Venus Statistics
General Venus Geology
GLY 424/524
March 18, 2002
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Mass = 80% Earth’s mass
Uncompressed density = 5250 kg/m3
Equatorial radius = 6052 km
Orbital period = 225 days
Rotational period = 243 (backwards)
Gravity = 8.82 m/s2
Mean surface temp = 482°C
Mean surface pressure = 92 bars
Mariner 2
• First successful Venus flyby
• December 1962/January 1963
• Objectives
– Atmosphere, magnetic field, charged particle
environment, mass
• Results
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Retrograde rotation
Hot, high-pressure surface
CO2 atmosphere
Permanent clouds
No magnetic field
Venera 7
• Venus Lander
• August, 1970
• Returned signals for 23 minutes from
surface before failing
• First transmission from another planet!
• Results
– High surface temperature
– High surface pressure
Venera 4
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Soviet mission
October, 1967
Atmospheric probe
Penetrated to ~25 km above surface
– Atmosphere hot
– High pressure
Venera 8
• June, 1972
• Probe and lander
• Returned signals for 53 minutes after
landing
– Confirmed high surface temps, pressures
– Determined natural light suitable for
photography
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Mariner 10
Venus
Mariner 10
• Slingshot around Venus to reach Mercury
• February, 1974
• Confirmed opaque clouds, “chevron”
pattern suggesting high-altitude winds
Venera 9 Results
Venera 9
• Orbiter and Lander
• October, 1975
• Survived for 53 minutes after landing
• Clouds 30-40 km thick with bases at 30-35
km altitude
• Atmospheric constituents including HCl,
HF, Br, and I
• Surface pressure about 90 (Earth)
atmospheres
• Surface temperature 485°C
• Light levels comparable to those at earth on
a cloudy summer day
• TV photography showing no apparent dust
in the air, and fresh 30-40 cm rocks
Venera 9 landing site
Venera10
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Lander and orbiter
October, 1975
Roughly similar results as Venera 9
Max windspeed of 3.5 m/s
Only image returned
Horizon in corners
Lander pad at center base
Rocks 30-40 cm across
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Venera 11, 12
Pioneer Venus 1 and 2
• Low resolution radar mapping of portions of
Venus
• Orbiters and multiprobes
• Revealed apparently young, tectonically
complex surface
• September, 1978
• Orbiter and Landers
• Instruments
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gas chromatograph
scattered solar radiation
soil composition
amospheric electrical discharges
• Results
– lightning and thunder
– highAr36/Ar40 ratio
– discovery of carbon monoxide at low altitudes
Venera 13 & 14
• March 1982
• Orbiters and Landers
• Instruments
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camera system
X-ray fluorescence spectrometer
screw drill and surface sampler
Dynamic penetrometer
seismometer
Venera 13 Lander
Venera 13 & 14 Results
• Landed near Pheobe Regio
• Images returned
• XRF suggest weakly differentiated
melanocratic alkaline gabbroids
Venera 13 Lander:
Opposite views
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Venera 14 Lander: Opposite
Views
Magellan
• August, 1990
• Near-global coverage in radar ~12.5 cm
wavelength
• Results
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No plate tectonics
85% covered with volcanics
Anhydrous
Winds slow but effective
General Geology
Magellan Topography
• 2 crustal provinces
– Plains
• Presumably volcanic
• Various degrees of deformation
• Low-lying
– Tesserae
• Russian parquet wooden floors
• Formed from plains or older bits of crust poking
through?
• Topographically above plains
Synthetic Aperture Radar
Magellan
Radar image
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Alpha
Regio
Ishtar Terra
Strike-slip
Fault in
Ovda Regio
Venera 13
Landing
Site
Fractured Plains
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Eastern Aphrodite Terra
Coronae
Large Coronae
Stages in Coronae Evolution
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