Terraforming: Venus
http://fc08.deviantart.net/fs45/i/2009/114/6/3/Terraformed_Venus_by_TheDarkLordOfMordor.png
Steyrleithner
Astrobiology
27.11.2013
Outlook
‣
Venus: Overview
-
Facts
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Missions
-
Surface
-
Atmosphere
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Venus: Terraforming
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Get rid of the dense atmosphere
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Get rid of CO2
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Cooling Venus
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Colonisation of Venus (?)
Facts
Property
Venus
Venus/Earth
4.8685E+24
0.815
6051.8
0.950
6051.8 (6051.8)
0.952 (0.994)
4.6E+8
0.902
Bulk density [kg m-3]
5243
0.951
Average surface temperature [°C]
464
30.93
Average surface pressure [bar]
92
92
Escape velocity [km s-1]
10.36
0.926
Surface gravity [m s-2]
8.87
0.905
Sidereal spin rate [hr]
5832.5
243.686
Spin velocity (at equator) [km s-1]
1.81E-3
3.89E-3
Obliquity [deg]
177.36
7.55
none
-
224.701
0.615
1.0821E+8
0.723
35.02
1.176
Total mass [kg]
Average radius [km]
Polar (Equatorial) radius [km]
Surface area [km2]
Magnetic field [Tesla]
Sidereal (orbital) periode [d]
Average distance from Sun [km]
Average orbital speed [km s-1]
Data from M. Beech, Terraforming
Missions
30
failed
succesful
USSR missions
4
successful
failed
25
3
20
15
2
10
1
5
0
USSR NASA
0
1961 1963 1965 1967 1969 1971 1973 1975 1981 1984
Data from: http://www.planetary.org/explore/space-topics/space-missions/missions-to-venus-mercury.html#planetc
Missions: attempted by the USSR
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Mariner 2: first successful Venus flyby (NASA - 1962)
-
‣
discovered ground-temperature of 428°C
Venera 3: first spacecraft to land (impact) on another planet (USSR - 1965/66)
-
‣
no data returnd!
Venera 4: first successful Venus probe (USSR - 1967)
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descended with a parachute into the atmosphere
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instruments: thermometer, barometer
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found out, that the atmosphere consists almost entirely of CO2
Missions: attempted by the USSR
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Venera 7: successful Venus probe (USSR - 1970)
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descended with a parachute into the atmosphere
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probe had a touch down: fist spacecraft to return data from the surface of another planet
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atmospheric data: T = 475°C, P = 90 bar
Missions: attempted by the USSR
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Venera 9: successful Venus orbiter & lander (USSR - 1975)
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first spacecraft to transmit a picture from another planets surface
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probe got data about the venusian clouds and atmospheric composition
http://nssdc.gsfc.nasa.gov/imgcat/hires/v09_lander.gif
Missions: active/future
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Messenger: active mission (NASA - 2004)
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Venus flyby, no scientific observations → superior cunjunction
Akatsuki: active mission, orbiter (JAXA - 2010)
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aka Venus Climate Orbiter, Planet-C
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cloud and surface imaging with IR-camera, confirm lightnings and volcanic activity
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Venus Express: active mission (ESA - 2005)
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studying the venusian atmosphere and clouds, plasma environments and surface characteristics
BepiColombo: future mission (ESA/JAXA - 2015)
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actually a mission to Mercury
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Venus flyby in 2017/18
Surface
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most information of venusian surface from radar observations
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mainly images from the Magellan probe → mapped 98% of the surface
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there are few impact craters, because of the dense atmosphere
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the surface is relatively flat
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total distance from the highest to the lowest point is ~13 km
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the topography is divided into:
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highlands: ~10% of the surface with an altitude > 2 km
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deposition planes: > 50% of the surface with an altitude between 0 and 2 km
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lowlands: surface below zero altitude
Surface: topography of Venus
http://zebu.uoregon.edu/~soper/ImVenus/topol.gif
Surface: unusual characteristics
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Corona:
-
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formed by upwellings of warm
material below the surface →
mantle plumes
Tessera
-
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https://www.mtholyoke.edu/
courses/mdyar/ast223/
venus_a/tessera.jpg
caused by crust folding,
buckling and breacking
Arachnoid
-
http://upload.wikimedia.org/
wikipedia/commons/1/19/
Fotla_Corona_PIA00202.jpg
concentric ovals surrounded
by complex features
http://www.uni.edu/morgans/
astro/course/Notes/section4/
tick.jpg
Atmosphere
http://upload.wikimedia.org/wikipedia/commons/thumb/6/63/Venusatmosphere.svg/2000px-Venusatmosphere.svg.png
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surface values:
T=467°C, P=93 bar
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clouds with sulfuric acid
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the entire atmosphere rotates in
4 earth days around Venus
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‣
windspeed:
-
upper atmosphere: ~100 m s-1
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at the surface: ~10 m s-1
Ionosphere separates the
atmosphere from outer space
Atmosphere: Composition
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Composed mainly of CO2 and small amounts of N
-
‣
due to the dense venusian atmosphere, the amount of N is 4 times higher than on Earth
Other compounds: CO, O, sulfuric acid, ...
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large amount of H is lost to space. The lost was proved by very high D/H ratio which is
10 times higher than the terrestial value
http://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/AtmosphereofVenus-2.svg/2000px-AtmosphereofVenus-2.svg.png
Terraforming
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It is much more difficult than on Mars
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Requirements for terraforming Venus:
1.
The planet’s atmosphere must be cooled down
2.
The planet’s atmosphere mass must be reduced
3.
Most of the atmospheric CO2 must be removed
4.
Water must be imported to the planet
5.
(The planet’s rotation rate must be increased)
Terraforming: Atmospheric blow-off
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Direct collision:
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use several KBO’s to blow off the atmosphere
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a large bode could eject mass above the tangent
plane (TP), but only a few ten-thousands of the
venusian atmosphere
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need ~103 impacts to get an earth-like atmosphere
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Off-centre collision:
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to spin-up venus (shorter day/night cycle)
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byproduct: small venusian moons (?)
M. Beech, Terraforming
Terraforming: Atmospheric mining
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via a ‘ram scoop’
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a more esthetically solution
M. Beech, Terraforming
Terraforming: Oberg-Fogg process
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Bringing cyanobacteria into the atmosphere
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Simultaneous import of H2
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CO2 is broken down through photosynthesis → producing O2
O + H2 → H2O
mining H2 from Saturn’s atmosphere
Process becomes self-supporting
Terraforming: Oberg-Fogg process
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Carbon accumulates on the surface,
while CO2 gets broken down
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At the end, there will be a ~100 m
thick C-layer
-
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use carbon for nano-technologies
6 yr
0
1
4 0
1
S
E
K
A
IT T
A massive steam atmosphere
remains
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water vapor will condense and rain out
M. Beech, Terraforming
Terraforming: Massive freeze-out
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Place a huge sunshade at the L1 point
of venus to block the entire sunlight
Stage
Conditions
Time Taken
1
730 K → 304 K, 95 bar
85 yr
-
atmosphere begins to cool at a rate of 5 K yr-1
2
304 K, 95 bar → 76 bar
22 yr
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after 100 yr: T = 273 K
3
304 K, 76bar → 217 K, 7 bar
94 yr
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after 200 yr: temperature is that low, that CO2 will
freeze-out
4
217 K, 88 bar liquid → solid
17 yr
5
217 K, 7 bar → 192 K, 2.8 bar
9 yr
6
192 K, 800 mbar → 142 K, 3 mbar
4 yr
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solid glacial blanket of CO2 ice will cover the entire
surface
Data from P. Birch, JBIS, 1991, 44, 157-167
Terraforming: Cooling
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Destroy several KBO’s at the L1
point
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debris cloud block out some sunlight
Using pico-sats instead of a debris
cloud
-
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a swarm of ~16 × 1012 satellites with a
diameter of 10 cm and a mass of 1 gram
Louvered sunshade:
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R
E
TWIC
ETE
M
A
I
ED
US
N
E
V
OF
TH
circular parasol with a diameter of 25000
km to completely obscure the sun
M. Beech, Terraforming
Terraforming: Colonisation
Date
Expenditure
Income
Population
2030
≲1G £
-
~1.0E+3
Planing and work for pre-terraformed Venus
2040
~35G £
~2G £
~2.0E+5
Terraforming begins; small space colonies
2045
~115G £
~150G £
~1.6E+6
First free floating colony in venusian atmosphere
2050
~170G £
~510G £
~3.4E+6
Stage 1 cooling complete (2055)
2065
~474G £
~2T £
~1.8E+7
CO2 is raining down (2060); Stage 2 condensation is complete
2080
~1.2T £
~4.8T £
~5.4E+7
2095
~3T £
~9.9T £
~1.3E+8
2110
~7.4T £
~21T £
~3.0E+8
2125
~20T £
~45T £
~6.5E+8
2140
~67T £
~93T £
~1.4E+9
Stage 3 cooling and condensation is complete; first colonies an surface
2155
~90T £
~151T £
~2.7E+9
Stage 4 freezing of oceans is complete (2050); Stage 5 freezing of CO2 gas is complete (2060)
2170
~53T £
~207T £
~4.6E+9
2185
~48T £
~261T £
~7.0E+9
2200
~10T £
~204T £
~1.0E+10
Data from P. Birch, JBIS, 1991, 44, 157-167
Info
Atmosphere and climate are Earth-like
Thank You!
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References:
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http://en.wikipedia.org/wiki/MESSENGER
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http://en.wikipedia.org/wiki/Akatsuki_(spacecraft)
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http://en.wikipedia.org/wiki/Venus_express
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http://en.wikipedia.org/wiki/Atmosphere_of_Venus
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Terraforming: The Creating of Habitable Worlds, M. Beech, Springer
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P. Birch, JBIS, 1991, 44, 157-167, Terraforming Venus Quickly