Class 13: Venus Overview
Venus and Earth: Twins?
Similarities
• Size (radius)
• Bulk density
• Tectonism, volcanism
Venus
6051.9 km
5.2 g/cm 3
yes (today?)
Earth
6378 km
5.5 g/cm 3
yes (today)
Differences
• Rotation
• Atmosphere
• Surface pressure
• Surface temperature
• Plate tectonics
• Water
-243 days
97% CO 2
90 atm
455°C
no
DRY!
1 day
78% N 2, 21% O2
1 atm
20°C
yes
yes
Composition & Atmosphere
crust
atmosphere
mantle
core
1
Rotation & Orbit
3
4
2
10
5
1
Earth
9
Venus
direct
retrograde
6
8
7
Exploration of Venus
•
16 missions
Venera
1961-1983
USSR
(9 landers, 3 probes, 4 orbiters)
•
Mariner 2,5,10 Flyby
1962, 1967, 1973-75
US
•
Pioneer Venus Orbiter/Probes
1978-1992
US
•
Vega 1, 2
Venus flyby
1985
USSR
•
Magellan
Mapping Mission
1989-1994
US
•
Galileo
Flyby
1990
US
Mariner 10
Pioneer Venus
Galileo
Hubble
Venera Landers
Venera 4
Venera 7
failed (<25 km)
T s = 720 K
Ps = 90 atm
•
Venera 9, 10
Venera 13, 14
1 Photograph
Photographs
•
Venera 13,14,18
•
Venera 14, 18
•
•
•
Ur, Tr, K
drilled samples
& X-ray analyses
Venera Lander
2
Venera: View of the Surface
Venera 13
1983
Venera 14
Magellan Mission
(1989 - 1994)
global mapping
Magellan
Spacecraft
Magellan before launch
Kennedy Space Center
3
Magellan Mapping of Venus
Radar Imaging
1
2
surface
type
flat
surface
forest
cropland mountains rough city
surface
Radar
Image
Example: Radar Image
4
Stuff about Radar Images
flat
surface
sloping
surface
rough
surface
Example: Radar Image
Resolution & Topography
Height above mean
5
Magellan Gravity Data
Magellan-measured Gravity
milligal
s
Venus: Important Processes
Impact craters
Shield volcanoes
Pancake domes
6