessment of Microstructure". Science. 205 (4401): 70–74. JSTOR 1748519.
Travis, L. D.; Coffeen, D. L.; Del Genio, A. D.; Hansen, J. E.; Kawabata, K.; Lacis, A. A.; Lane, W. A.; Limaye, S. S.; Rossow, W. B.; Stone, P. H. (6 July 1979). "Cloud Images from the Pioneer Venus Orbiter". Science. 205 (4401): 74–76. JSTOR 1748520.
Pollack, James B.; Ragent, Boris; Boese, Robert; Tomasko, Martin G.; Blamont, Jacques; Knollenberg, Robert G.; Esposito, Larry W.; Stewart, A. Ian; Travis, Lawrence (6 July 1979). "Nature of the Ultraviolet Absorber in the Venus Clouds: Inferences Based on Pioneer Venus Data". Science. 205 (4401): 76–79. JSTOR 1748521.
Tomasko, Martin G.; Doose, Lyn R.; Smith, Peter H. (6 July 1979). "Absorption of Sunlight in the Atmosphere of Venus". Science. 205 (4401): 80–82. JSTOR 1748522.
Suomi, V. E.; Sromovsky, L. A.; Revercomb, H. E. (6 July 1979). "Preliminary Results of the Pioneer Venus Small Probe Net Flux Radiometer Experiment". Science. 205 (4401): 82–85. JSTOR 1748523.
Counselman, C. C.; Gourevitch, S. A.; King, R. W.; Loriot, G. B.; Prinn, R. G. (6 July 1979). "Venus Winds Are Zonal and Retrograde Below the Clouds". Science. 205 (4401): 85–87. JSTOR 1748524.
Woo, Richard; Armstrong, J. W.; Kendall, William B. (6 July 1979). "Measurements of Turbulence in the Venus Atmosphere Deduced from Pioneer Venus Multiprobe Radio Scintillations". Science. 205 (4401): 87–89. JSTOR 1748525.
Pettengill, Gordon H.; Ford, Peter G.; Brown, Walter E.; Kaula, William M.; Masursky, Harold; Eliason, Eric; McGill, George E. (6 July 1979). "Venus: Preliminary Topographic and Surface Imaging Results from the Pioneer Orbiter". Science. 205 (4401): 90–93. JSTOR 1748526.
Phillips, Roger J.; Sjogren, William L.; Abbott, Elsa A.; Smith, John C.; Wimberly, Ray N.; Wagner, Cari A. (6 July 1979). "Gravity Field of Venus: A Preliminary Analysis". Science. 205 (4401): 93–96. JSTOR 1748527.
Taylor, Harry A.; Brinton, Henry C.; Bauer, Siegfried J.; Hartle, Richard E.; Cloutier, Paul A.; Daniell, Robert E.; Donahue, Thomas M. (6 July 1979). "Ionosphere of Venus: First Observations of Day-Night Variations of the Ion Composition". Science. 205 (4401): 96–99. JSTOR 1748528.
Kliore, A. J.; Patel, I. R.; Nagy, A. F.; Cravens, T. E.; Gombosi, T. I. (6 July 1979). "Initial Observations of the Nightside Ionosphere of Venus from Pioneer Venus Orbiter Radio Occultations". Science. 205 (4401): 99–102. JSTOR 1748529. PMID 17778916.
Brace, L. H.; Theis, R. F.; Niemann, H. B.; Mayr, H. G.; Hoegy, W. R.; Nagy, A. F. (6 July 1979). "Empirical Models of the Electron Temperature and Density in the Nightside Venus Ionosphere". Science. 205 (4401): 102–105. JSTOR 1748530.
Knudsen, W. C.; Spenner, K.; Whitten, R. C.; Spreiter, J. R.; Miller, K. L.; Novak, V. (6 July 1979). "Thermal Structure and Energy Influx to the Day- and Nightside Venus Ionosphere". Science. 205 (4401): 105–107. JSTOR 1748531.
Nagy, A. F.; Cravens, T. E.; Chen, R. H.; Taylor, H. A.; Brace, L. H.; Brinton, H. C. (6 July 1979). "Comparison of Calculated and Measured Ion Densities on the Dayside of Venus". Science. 205 (4401): 107–109. JSTOR 1748532.
Bauer, Siegfried J.; Donahue, Thomas M.; Hartle, Richard E.; Taylor, Harry A. (6 July 1979). "Venus Ionosphere: Photochemical and Thermal Diffusion Control of Ion Composition". Science. 205 (4401): 109–112. JSTOR 1748533.
Taylor, W. W. L.; Scarf, F. L.; Russell, C. T.; Brace, L. H. (6 July 1979). "Absorption of Whistler Mode Waves in the Ionosphere of Venus". Science. 205 (4401): 112–114. JSTOR 1748534.
Russell, C. T.; Elphic, R. C.; Slavin, J. A. (6 July 1979). "Initial Pioneer Venus Magnetic Field Results: Nightside Observations". Science. 205 (4401): 114–116. JSTOR 1748535.
Intriligator, D. S.; Collard, H. R.; Mihalov, J. D.; Whitten, R. C.; Wolfe, J. H. (6 July 1979). "Electron Observations and Ion Flows from the Pioneer Venus Orbiter Plasma Analyzer Experiment". Science. 205 (4401): 116–119. JSTOR 1748536.
Evans, W. D.; Glore, J. P.; Klebesadel, R. W.; Laros, J. G.; Tech, E. R.; Spalding, R. E. (6 July 1979). "Gamma-Ray Burst Observations by Pioneer Venus Orbiter". Science. 205 (4401): 119–121. JSTOR 1748537.
Donahue, T. M. (6 July 1979). "Pioneer Venus Results: An Overview". Science. 205 (4401): 41–44. JSTOR 1748508.
Colin, Lawrence (6 July 1979). "Encounter with Venus: An Update". Science. 205 (4401): 44–46. JSTOR 1748509.
Seiff, Alvin; Kirk, Donn B.; Young, Richard E.; Sommer, Simon C.; Blanchard, Robert C.; Findlay, John T.; Kelly, G. M. (6 July 1979). "Thermal Contrast in the Atmosphere of Venus: Initial Appraisal from Pioneer Venus Probe Data". Science. 205 (4401): 46–49. JSTOR 1748510.
Hoffman, J. H.; Hodges, R. R.; McElroy, M. B.; Donahue, T. M.; Kolpin, M. (6 July 1979). "Composition and Structure of the Venus Atmosphere: Results from Pioneer Venus". Science. 205 (4401): 49–52. JSTOR 1748511. PMID 17778898.
Oyama, V. I.; Carle, G. C.; Woeller, F.; Pollack, J. B. (6 July 1979). "Laboratory Corroboration of the Pioneer Venus Gas Chromatograph Analyses". Science. 205 (4401): 52–54. JSTOR 1748512.
Niemann, H. B.; Hartle, R. E.; Hedin, A. E.; Kasprzak, W. T.; Spencer, N. W.; Hunten, D. M.; Carignan, G. R. (6 July 1979). "Venus Upper Atmosphere Neutral Gas Composition: First Observations of the Diurnal Variations". Science. 205 (4401): 54–56. JSTOR 1748513.
Pollack, James B.; Black, David C. (6 July 1979). "Implications of the Gas Compositional Measurements of Pioneer Venus for the Origin of Planetary Atmospheres". Science. 205 (4401): 56–59. JSTOR 1748514.
Stewart, A. Ian; Barth, Charles A. (6 July 1979). "Ultraviolet Night Airglow of Venus". Science. 205 (4401): 59–62. JSTOR 1748515. PMID 17778902.
Keating, G. M.; Taylor, F. W.; Nicholson, J. Y.; Hinson, E. W. (6 July 1979). "Short-Term Cyclic Variations and Diurnal Variations of the Venus Upper Atmosphere". Science. 205 (4401): 62–64. JSTOR 1748516.
Taylor, F. W.; Diner, D. J.; Elson, L. S.; McCleese, D. J.; Martonchik, J. V.; Delderfield, J.; Bradley, S. P.; Schofield, J. T.; Gille, J. C.; Coffey, M. T. (6 July 1979). "Temperature, Cloud Structure, and Dynamics of Venus Middle Atmosphere by Infrared Remote Sensing from Pioneer Orbiter". Science. 205 (4401): 65–67. JSTOR 1748517.
Blamont, Jacques; Ragent, Boris (6 July 1979). "Further Results of the Pioneer Venus Nephelometer Experiment". Science. 205 (4401): 67–70. JSTOR 1748518. PMID 17778905.
Knollenberg, Robert G.; Hunten, D. M. (6 July 1979). "Clouds of Venus: A Preliminary Assessment of Microstructure". Science. 205 (4401): 70–74. JSTOR 1748519.
Travis, L. D.; Coffeen, D. L.; Del Genio, A. D.; Hansen, J. E.; Kawabata, K.; Lacis, A. A.; Lane, W. A.; Limaye, S. S.; Rossow, W. B.; Stone, P. H. (6 July 1979). "Cloud Images from the Pioneer Venus Orbiter". Science. 205 (4401): 74–76. JSTOR 1748520.
Pollack, James B.; Ragent, Boris; Boese, Robert; Tomasko, Martin G.; Blamont, Jacques; Knollenberg, Robert G.; Esposito, Larry W.; Stewart, A. Ian; Travis, Lawrence (6 July 1979). "Nature of the Ultraviolet Absorber in the Venus Clouds: Inferences Based on Pioneer Venus Data". Science. 205 (4401): 76–79. JSTOR 1748521.
Tomasko, Martin G.; Doose, Lyn R.; Smith, Peter H. (6 July 1979). "Absorption of Sunlight in the Atmosphere of Venus". Science. 205 (4401): 80–82. JSTOR 1748522.
Suomi, V. E.; Sromovsky, L. A.; Revercomb, H. E. (6 July 1979). "Preliminary Results of the Pioneer Venus Small Probe Net Flux Radiometer Experiment". Science. 205 (4401): 82–85. JSTOR 1748523.
Counselman, C. C.; Gourevitch, S. A.; King, R. W.; Loriot, G. B.; Prinn, R. G. (6 July 1979). "Venus Winds Are Zonal and Retrograde Below the Clouds". Science. 205 (4401): 85–87. JSTOR 1748524.
Woo, Richard; Armstrong, J. W.; Kendall, William B. (6 July 1979). "Measurements of Turbulence in the Venus Atmosphere Deduced from Pioneer Venus Multiprobe Radio Scintillations". Science. 205 (4401): 87–89. JSTOR 1748525.
Pettengill, Gordon H.; Ford, Peter G.; Brown, Walter E.; Kaula, William M.; Masursky, Harold; Eliason, Eric; McGill, George E. (6 July 1979). "Venus: Preliminary Topographic and Surface Imaging Results from the Pioneer Orbiter". Science. 205 (4401): 90–93. JSTOR 1748526.
Phillips, Roger J.; Sjogren, William L.; Abbott, Elsa A.; Smith, John C.; Wimberly, Ray N.; Wagner, Cari A. (6 July 1979). "Gravity Field of Venus: A Preliminary Analysis". Science. 205 (4401): 93–96. JSTOR 1748527.
Taylor, Harry A.; Brinton, Henry C.; Bauer, Siegfried J.; Hartle, Richard E.; Cloutier, Paul A.; Daniell, Robert E.; Donahue, Thomas M. (6 July 1979). "Ionosphere of Venus: First Observations of Day-Night Variations of the Ion Composition". Science. 205 (4401): 96–99. JSTOR 1748528.
Kliore, A. J.; Patel, I. R.; Nagy, A. F.; Cravens, T. E.; Gombosi, T. I. (6 July 1979). "Initial Observations of the Nightside Ionosphere of Venus from Pioneer Venus Orbiter Radio Occultations". Science. 205 (4401): 99–102. JSTOR 1748529. PMID 17778916.
Brace, L. H.; Theis, R. F.; Niemann, H. B.; Mayr, H. G.; Hoegy, W. R.; Nagy, A. F. (6 July 1979). "Empirical Models of the Electron Temperature and Density in the Nightside Venus Ionosphere". Science. 205 (4401): 102–105. JSTOR 1748530.
Knudsen, W. C.; Spenner, K.; Whitten, R. C.; Spreiter, J. R.; Miller, K. L.; Novak, V. (6 July 1979). "Thermal Structure and Energy Influx to the Day- and Nightside Venus Ionosphere". Science. 205 (4401): 105–107. JSTOR 1748531.
Nagy, A. F.; Cravens, T. E.; Chen, R. H.; Taylor, H. A.; Brace, L. H.; Brinton, H. C. (6 July 1979). "Comparison of Calculated and Measured Ion Densities on the Dayside of Venus". Science. 205 (4401): 107–109. JSTOR 1748532.
Bauer, Siegfried J.; Donahue, Thomas M.; Hartle, Richard E.; Taylor, Harry A. (6 July 1979). "Venus Ionosphere: Photochemical and Thermal Diffusion Control of Ion Composition". Science. 205 (4401): 109–112. JSTOR 1748533.
Taylor, W. W. L.; Scarf, F. L.; Russell, C. T.; Brace, L. H. (6 July 1979). "Absorption of Whistler Mode Waves in the Ionosphere of Venus". Science. 205 (4401): 112–114. JSTOR 1748534.
Russell, C. T.; Elphic, R. C.; Slavin, J. A. (6 July 1979). "Initial Pioneer Venus Magnetic Field Results: Nightside Observations". Science. 205 (4401): 114–116. JSTOR 1748535.
Intriligator, D. S.; Collard, H. R.; Mihalov, J. D.; Whitten, R. C.; Wolfe, J. H. (6 July 1979). "Electron Observations and Ion Flows from the Pioneer Venus Orbiter Plasma Analyzer Experiment". Science. 205 (4401): 116–119. JSTOR 1748536.
Evans, W. D.; Glore, J. P.; Klebesadel, R. W.; Laros, J. G.; Tech, E. R.; Spalding, R. E. (6 July 1979). "Gamma-Ray Burst Observations by Pioneer Venus Orbiter". Science. 205 (4401): 119–121. JSTOR 1748537.
