New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: We've recently made changes to our user database and have removed inactive and spam users. If you can not login, please re-register.

#1 2007-07-21 03:18:08

RickSmith
Member
From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Frequently Asked Questions - Mars Terraforming

My intention is to have this thread answer common questions about Mars and Terraforming with indexes to appropriate topics.


Q--- WHAT IS TERRAFORMING?  WHAT IS ECOPOEISIS?

A-- Terraforming is modifying another planet to make it more Earth like.  Some people distinguish between Ecopoeisis (spreading bacterial life to another world) and Terraforming by which they mean to allow humans to walk around on the planet's surface without life support.  Most posts on this forum mean either when they talk about it.  Some scientists have suggested that with a modest effort, Mars could be terraformed which is the main theme of this forum, altho some have posted on terraforming other worlds such as Venus.


Q--- WHAT ARE THE MAIN PROBLEMS FOR LIFE ON MARS?

A--- There are several problems:
--1) The first problem is the air pressure.  It varies from 6 to 14 mBars. (milliBars = 1/1000 of a Bar.  1 Bar is about 99% of an atmosphere.) Earth by contrast has 1.101325 Bars at sea level.  Mars is therefore at a near vacuum and multicellular life will soon die.

Info on Breathable Atmospheres.

--2) The second problem is the cold.  Tho occasionally the temperature gets above freezing on the equator, most of the time Mars is far below freezing.  A typical night temperature is -90C and the temperature at the south pole in southern winter is -127C.  This low temperature is enough to freeze out carbon dioxide ( CO2 ).  So much CO2 freezes out that the planetary air pressure drops significantly each Martian winter.

--3) A third problem is radiation.  Earth's magnetic field directs much of the ionizing radiation from the sun to the polar regions.  Mars has no strong magnetic field so these are spread over the whole planet.  Second the atmosphere is too thin to stop cosmic rays.  Third there is no ozone layer ( O3) so dangerous ultraviolet light sterilizes the surface.

--4) The low gravity complicates keeping a thick atmosphere.

--5) Finally the atmosphere is almost pure CO2.  Animals and higher plants need oxygen ( O2) so anyone breathing Martian air would soon smother.  There are numerous other problems but if you solve these, the rest will take care of themselves.




Q--- HOW WOULD YOU TERRAFORM MARS?

A--- There are 3 main ways suggested in the scientific literature. (I am following the suggestions of Zubrin, McKay and Fogg here.)

--1) First drop comets or icy asteroids (iceteroids) on Mars.  This will thicken the atmosphere which will allow it to retain more heat via the greenhouse effect.  In addition it would be good to add more nitrogen (N2) to the Martian air.

Moving Asteroids Around the Solar System.


--2) Second warm the planet with big mirrors, especially the south pole.

--3)  Third add super greenhouse gases to the atmosphere.  Substances such as the perfluorocarbons such as Tetrafluoromethane (CF4), Hexafluoroethane (C2F6) have been suggested.  In addition Sulfur hexafluoride (SF6) and Nitrous Oxide (N2O) are possibilities.  A recent scientific paper suggests Octafluoropropane (C3F8) since it blocks heat in a wide band.  But putting relatively small amount of these and other gases in the atmosphere, the planet can be warmed 20 to 40 degrees.

Info on PFC's and Are they Toxic?
Info on Greenhouse Gases
How Much PFC's will we need?

Tho not sufficient on its own, darkening the polar regions with dust from an carbonaceous chondrite asteroid (or Phobos or Demos) will increase the effectiveness of light falling on the ice by decreasing its albedo.

Darken Mars With Phobos' Dust

The four methods suggested above could be done with current technology.  There are other more exotic ideas on how to terraform that would require new technology, or moving massive amounts of material around the solar system so are not near term solutions.

One suggestion is 'moholes'.  Giant holes that go down into the mantle of the planet to bring up heat and deep gases.  Moholes are discussed in the thread below (a few posts down.)
Methods of Terraforming

If Mars had more mass things would be nicer.  However, moving enough mass around to make a difference is a far, far future job.
Adding Mass to Mars.

Discussion of Orbital Mechanics Needed to Adjust Planetary Orbits.

If Mars had a giant moon, its climate would be more stable over millions of years.
Large Moons and Angular Momentum

Using self-reproducing nanotechnology is often suggested to give Mars an atmosphere by breaking apart rocks, giving Mars a magnetic field, darkening the planet and many other ideas.  I have made a critique of using 'Magical Nano-tech' to solve our problems for us.
Problems With Magical Nano-technology

Vulcanism is useful for life in many ways.  In the thread below people speculate on ways to get Mars percolating again.
Reheating the Martian Guts


Q--- WHAT IS 'LEVERAGE' IN TERRAFORMING?

A--- Leverage is when relatively small changes to starting conditions cause a large effect.  On Mars people have noticed that if the poles could be warmed by only a few degrees a great deal of CO2 will be given off.  Since carbon dioxide is a greenhouse gas, this will further warm the planet.  More carbon dioxide is trapped by the cold temperatures in the soil and ice, so with sufficient warming the atmosphere could get even thicker and warmer.

Mars has had long periods in the past where it was much warmer.  It seems to have two stable states, a wet and warm state and a cold near vacuum state.  The hope is to be able to make a small change to flip the Martian climate into a life-friendlier area.


Q--- DOES MARS STILL HAVE WATER?

A--- Almost certainly yes.  Mars is a desert not because it has no water, but because the water it has is frozen.  That said, Mars seems to have a lot less water than Earth.  This is because with its lower gravity and no ozone layer water breaks up into hydrogen and oxygen and the hydrogen is then lost to space. 

How Quickly Does Mars Lose Air?


Q--- MARS DOES NOT HAVE A MAGNETIC FIELD.  IS THAT A PROBLEM?

A--- Not a big problem but it is inconvenient in a couple ways.  First the sun's solar wind strips bit of atmosphere away very slowly.  This is thought to have contributed to Mars' low air pressure.  Second Mars thin atmosphere is enough to protect from the sun's radiation except during a large solar flare.  (Astronauts would have to go into a storm cellar during a solar storm.)  If Mars had a magnetic field and the astronauts were not at a magnetic pole then they would be largely protected.

If we thicken Mars' atmosphere (to say 1 Bar) it will last for billions of years.  It will also protect against solar radiation and cosmic rays better than the Earth (with a magnetic field) because Mars' atmosphere has a larger scale height than Earth.

mlomg started a thread that points out that some people think Mars is at a magnetic minimum and a magnetic field will naturally recover over thousands or millions of years.  See:
Mars' Magnetic Field May Recover?

On a somewhat related note, here is a thread talking about radiation protection:
Low Mass Radiation Protection.



Q--- WOULDN'T YOU HAVE TO MAKE SOIL?

A--- Absolutely.  Plants can't live in the sterile (perhaps toxic) soil of Mars.  (I think that the danger of 'super oxides' in Mars' soil is over rated.  Nothing that getting it wet wouldn't fix.  Also Earth plants have been grown in soil made out of simulated Martian regolith with no problems.) The following links talk about soil creation:

Making soil with peat bogs.

Making soil with salt marshes.



Q--- WHAT BOOKS TALK ABOUT TERRAFORMING?

A--- I would suggest first of all "The Case For Mars" by Robert Zubrin.  See also the link below:

Reviews of Books on Terraforming.




Q--- WHERE ARE BASIC FACTS ON MARS?

A--- Try here.

Offline

#2 2007-07-21 04:38:06

RickSmith
Member
From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Frequently Asked Questions - Mars Terraforming

This is the location for Information about terraforming other bodies that are not Mars.

Q--- HOW WOULD YOU TERRAFORM VENUS?

A--- Terraforming Venus is a much harder problem for two reasons.  It has almost no water at all, and its CO2 greenhouse atmosphere is hot enough to melt lead on the surface.  It also has a very long day and no strong magnetic field.  On the bright side its gravity is the same as Earth's.

Many people suggest that we use plants of some sort to convert the CO2 to O2.  Photosynthesis uses this formula:

6 CO2(gas) + 12 H2O(liquid) + photons → C6H12O6(aqueous) + 6 O2(gas) + 6 H2O(liquid)

Or in a simplified form as:

6 CO2(gas) + 6 H2O(liquid) + photons → C6H12O6(aqueous) + 6 O2(gas)

Note that for each molecule of O2 produced, you use up one molecule of water.  So if you could somehow engineer some algae that could live in the cloud tops, (without many major and trace elements needed by the cells for their basic metabolism), you would create a tiny amount of O2, use up all the water and still have about 90 bars of CO2.

Martyn J. Fogg discusses this in his Text book: "Terraforming: Engineering Planetary Environments".  He suggests building a diffraction grating to angle much of the sunlight away from the planet, dropping comets on the now frozen planet to give it some water, and then allow a certain amount of light thru.   The massive amounts of CO2 are also a problem.  It has been suggested to turn much of it into diamond and then bury it.

Terraforming Venus takes a lot more high tech effort to do and maintain than Mars.

Venus and Titan

Discussion on Terraforming Venus



Q--- WHAT ABOUT TERRAFORMING EUROPA, TITAN OR POINTS FURTHER OUT?

A--- Fogg discusses this but the problem is it gets COLD beyond the orbit of Mars.  Also beyond Jupiter's orbit the sunlight in not intense enough for photosynthesis so you need artificial lights for plants (which require a truly remarkable amount of energy).  However, with a sufficiently high technology, we can do magical things.

Terraforming Jupiter's Moons.

Can Small Bodies Be Given An Atmosphere?

And what about Neptune???



Q--- WHAT ABOUT TERRAFORMING THE MOON?

A--- It has been widely suggested that if you could give Luna, our moon, a thick atmosphere it would last for several tens of thousands of years.  Long enough to allow people to keep refilling it with comets grabbed from the Oort cometary belt.

However in this post (which I link to below) Shawn Barrett has shown that this atmosphere would only last 500 years or so.  I think that that pretty much kills the idea of making Luna into a habitable planet unless we postulate some exotic means to keep the atmosphere around it.

Shawn Barrett's Post showing a Lunar Atmosphere Would Likely Only Last from 300 to 1000 Years.

The moon also lacks carbon, nitrogen and hydrogen in large quantities (and many other non-refractory elements) which will greatly increase the cost of terraforming this world.  The month long day also would be very hard for Earth plants to adapt to.  However, the link below talks about the problems and opportunities of improving our nearest neighbor.

Terraforming Luna.



Q--- HOW ABOUT TERRAFORMING OGLE-2005-BLG-390Lb???

A--- If you take me 20,000 light years then I'll give it a try!

Big And Cold Under a Red Sun.


Q--- ANY INFORMATION ON GLIESE 581?

A--- Need More Than Just Water.

Offline

#3 2007-07-21 19:37:32

RickSmith
Member
From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Frequently Asked Questions - Mars Terraforming

MARS DATA:

Orbital Data:
---------------

Semi-major axis.....1.5237 AU.......227,936,637 km
Aphelion.................1.6660 AU......249,228,730 km
Perihelion...............1.3813 AU.......206,644,545 km

Eccentricity.............0.09341233

Orbital speed
- average...............24.077 km/s
- maximum.............26.499 km/s
- minimum..............21.972 km/s

Inclination................1.85061 degrees.
Inclination................5.65 degrees to sun's equator.

Longitude of ascending node......49.578 degrees

Argument of perihelion..............286.462 degrees.

Sidereal period
- Earth days................686.9600
- Julian years..............1.8808
- Martian days.............668.5991 (sols)


Natural temperature of space craft at Mars Orbit: 5° C
Natural temperature of space craft at Earth Orbit: -47° C
(These values can be raised or lowered by the surface texture and color.)

Note: Liquid Nitrogen boils at -196°C (77K) at 1 atm pressure.  Critical temperature is -146.9°C (147K).

The maximum super conduction temperature is at 138 K, is held by a cuprate-perovskite material.  Sadly, even with reflective coatings we can not get super conducting temperatures at Mars orbit.  (We would have to get out to the main asteroid belt before they will work with out refrigeration.)


The eccentricity of Mars' orbit varies.  Around 1.35 million (Earth) years ago, it had an eccentricity of only 0.2 percent (down from about the 9.3% it has today).  This variation of eccentricity is driven by gravitational effects of the other planets, especially Jupiter and Earth.  In about 1000 years Mars will reach its maximum eccentricity and start declining again.
Its main cycle of eccentricity variation is 95,000 years (slightly shorter than Earth's) but there is a long period variation with a period of several million years.

Because its eccentricity is so great, the southern seasons are much more severe than the northern ones.  When people speak of the 'Martian winter' they are discussing winter in the southern hemisphere when Mars is at aphelion (as far from the sun as it gets).


Physical Characteristics:
----------------------------

Equatorial Radius..............3402.5 km   (53.3% of Earth's)
Polar Radius.....................3377.4 km
Oblateness.......................0.00736

Surface area....................1.448x10^8 km^2
Disk visible from Sun........35,835,616 km^2

Volume............................1.6318x10^11 km^3

Mass................................6.4185x10^23 kg
Mean density....................3.934 g/cm^3

Equatorial surface gravity....3.69 m/s^2..........0.376 g

Escape Velocity.................5.027 km/s

Sidereal rotation................1.025957 days.......24.622962 hours

Rotation velocity at equator...858.22 km/hr.....238.394 m/s

Axial tilt............................25.19 degrees

Moment of Inertia:  0.366

Albedo..............................0.15

Insolation at top of atmosphere:
- Semi-major axis...........................560 W/m^2  (43% that of Earth)
- Aphelion...................................... 468 W/m^2
- Perihelion.....................................681 W/m^2

(Since Mars spends more than 1/2 of its time further from the sun than the semi-major axis, Robert Zubrin suggests an average value of 500 W/m^2 which is easy to remember.)

On the surface, the thin dusty atmosphere reduces the above values by about 100 to 200 W/^2. 

Average Temperature: -63° C or 215K
Highest Equatorial Temperature: 20° C or 293K
Coldest (South) Polar Temperature: -132° C or 141 K

The Blackbody temperature for Mars is: -67° C or 211K   
(For Comparison, the Blackbody temperature of: Venus 11° C or 283 K. Earth -23° C or 249K.  Ceres is -136° C or 137K. Callisto is -178° C or 95K.)

Mars has two moons, Phobos and Demos


Atmosphere:
---------------

Surface pressure............................6 to 14 mbar
--> or about 0.000014 to 0.000033 (??) grams / liter

Composition:
- CO2............................................95.72%
- N2..............................................  2.7
- Ar..............................................   1.6
- O2..............................................  0.2
- CO (carbon monoxide).................. 0.07
- H2O............................................  0.03
- NO (nitric oxide)...........................  0.01

2.5 ppm Neon  (ppm = parts per million.)

300 ppb Krypton    (ppb = parts per billion.)
130 ppb Formaldehyde
  80 ppb Xenon
  30 ppb Ozone
  10 ppb Methane

Scale height................................... 11 km

mean molecular weight (g/mole) 43.34

Wind speed (at Viking site) from 0 to 10 m/s
Wind speed (at Viking site) during dust storm 17 to 30 m/s


Argon (Ar) is more enriched in Mars' atmosphere than any other planet. (When CO2 is condensing at the south pole, transitory Ar concentrations of 30% have been observed.)   This is thought to be caused by Mars having thick primordial atmosphere with normal ratios of all volatile elements.  Over time, the other gaseous elements escaped from the planet or were incorporated into the crust.  This suggests that Mars has gradually lost its atmosphere and not had it blown away in a massive impact.

Methane (CH4) has been detected in the Martian atmosphere.  Since this gas is unstable, it must have been produced in the last 100 years.  Possible sources include out gassing from volcanoes or earthquakes, impact of a cometary body, bio-generation by life or finally the reaction of carbon dioxide, water & the mineral olivine (which is common on Mars) in the crust. 

At Mars' temperature and pressure water vapor occasionally reaches 100% humidity.  This is evidence that Mars has ample ice reserves in its crust.

A significant amount of dust particles about 1.5 micrometers across are suspended in the air.  These help transfer solar heat to the air and give the Martian sky a tawny color.  The very fine dust is a nuisance for colonization efforts in that it is abrasive for machinery with moving parts, is unhealthy to breathe and reduces the effectiveness of solar panels.


Moons:
--------
---> Phobos:

Orbital Data:
---------------

Semi-major axis.....9,377.2 km
Apoapsis................9,628.8 km
Periapsis................9,235.6 km

Eccentricity.............0.0151

Orbital speed average.....2.138 km/s

Inclination................1.093 degrees to Mars' equator.
Inclination................26.04 degrees to the ecliptic.

Sidereal period........0.31891023 days (7h, 39.2 min)
- (Phobos synodic period is 7h, 39.43 minutes.)

Phobos is the closest known moon to any planet.  Being in an equatorial orbit it can not be seen above the horizon from latitudes above 70.4 degrees.  It is well within the synchronous orbit for Mars so tidal effects are lowering its orbital radius by 1.8 meters per century.  It is most likely to break up into a ring of rubble when it reaches an orbital diameter of ~7100 km.  These small bodies will continue to decay and will impact along Mars' equator some millions of years later.  Phobos is expected to last another 30 to 80 million years.

Phobos is inside the synchronous orbit so it will rise in the west, move across the sky in 4 h 15 min, and set in the east.  This happens every 11 hours 6 minutes and so it will do this more than twice a Martian day.

Standing on Phobos looking up at Mars you would see Mars covering 1/4 of the sky.  Mars would be 2500 times brighter than the full moon on Earth.



Physical Characteristics:
----------------------------

Dimensions......................26.8 x 21 x 18.4 km.
Mean radius.....................11.1 km.
Oblateness.......................from 0.31 to 0.12

Surface area....................~6,100 km^2
Volume............................~5,500 km^3

Mass................................1.07x10^16 kg
Mean density....................1.9 g/cm^3

Equatorial surface gravity....0.0084 to 0.0019 m/s^2
(This is about 860 to 190 micro-gravities.)

Escape Velocity.................0.011 km/s

Sidereal rotation................Tide locked so equal to orbital period

Rotation velocity at equator...11.0 km/hr (at longest axis' tips)

Axial tilt............................0.00 degrees

Albedo..............................0.07

Temperature......................~233K (-40 C)


Phobos (and Deimos) are very similar to carbonaceous (C-type) asteroids with albedos, densities and a spectral return close to these asteroids.


---> Deimos:

Orbital Data:
---------------

Semi-major axis.....23.460 km
Apoapsis................? km
Periapsis................? km
  (These are very close to the semimajor axis as the orbit is very round.)

Eccentricity.............0.0002

Orbital Period..........1.26244 days

Orbital speed average.....1.35 km/s

Inclination................0.093 degrees to Mars' equator.
Inclination................27.58 degrees to the ecliptic.


Being in an equatorial orbit it can not be seen above the horizon from latitudes above 82.7 degrees. 

Deimos is just outside the synchronous orbit for Mars.  Its sun synodic period is 30.4 hours while Mars' synodic day is 24.7 hours so it moves very slowly from the east to the west in Mars' sky.  In fact, it will take 2.7 days from moon rise to set from an observer on the equator.



Physical Characteristics:
----------------------------

Dimensions......................15.0 x 12 x 10.4 km.
Mean radius.....................6.3 km.
Oblateness.......................?

Surface area....................~? km^2
Volume............................~? km^3

Mass................................2.244x10^15 kg
Mean density....................2.2 g/cm^3

Equatorial surface gravity....0.0039 m/s^2
(This is about 400 micro-gravities.)

Escape Velocity.................0.0069 km/s

Sidereal rotation................Tide locked so equal to orbital period

Rotation velocity at equator...? km/hr (at longest axis' tips)

Axial tilt............................0.00 degrees

Albedo..............................0.07

Temperature......................~233K (-40 C)



References:
"Moons and Planets" by W.K. Hartmann
"Entering Space" by Robert Zubrin
Wikipedia
"Mars: A Warmer Wetter Planet" by J. S. Kargel
"Terraforming" by M. Fogg

Offline

#4 2007-07-22 10:58:57

RickSmith
Member
From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Frequently Asked Questions - Mars Terraforming

This post is a stub for now.  I did some research trying to find a list of all the minerals found so far on Mars and this information is very hard to find.  I'll improve this as I get more time.  So far I've got...

# anorthite (CaAl2 Si2 O8 )

# ilmenite (FeTiO3)

# goethite (iron III hydroxyoxide)

# gypsum (calcium sulfate dihydrate) - depending upon the amount of moisture in the immediate Martian atmosphere, the Martian "gypsum" may be bassanite, a "partially dehydrated gypsum" or even anhydrite (anhydrous calcium sulfate)

# hematite (iron III oxide)

# jarosite (iron III potassium hyroxysulfate)

# kieserite (magnesium sulfate monohydrate)

# maghemite (iron III oxide)

# olivine (jewelry's peridot) (the midmember of the fayalite-forsterite iron magnesium silicate series)

# pyroxenes (mineral group)

# jarosite

# alumina (Al2O3)

# silicon dioxide (SiO2)

Offline

#5 2007-07-22 11:25:06

noosfractal
Member
From: Biosphere 1
Registered: 2005-10-04
Posts: 824
Website

Re: Frequently Asked Questions - Mars Terraforming

a list of all the minerals found so far on Mars

You might be interested in this paper and the web site it references ...

Mars Mineral Spectroscopy Web Site
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1356.pdf


Fan of Red Oasis

Offline

#6 2007-07-22 11:35:26

RobertDyck
Member
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 4,921
Website

Re: Frequently Asked Questions - Mars Terraforming

These are the surface compositions calculated from the Thermal Emission Spectrometer instrument on Mars Global Surveyor.
These tables are the supplimental data from the paper A Global View of Martian Surface Compositions from MGS-TES
Joshua L. Bandfield, Victoria E. Hamilton, Philip R. Christensen
Science, 3 March 2000, volume 287, pages 1626-1630

Supplemental Table 1. Deconvolution results for martian surface spectral types 1 and 2. Totals for each mineral group (e.g. feldspars or sheet silicates) were added and reported to the nearest 5% in the manuscript.
Surface type 1    Model-derived modes (%)
Microcline    5.8
Andesine    22
Bytownite    21.5
Bronzite    5.4
Augite1    12.4
Augite3    11.3
Serpentine    4.8
Gypsum    1.8
Calcite    3.7
Dolomite    0.9
Kaolinite    2.4
Illite    9.9
    RMS error (emissivity) = 0.179

Surface type 2    Model-derived modes (%)
Microcline    5.7
Bytownite    27
Actinolite    6.1
Muscovite    5.7
Bronzite    1.6
Augite1    8.4
Forsterite    2.9
Gypsum    4.5
Dolomite    3.3
Fe-smectite    9.2
Illite    2.2
Obsidian Glass    22.8
    RMS error (emissivity)= 0.089

I don't know what augite1 or augite3 are. Augite is a mess, it has a little of everything and many forms depending on the relative quantity of its ingredients. Its chemical formula is (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6.

Note: plagioclase feldspar is a group, depending on the concentration of sodium vs. calcium. The chemical formula for albite is NaAlSi3O8, anorthite is CaAl2Si2O8.
Albite   
Oligoclase     70-90% albite, 10-30% anorthite
Andesine     50-70% albite, 30-50% anorthite
Labradorite     30-50% albite, 50-70% anorthite
Bytownite     10-30% albite, 70-90% anorthite
Anorthite   

Microcline is also feldspar; similar but it has potassium instead of sodium or calcium. KAlSi3O8

Offline

#7 2007-11-21 04:00:28

RickSmith
Member
From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Frequently Asked Questions - Mars Terraforming

LIKELY GREENHOUSE GASES:

On Mars, we wish the green house gases to cover the range from 4 to 17 and
19 to 25 micrometers as these are wavelengths that carbon dioxide does not
absorb well.  Water is a strong absorber of infrared radiation but it won't exist
in the Martian atmosphere any time soon.  It absorbs IR radiation everywhere
except in the range of 8 to 11 micrometers wavelength so gases that absorb
strongly in this area are also welcome.

Thermal Infrared is considered to be radiation between 3 and 25 micrometers.


The following table gives a variety of green house gases.  The table
tries to show how effective the warming will be, over which wavelengths
and show the duration in the atmosphere.

Several entries have question marks after them.  These are from sources
that I am not as confident of or I expect that the numbers from Earth are
likely to vary significantly on Mars.  If people find better data please private
message me with your reference and I will update this chart.

I have found new data from experiments done using Martian Conditions by
a paper by Margarita M. Marinova, Christopher P. McKay, Hirofumi Hashimoto
so this data is much more accurate than extrapolating from Earth conditions.
This results in different values than I've seen in a number of other sites.

Gas......GWP............Wavelength micro meters..................................~duration in atm.
---------------------------------------------------------------------------------------------------------------------
CO2......x1................4 to 4.5, 17 to 18 on Mars................................infinite
H20......x0 (Mars)......Everywhere except 8 to 11..............................0 (frosts out)

CF4.......x6,500........7.5 to 8.5 & several others weak zones (Mars)...>50,000 years
C2F6.....x9,200........5 to 23 w/ gaps; @6.5, 11 to 17& 19 (Mars).....>10,000
C3F8.....x9,190........3 to 25! (Mars) except 4.6 to 4.8......................>5,000?
C4F10...x7,000........?.......................................................................>2,600?  (conservative estimate).
C6F14...x7,400........?.........................................................................3,200
SF6........x23,900......8 to 11 and 18 to 19.5 (on Mars)........................3,200
N2O.......x310...........5?, 8.3?...............................................................  120
SF5CF3..x18,000.....?..........................................................................4050

CH4.......x23.............3.5?, 8?...............................................................<300? (No O2 to react with)
NH3.......x2?..............?...........................................................................<10?
O3..........x?................8?.........................................................................Constantly regenerated based on O2.

GWP = Global Warming Potential over a 100 year lifetime.  Note that most
of this data is for Earth.  Mars has about 1/2 the UV flux which will extend the
lifetime of these species.  However, the bands of UV that are stopped by the
Earth's ozone layer may cause a faster break up until the O2 concentration
can be raised.  Some think that SF6 is destroyed by electrical effects caused
by the Earths magnetic field and auroras.  If this is the case then its survival
on Mars may be longer than shown above since Mars has no significant
magnetic field.

The GWP of C3F8 is likely 2.5 to 3 times larger on Mars but the article did not
give these numbers so I left it at Earth values which we do have data for.


SF5CF3 = Trifluoromethyl Sulfur Pentafluoride.  This is a new gas I found in
my researches.  Not much data on it but it is included with hopes that we can
find more information later.

N2O = Nitrous Oxide.  The main advantage to N2O is that it does not require
fluorine.  Fluorine is a used in most of the other greenhouse gases since its
covalent bonds are so strong that compounds made of it are very resistant
to chemical reactions and are reasonably immune to UV light.  However
fluorine is a rare element and a major expense will be mining & processing
enough of the suitable ores.  We can make N2O from the air and water so it
may be suitable as an early greenhouse gas before we find large deposits
of fluorine.

The McKay, et all, study singled out C3F8 (Octafluoropropane) as the ideal
gas for terraforming Mars.  On Earth it is less powerful of a greenhouse gas
than Sulfurhexafluoride (SF6) but C3F8 has strong absorption bands that
are covered by water on Earth.  On Mars, these frequencies are critical.  They
found that it was so much better than CF4, that you were better off with a
zero concentration of CF4. 

(The Martians may eventually wish to put in some CF4 in the atmosphere
however, as it has a very long lifetime.  This would act as an insurance
policy in case of a loss of technology.)

Marinova, McKay & Hashimoto recommend the following gas mix:
C2F6 - 15%
C3F8 - 62.5%
SF6   -  22.5%

This mixture was the most effective of the 4 perfluorocarbon gases they
studied.  (They also looked at the absorption spectrum's of some Chlorine
and Bromine gases but did not seriously consider them given that these
species attack ozone.)

Their conclusion was that using the mix above, that 0.2 Pascals would on
its own cause the South Polar cap to sublime all CO2.  (Much less would be
needed if there is a solleta warming it.)  Once the CO2 sublimes, the small
variations wouldn't cause it to freeze out again since the thicker atmosphere
is better at moving heat from the equator to the poles.


Notes:
CF4 boils at -128 C (at 1 atm) 
C2F6 boils at -79C
C3F8 boils at -36.7 C   (These will be much lower at Mars' current pressure.)


REFERENCES:
http://en.wikipedia.org/wiki/Global_warming_potential

Data on Greenhouse Gases

http://www.epa.gov/nonco2/econ-inv/table.html]

http://ucsu.colorado.edu/~browndp/web3d.html

// Spectral absorption website.  Unfortunately, this is specialized in the nano meter wavelengths.
More Info on Spectral Absorptions.

// Place where I found boiling temperatures of gases at 1 atm pressure.
Article Discussing Problems with Greenhouse Gases.

Radiative-convective model of warming Mars with artificial greenhouse gases
by: Margarita M. Marinova, Christopher P. McKay, Hirofumi Hashimoto
Published by the American Geophysical Union. March 2005
(Costs $9 for an abstract.)

Offline

#8 2008-03-01 09:38:44

noosfractal
Member
From: Biosphere 1
Registered: 2005-10-04
Posts: 824
Website

Re: Frequently Asked Questions - Mars Terraforming

The incredibly well researched ...

An upper limit to tolerable CO2 levels by Midoshi
http://newmars.com/forums/viewtopic.php?p=105214#105214

Ultimately, we can state with confidence a conservative lower estimate of 120 mbar for the limit of safe CO2 partial pressure. This raises the possibility that CO2 might actually be used as a significant buffer gas in terraformation.


Fan of Red Oasis

Offline

#9 2008-03-09 02:10:38

RickSmith
Member
From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Frequently Asked Questions - Mars Terraforming

Another fine post by Midoshi which discusses CO2 levels and plants.

Examples of plants at high CO2 levels.


Rick

Offline

#10 2015-05-04 19:47:38

knightdepaix
Member
Registered: 2014-07-07
Posts: 95

Re: Frequently Asked Questions - Mars Terraforming

For choices of greenhouse gases, are oxides of carbon other than CO2 and CO considered ?

Offline

#11 2015-05-04 21:16:58

RobertDyck
Member
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 4,921
Website

Re: Frequently Asked Questions - Mars Terraforming

knightdepaix wrote:

For choices of greenhouse gases, are oxides of carbon other than CO2 and CO considered ?

Oxides of carbon? Carbon trioxide (CO3) as a gas will decay in less than a minute, so isn't useful. Wikipedia: click here
Carbon tetroxide (CO4) will decay even faster. Wikipedia: click here

Offline

#12 2015-05-05 04:27:01

Terraformer
Member
From: Atlantis
Registered: 2007-08-27
Posts: 2,405
Website

Re: Frequently Asked Questions - Mars Terraforming

The trouble is, oxides other than CO2 (and CO, which is toxic) tend to be solid at the temperatures we want, from what I've read. Tricarbon trioxide (C3O3) for example.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

Offline

#13 2015-05-05 08:59:10

RobertDyck
Member
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 4,921
Website

Re: Frequently Asked Questions - Mars Terraforming

Hmm. Interesting. Carbon suboxide

Wikipedia wrote:

Carbon suboxide, or tricarbon dioxide, is an oxide of carbon with chemical formula C3O2 or O=C=C=C=O. Its four cumulative double bonds make it a cumulene. It is one of the stable members of the series of linear oxocarbons O=Cn=O, which also includes carbon dioxide (CO2) and pentacarbon dioxide (C5O2).
...
It is commonly described as an oily liquid or gas at room temperature with an extremely noxious odor.
...
In 1969, it was hypothesized that the color of Martian surface was caused by this compound; this was disproved by the Viking Mars probes.
...
Uses
Carbon suboxide is used in the preparation of malonates; and as an auxiliary to improve the dye affinity of furs.
...
some authors think also that those macrocyclic compounds of carbon suboxide can possibly diminish free radical formation and oxidative stress and play a role in endogenous anticancer protective mechanisms, for example in the retina.

Boiling point 6.8°C
Sounds relatively stable, although stinky. Only gas once Mars is warm, so doubt it's useful.

Offline

#14 2015-08-07 15:44:50

knightdepaix
Member
Registered: 2014-07-07
Posts: 95

Re: Frequently Asked Questions - Mars Terraforming

RickSmith wrote:

LIKELY GREENHOUSE GASES:
On Mars, we wish the green house gases to cover the range from 4 to 17 and 19 to 25 micrometers as these are wavelengths that carbon dioxide does not absorb well.  Water is a strong absorber of infrared radiation but it won't exist in the Martian atmosphere any time soon.  It absorbs IR radiation everywhere except in the range of 8 to 11 micrometers wavelength so gases that absorb strongly in this area are also welcome. Thermal Infrared is considered to be radiation between 3 and 25 micrometers.

https://en.wikipedia.org/wiki/Infrared_ … tion_table

If sorting under wavenumbers, 3,4 to 25 micrometers translate to 3333, 2500 to 400 cm-1.

For SF6, have a look of the abstract of this journal article.
http://www.sciencedirect.com/science/ar … 5288903293
Chapados, C., & Birnbaum, G. (1988). Infrared absorption of SF6 from 32 to 3000 cm−1 in the gaseous and liquid states. Journal of Molecular Spectroscopy, 323-351.

Wavenumbers 32 to 3000 cm-1 translate to 312.5 to 3.333 micrometers; shall these numbers feed the need of greenhouse gases by SF6 ?

Offline

#15 2016-01-31 14:43:58

Cy M
Member
From: Lufkin Texas USA
Registered: 2016-01-22
Posts: 4

Re: Frequently Asked Questions - Mars Terraforming

Ecopoeisis (spreading bacterial life to another world)  Has already happened by the simple fact that we have introduced it both willingly and unwillingly with the rovers and other craft we sent.  Anything built on Earth can not be Decom-ed enough to remove virus  and other bacterial life, some of these can even survive unprotected in space , in hot smokers at the bottom of the sea and in the caves as deep as we can investigate.  Also both Mars and Earth have shared meteors with each other since they existed so this is not new to either world.  The big questions on Mars is 1 Is there any still alive? 2 What other kinds are there? 3 What kinds do we want to willingly introduce? 4 Can we better Decom both ways?


On a quest.

Offline

#16 2017-05-20 16:22:30

knightdepaix
Member
Registered: 2014-07-07
Posts: 95

Re: Frequently Asked Questions - Mars Terraforming

RickSmith wrote:

MARS DATA:

Atmosphere:
---------------

Surface pressure............................6 to 14 mbar
--> or about 0.000014 to 0.000033 (??) grams / liter

Composition:
- CO2............................................95.72%
- N2..............................................  2.7
- Ar..............................................   1.6
- O2..............................................  0.2
- CO (carbon monoxide).................. 0.07
- H2O............................................  0.03
- NO (nitric oxide)...........................  0.01

2.5 ppm Neon  (ppm = parts per million.)

300 ppb Krypton    (ppb = parts per billion.)
130 ppb Formaldehyde
  80 ppb Xenon
  30 ppb Ozone
  10 ppb Methane

Scale height................................... 11 km

mean molecular weight (g/mole) 43.34

Wind speed (at Viking site) from 0 to 10 m/s
Wind speed (at Viking site) during dust storm 17 to 30 m/s

Argon (Ar) is more enriched in Mars' atmosphere than any other planet. (When CO2 is condensing at the south pole, transitory Ar concentrations of 30% have been observed.)   This is thought to be caused by Mars having thick primordial atmosphere with normal ratios of all volatile elements.  Over time, the other gaseous elements escaped from the planet or were incorporated into the crust.  This suggests that Mars has gradually lost its atmosphere and not had it blown away in a massive impact.

Methane (CH4) has been detected in the Martian atmosphere.  Since this gas is unstable, it must have been produced in the last 100 years.  Possible sources include out gassing from volcanoes or earthquakes, impact of a cometary body, bio-generation by life or finally the reaction of carbon dioxide, water & the mineral olivine (which is common on Mars) in the crust. 

At Mars' temperature and pressure water vapor occasionally reaches 100% humidity.  This is evidence that Mars has ample ice reserves in its crust.

A significant amount of dust particles about 1.5 micrometers across are suspended in the air.  These help transfer solar heat to the air and give the Martian sky a tawny color.  The very fine dust is a nuisance for colonization efforts in that it is abrasive for machinery with moving parts, is unhealthy to breathe and reduces the effectiveness of solar panels.

Two questions:
1) Is the Martian atmosphere saturated given the gravity? That means, given the same gravity, can the atmosphere take on more gases without losing them to space?
2) Can the advance of nanotechnology provide some kind of carbon nanomaterial -- or other chemical elements for what it worth -- filters for machinery including vehicles from personal uses to mass transportation? Say once a carbon nanomesh is clotted with those dust, it is exchanged for a clean filter at gas station and thus collected en masse. At a factory, these pieces of nanomeshes are processed as minerals or ores. If carbon based nanomesh can be manufactured, the carbon dioxide in Martian atmosphere will have another use. Analogously, cloud-top Venusian settlement can use nanomesh filters on sulfur oxides.

Last edited by knightdepaix (2017-05-20 16:23:17)

Offline

#17 2017-05-21 06:03:18

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,340

Re: Frequently Asked Questions - Mars Terraforming

1.  My recollection is that a denser atmosphere will be eroded through natural loss to outer space in the absence of a magnetosphere. However, that process will take at a minimum tens of thousands of years before the loss becomes significant. By which time we will no doubt have figured out how to create an artificial magnetic field to retain the atmosphere.

2. I would think that if you can release melt water ice and create a water cycle that results in rain, much of the dust will be washed away down crevices, into river beds and lake beds and so on. That's just a guess on my part, but the air always feels free of dust after heavy rainfall on Earth. In any case having to wear a dust mask would not prevent colonisation.  People in places like the Sahara effectively have to mask their mouths when they step out on a breezy day.


knightdepaix wrote:

Two questions:
1) Is the Martian atmosphere saturated given the gravity? That means, given the same gravity, can the atmosphere take on more gases without losing them to space?
2) Can the advance of nanotechnology provide some kind of carbon nanomaterial -- or other chemical elements for what it worth -- filters for machinery including vehicles from personal uses to mass transportation? Say once a carbon nanomesh is clotted with those dust, it is exchanged for a clean filter at gas station and thus collected en masse. At a factory, these pieces of nanomeshes are processed as minerals or ores. If carbon based nanomesh can be manufactured, the carbon dioxide in Martian atmosphere will have another use. Analogously, cloud-top Venusian settlement can use nanomesh filters on sulfur oxides.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

Offline

#18 2017-05-24 06:52:44

elderflower
Member
Registered: 2016-06-19
Posts: 434

Re: Frequently Asked Questions - Mars Terraforming

I have recently seen reports that very low frequency, very long wavelength transmissions by humans are affecting the radiation environment of earth and to some extent protecting the atmosphere, possibly due to interaction with the magnetic field.
I wonder if this could affect the rate of loss of Mars atmosphere.

Offline

#19 2017-05-28 16:06:47

knightdepaix
Member
Registered: 2014-07-07
Posts: 95

Re: Frequently Asked Questions - Mars Terraforming

louis wrote:

1.  My recollection is that a denser atmosphere will be eroded through natural loss to outer space in the absence of a magnetosphere. However, that process will take at a minimum tens of thousands of years before the loss becomes significant. By which time we will no doubt have figured out how to create an artificial magnetic field to retain the atmosphere.

The Martian atmosphere has been being eroded. If more gases are exhausted to that atmosphere, is the erosion going to accelerating?

Offline

#20 2017-05-29 02:53:34

elderflower
Member
Registered: 2016-06-19
Posts: 434

Re: Frequently Asked Questions - Mars Terraforming

For warming the atmosphere I expect we will use fairly heavy molecules like SF6, and fluorocarbons / chlorofluorocarbons. These won't be eroded at a significant rate, but the rate of erosion of lighter species, particularly water vapour would increase a bit.

Offline

#21 2017-05-29 03:17:09

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,340

Re: Frequently Asked Questions - Mars Terraforming

Well there will be more to be eroded, so yes in absolute terms, I would think. But as long as the gasification rate exceeds the loss rate, your atmosphere will grow. The loss process is slow. You will have thousands of years to think about how to either replenish your atmosphere (e.g. via comet impact) or to construct an artificial magnetosphere (or equivalent).

knightdepaix wrote:
louis wrote:

1.  My recollection is that a denser atmosphere will be eroded through natural loss to outer space in the absence of a magnetosphere. However, that process will take at a minimum tens of thousands of years before the loss becomes significant. By which time we will no doubt have figured out how to create an artificial magnetic field to retain the atmosphere.

The Martian atmosphere has been being eroded. If more gases are exhausted to that atmosphere, is the erosion going to accelerating?

Last edited by louis (2017-05-29 03:17:42)


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

Offline

Board footer

Powered by FluxBB