What Are the Challenges and Proposed Solutions for Terraforming Mars?

[sanman]

Here's another idea -- could we fire an Earth-based laser to divert a sufficiently massive comet to impact Mars?

Comets are of course frozen ice -- often ammonia, which is convenient for our purposes!

If we could find one large enough which was due to pass close enough to Mars, perhaps we could deflect it by heating it, using a long-wave/microwave laser fired from the ground.

A ground-based nuclear reactor or other power source (hydroelectric dam, etc) would avoid the cost of having to launch a reactor into space. Ammonia does have resonance in the Ghz microwave frequency, for heating purposes.

Having your laser operate on a microwave/long-wave frequency would reduce interaction effects with our atmosphere, and would allow you to deliver all your power to the target -- the comet.

Maybe you could locate your laser facility at the North or South Pole, to avoid effects from the Earth's rotation.

You could have your laser zap the target over a prolonged period of time, to gradually deflect it towards Mars.

And maybe we don't even need to exclusively look at comets passing close to Mars. Maybe we consider all known comets and their orbits, in connection with all major planetary orbits -- and then we play Minnesota Fats, exploiting the planetary gravity wells for gravitational slingshot effect.

We could do some combinatorial number crunching to deduce which optimal combination of laser-deflections and slingshots could get an ammonia-comet to hit Mars at the earliest date, within constraints of a feasible energy expenditure on our part.

So what about this idea? Could this work?

 

[Beer w/Straw]

I can't post links but my idea was move Mars closer to where Earth is after diverting a great many asteroids and comets into it. I wonder if the increased mass -to that as Earth's- would make gravity heat up the core for a magnetosphere to that of Earth's


~From old BBC article


Mankind will soon have the ability to move the Earth into a new orbit, say a team of astronomers. The planetary manoeuvre may more than double the time life can survive on our planet, they believe.

Using the well-understood "gravitational sling shot" technique that has been employed to send space probes to the outer planets, the researchers now think a large asteroid could be used to reposition the Earth to maintain a benign global climate.

In the past, some astronomers have suggested that Mars could be terraformed to make it more like the Earth. The Earth-orbital-migration technique, say the researchers, is a far easier way to provide living space for humans in a changing Solar System.

 

[D H]

From old BBC article
Mankind will soon have the ability to move the Earth into a new orbit ...

Here is a link to the article: http://news.bbc.co.uk/2/hi/science/nature/1154784.stm

Some comments:

• "Soon" to an astronomer, especially in the context of the far-from-imminent demise of the Earth via an expanding Sun, is not "soon".
• The lead sentence is journalistic excess. There is nothing in the article that suggests that this will happen (or needs to happen) "soon".
• This is not "soon" (quoting from the article): "Astronomers believe that in a billion years from now our Sun will be over 10% brighter than it is today."
• This is not "soon": "To expand the Earth's orbit around the Sun at a rate that compensates for the increasing brightness of the star would require an asteroid encounter every 6,000 years, or about every 240 generations."
• This is not "soon": "Humans would have many thousands of years to select the appropriate asteroid and develop the necessary technology to deflect the giant rock in the direction of Earth."
• The article is essentially a bunch of scientists writing science fiction.

============================

For instance, Phobos is only 26 km in diameter, an altitude of 10K km, and an orbital speed of just over 2km/s. If we could slow it down, we could drop it on the planet, releasing enough energy to melt the icecaps and maybe even reactivate volcanoes.

This is the problem with science fiction. It is easy to say things like this. It is a tad bit harder to make things like this so. Making Phobos crash into Mars (targeting say 50 km above the surface) would require on the order of http://www.google.com/search?q=1/2*...28+km^3/s^2)*(2/(9250km)-2/(9250km+3450km)))". In comparison, launching the Shuttle into low-Earth orbit consumes about 10¹³ joules.

Maybe we could chop/chip off part of Phobos, and drop that on the icecaps.

Btw, the largest thermonuclear weapon ever detonated was 50 Mt = 2.1×10^17 joules
and that was a half-century ago. I'm not sure what the practical limit is for a thermonuclear explosion, but I bet we could outperform it by thousands of times using today's technology.

Last item first: In terms of the cited Tsar Bomba, the energy needed to drop Phobos onto Mars is 50,000 of those bombs. Do the math! It isn't that hard. A thousand-fold increase in yield? Recreating that bomb would be a challenge, let alone going doing 1000 times better. Using a very high-yield bomb for thrust? Bombs tend to radiate power spherically. How are you going to focus the power from a high-yield explosion to yield thrust? Bringing 50,000 high-yield bombs into space? Please. It will not happen.

============================

My objection to this thread (and the whole colonize Mars meme) is that it throws reality out the window. Attempting to even crack open the reality window doesn't work.

Reality check: The first human visit to Mars won't happen for twenty years minimum, more likely forty years or more away, and possibly never. Human colonization of Mars won't happen for a long, long time. Thinking about colonization now is ludicrous.

• We don't know how to get there and back. We have never had a successful Mars return mission. We have never had an unsuccessful Mars return mission, either. Not knowing at all how to get there and come back is not so good for humans.
• We don't know how to get there, safely. Mars missions have about a 50% success rate. That is good success rate for robots, not so good for humans.
• We don't know what is there that will kill us. Mars dust and extremophiles are unknown hazards that we need to assess.
• We do know many things there that will kill us (temperature, radiation, lack of atmosphere), and we don't know how to overcome those known killers.
• We don't know how to manufacture the requisite items needed for sustaining life in space or in situ.
• We do know that present-day technology would be hard-pressed to meet the challenges of a short-duration human mission to Mars.
• We do know that present-day technology does not meet the challenges of a permanent human presence. NASA has developed extensive lists of things we know we don't know when it comes to Mars exploration. This accounting does not account for the things of which we are totally oblivious.

 

[Beer w/Straw]

Myself I didn't think it would be "soon", neither am I loosing sleep about the sun warming up.

But you didn't address all of my post. Is it feasible by way of a "slingshot" affect with an asteroid? Can someone tell me if mass is added to Mars. Its gravity is increased with its increase in size. That this could speed up the rotational period to that as Earth's which would seem to have an effect on a molten iron core. And have it as well with added friction from gravity make the core active again producing a magnetic field to that as Earth's as well?

Do you think Galileo might have wondered what it would be like to be on another planet even though in his lifetime he knew he would never get there?

 

[DaveC426913]

Is it feasible by way of a "slingshot" affect with an asteroid?

What this is used to do is to move a planet to a new orbit. You could, over many thousands of years, move Mars closer to the Sun to raise its temp. However, at some point you'd be crowdinbg Earth's personal space, casuing orbital perturbations as well as quakes.

Can someone tell me if mass is added to Mars. Its gravity is increased with its increase in size.

Well in theory, but
1] Earth is ten times the mass of Mars.
2] The total mass of all the asteroids in the Solar System is less than 1/10th that of Mars. (http://www.nineplanets.org/asteroids.html" )

That this could speed up the rotational period to that as Earth's

No it wouldn't. In fact, it would slow it down.

which would seem to have an effect on a molten iron core. And have it as well with added friction from gravity make the core active again producing a magnetic field to that as Earth's as well?

Also no, but less so. The Earth started molten and has been keep from solidifying due to gravitational and radioactive effects. In theory, adding mass to a planets might generate some heat from gravitational compression, but you wouldn't be adding any radioactive material. And who knows how much you'd have to increase the planets mass to get it to re-liquify.

 

[Beer w/Straw]

Thanks for the reply.

I was going to post about super duper laser beams to melt Jupiter -a laser to be named after my cat no less but NASA won't return my calls- but I'll save that one my another thread.

 

[sanman]

http://sciencelinks.jp/j-east/article/200623/000020062306A0915942.php

Hmm, that kind of sounds like the type of propulsion we want, to deflect a comet's path.
A beam of heavy ions accelerated to near-light speeds could transfer significant momentum or KE to a comet over time.
We could steer/aim it using magnetic fields, to hit the comet for a prolonged period of time, to shift its path.
We'd just need a big enough ion beam.

Hey, so what are those guys at CERN doing with their LHC, after they finish looking for the Higgs Boson?

But so tell me, in principle, couldn't we theoretically look for some combination of beam-deflections and gravitational slingshots that would reduce the energy cost of creating a significant impact between a comet and Mars, as compared to the energy cost of de-orbiting Phobos, for example?

 

[maze]

Deimos would only require less than 10^21 joules

 

[sanman]

So that's only about 100 Space Shuttle launches, then. That kind of energy could be beamed over to Deimos from the Earth's surface, gradually over a period of time. If timed correctly, then Deimos could be collided with the Southern icecap to vaporize it. Or perhaps an arbitrary collision with Mars could reactivate volcanism, to spew out more gaseous material and give Mars some decent air pressure and temperature.

Then we could send in the photosynthetic bacteria, or thermophilic bacteria, to start reprocessing that CO2 into oxygen.

If we can spend all that money on building LHC, then why can't we spend similar money on de-orbiting Deimos?

 

[D H]

Deimos would only require less than 10^21 joules

Your calculation is off by 50%; Deimos has a mass of 1.48e15 kg. Rounding 9.48 down to 9 is fine, but rounding 1.48 down to 1 is hardly ever fine. But you do not need to kill off all of the velocity. All you need to do is lower the perimars so the orbit is within the atmosphere. Call it http://www.google.com/search?q=1/2*...m^3/s^2)*(2/(23460+km)-2/(23460+km+3450km)))".

So that's only about 100 Space Shuttle launches, then.

Say what? Getting a Shuttle into LEO requires 10¹³ joules. $10^{21}/10^{13} = 10^8$, or 100 million Shuttle launches.

 

[maze]

Ahh, did I drop a constant? In any case...

You could get away with a lot less energy if you simply pushed one of the moons into an elliptical orbit to collide with the other one. And plus, even without a moon-moon collision, there's probably a way to rejigger the 3 body problem to make one of the moons hit Mars without totally stopping one of the masses.

I'm betting you could do it for ~5*10^19 J

 

[D H]

You could get away with a lot less energy if you simply pushed one of the moons into an elliptical orbit to collide with the other one.

Making Phobos hit Deimos would take more energy than making Phobos hit Mars. Making Deimos hit Phobos might send some chunks hit Mars, but unless the bulk of the two bodies would not.

And plus, even without a moon-moon collision, there's probably a way to rejigger the 3 body problem to make one of the moons hit Mars without totally stopping one of the masses.

First, you do not need to completely stop a body orbiting some planet to make it collide with the planet. You simply need to lower the periapsis to within the planet's atmosphere. It costs a lot more energy (in terms of fuel) to launch the Shuttle than it takes to make the Shuttle land. The atmosphere supplies the rest of the energy needed to slow the Shuttle to landing speed.

Second, the gravitational attraction between Phobos and Deimos is dwarfed by their attraction toward Mars. The "3 body problem" will not come to your rescue. And even if it does ...

I'm betting you could do it for ~5*10^19 J

For the sake of argument, I'll grant you this claim. So what? You have reduced the energy to a mere 50 million Shuttle launches.


=================================================

You pro-terraforming guys are, to be blunt, a bit nuts. The kinds of energies you and sanman are talking about harnessing are not only far beyond anything we are can achieve now, they are far beyond anything we can envision achieving far into the future. If I am lumping you two in with the "colonize Mars" crowd, my apologies. Many in that crowd are demanding that NASA not only develop plans for terraforming Mars, they are demanding that NASA divert their very meagre resources to this end starting now. This is, IMHO, simply insane.

 

[maze]

As has been stated previously, Tsar Bomba, detonated in 1961, had a yield of 2*10^17 Joules, and the design was capable of 4*10^17 Joules.

Now 5*10^19 doesn't seem so large... a couple hundred Tsar Bomba's would do it.

 

[B. Elliott]

As has been stated previously, Tsar Bomba, detonated in 1961, had a yield of 2*10^17 Joules, and the design was capable of 4*10^17 Joules.

Now 5*10^19 doesn't seem so large... a couple hundred Tsar Bomba's would do it.

And with the explosive energy of two hundred Tsar Bomba's available, how do you suggest using that energy in such a way that all of it can be directed as push in just one direction?

 

[D H]

Now 5*10^19 doesn't seem so large... a couple hundred Tsar Bomba's would do it.

Get real! To move Deimos,or Phobos, or some other rock, the energy has to be focused and constrained. In case you hadn't noticed, the Tsar Bomba is --get this -- a bomb. A very big bomb that releases an incredible amount of energy in an incredibly short interval of time and over four pi steradians. How are you going to direct the energy in one direction and keep the energy from blowing up the rock you want to move?

Not only is the Tsar Bomba a bomb, it is a nuclear weapon. Nuclear weapons are banned from space. People protested against launching Cassini because it had a puny little RTG. What do you think the world's reaction would be regarding launching "a couple hundred Tsar Bombas" into space?

Where is the moderator for this thread?

 

[B. Elliott]

Not only is the Tsar Bomba a bomb, it is a nuclear weapon. Nuclear weapons are banned from space. People protested against launching Cassini because it had a puny little RTG. What do you think the world's reaction would be regarding launching "a couple hundred Tsar Bombas" into space?

Agreement Governing the Activities of States on the Moon and Other Celestial Bodies

Article 3
3. States Parties shall not place in orbit around or other trajectory to or around the moon objects carrying nuclear weapons or any other kinds of weapons of mass destruction or place or use such weapons on or in the moon.

http://www.unoosa.org/oosa/en/SpaceLaw/gares/html/gares_34_0068.html Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies

Article IV
States Parties to the Treaty undertake not to place in orbit around the Earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner.

http://www.unoosa.org/oosa/en/SpaceLaw/gares/html/gares_21_2222.html

 

[maze]

Get real! To move Deimos,or Phobos, or some other rock, the energy has to be focused and constrained. In case you hadn't noticed, the Tsar Bomba is --get this -- a bomb. A very big bomb that releases an incredible amount of energy in an incredibly short interval of time and over four pi steradians. How are you going to direct the energy in one direction and keep the energy from blowing up the rock you want to move?

One could place the explosives in a parabolic crater, and/or use 400 or 600 tsar bomba's instead of 125 to ensure enough energy is directed in the right direction. Wasting energy blowing the moon apart instead of pushing it is an issue worth consideration, however.

Not only is the Tsar Bomba a bomb, it is a nuclear weapon. Nuclear weapons are banned from space. People protested against launching Cassini because it had a puny little RTG. What do you think the world's reaction would be regarding launching "a couple hundred Tsar Bombas" into space?

Well, that's not really a engineering problem so much as a political one.

 

[D H]

Thank you, B. Elliot! I was afraid I was the only voice of sanity in this thread.

Maze and sanman: What exactly is your intention here? If you want to discuss near-term policy, fine. Stop the science fiction if that is the case. If, on the other hand, you want to discuss science function, that is fine too. Keep it a bit real, and don't even begin to pretend that humanity should begin moving in this direction.

 

[maze]

I don't pretend to know what "humanity" should or should not do. It's just an interesting engineering thought experiment.

 

[D H]

No, its not. Engineering is deeply concerned with feasibility, cost, liabilities, and practicality. This thread has degenerated into the realm of science fiction.

 

[sanman]

Exactly, since this is a discussion board, we should not be afraid to discuss.

Suppose we could use a nuclear explosion to precisely split off a sizeable chunk of Phobos or Deimos, to send that spiraling down to Mars, and hit the icecaps.

Maybe dropping a whole moon is overkill. Maybe we just need a 1000-meter diameter chunk to fall on the icecaps, and also time it for the right part of the year, for best overall weather conditions.

An expanding CO2 gas cloud in the low Martian atmospheric pressure (1% Earth atm) would expand more rapidly to cover a wider area. If we were to create one at the right time of day, right time of year, etc, perhaps we could reduce the size requirements.

 

[D H]

This is a scientific discussion board. There are plenty of other boards out there where you can discuss pseudoscience.

 

[sanman]

Also, what about the idea of dropping some big nukes on Mars?
Perhaps something could be specifically engineered to minimize the production of fallout and residual radioactivity - not that Mars doesn't currently have high levels of radiation from space.
If you could create an atmosphere, you might improve the radiation situation overall.

The largest nuclear weapon ever detonated was a Soviet explosion in 1961, which was 50 Megatons, using a bomb that weighed 27 tons. But nobody has said this was 27 tons of fuel. I'm imagining that a lot of this was from the overall apparatus and casing, which would have been designed back in that very first decade of Soviet nuclear technology.

There were no supercomputers back then, or other modern tools to achieve the design efficiencies possible with today's technology.

I'm wondering if today it wouldn't be possible to build not just a more powerful and lighter weapon, but also to create a shaped explosion with a flatter, more lenticular shape to radiate energy horizontally more than vertically. That would cover more icecap area.
Maybe an appropriately shaped multi-stage bomb design could do that.

(Although blast radius in vertically downward direction could perhaps have the benefit of breaching the Martian crust to liberate geothermal energy. The Martian crust is also peculiarly thin in the northern polar region, at 32 km thickness. Also, creating lower depressions would afford higher atmospheric pressures and temperatures at those depths, which might be more conducive to liquid water and supporting life.)

 

[D H]

Stop with the nukes. It ain't going to happen.

 

[maze]

This is a scientific discussion board. There are plenty of other boards out there where you can discuss pseudoscience.

I think you are confusing pseudoscience with impractical science. Rough estimates have already demonstrated that it is potentially feasible, if impractical, to effect serious change in the orbit of a small moon with energies available to us. If you are not interested in this subject, I recommend you stop reading the thread.

 

[B. Elliott]

I think you are confusing pseudoscience with impractical science.

Due to the fact that nukes in space are outlawed by the order of international space law, it's currently impractical and will remain that way intil those laws are changed.

 

[B. Elliott]

Overly Speculative Posts:
One of the main goals of PF is to help students learn the current status of physics as practiced by the scientific community; accordingly, Physicsforums.com strives to maintain high standards of academic integrity. There are many open questions in physics, and we welcome discussion on those subjects provided the discussion remains intellectually sound. It is against our Posting Guidelines to discuss, in most of the PF forums, new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current professional mainstream scientific discussion. Posts deleted under this rule will be accompanied by a private message from a Staff member, with an invitation to resubmit the post in accordance with our Independent Research Guidelines. Poorly formulated personal theories, unfounded challenges of mainstream science, and overt crackpottery will not be tolerated anywhere on the site. Linking to obviously "crank" or "crackpot" sites is prohibited.

 

[maze]

Those rules apply to crackpot theories of the laws of physics, not strangely novel applications of correct laws of physics.

I find it hard to believe the level of hatred this thread is generating.

 

[D H]

It is not hatred, it is frustration. The thread started on a bad footing and just got worse.

Thread reported.

 

[B. Elliott]

Those rules apply to crackpot theories of the laws of physics, not strangely novel applications of correct laws of physics.

I find it hard to believe the level of hatred this thread is generating.

It's not hatred as I share the same dreams as you do and have had the exact same thoughts as you're having. It's just that you have to know where to draw the line with practicality.

 

[Astronuc]

The proposals for terraforming, particularly with thermonuclear bombs, were presumptive and didn't address some fundamental issues with respect to feasibility, particularly with respect to atmospheric retention. One must consider what is available to terraform Mars and the goal of such a program.


Mars information from http://en.wikipedia.org/wiki/Mars
The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds.

Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. Mars's axial tilt is 25.19°, which is similar to the axial tilt of the Earth. So a Martian winter would be nearly twice as long as one on earth, and perhaps much colder.

Surface temp.
min . mean . max
186 K 227 K 268 K
-87°C -46°C -5°C

So for humans to live in an environment similar to that of Earth, the max temperature of Mars would have to be increased by about 30-35°C, and ideally the minimum would increase by about 50°C, otherwise significant thermal differentials would drive extreme weather (i.e. high wind velocities). Given that Mars is 1.52 AU from the sun, it receives less than half the solar energy flux as the Earth (~43%).


But one has to ask, why Mars doesn't have an atmosphere. Well, it simply doesn't have enough gravity to retain the light gases like N₂, O₂, and water vapor H₂O. So, even if the CO₂ on Mars was released and converted to O₂, and the water was released as vapor, the O₂ and H₂O would simply escape to space, especially if the temperature were to be increased to levels experienced by Earth's atmosphere.

http://zebu.uoregon.edu/~soper/Mars/atmosphere.html

So the gravity would have to be increased on Mars by adding mass,
but then from where would the extra mass come. Phobos? Deimos? Asteroids?

Consider the following:

Mars - mass = 6.4185×10²³ kg / 0.107 Earths
Equatorial surface gravity 3.69 m/s² (0.376 g)

Phobos - mass = 1.07×10¹⁶ kg (1.8 nEarths)
Deimos - mass = 1.48×10¹⁵ kg

The masses of Phobos and Deimos are inconsequential, being less than one ten-millionth of the mass of Mars.


Well - what about the asteroids?


More than half the mass within the main belt is contained in the four largest objects: Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea. All of these have mean diameters of more than 400 km, while Ceres has a diameter of about 950 km.

From - http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)#Physical_characteristics
The combined mass of the current asteroid belt is only a small fraction of the mass of the Earth's Moon - mass 7.3477×10²² kg (0.0123 Earths)

The mass of Ceres has been determined by analysis of the influence it exerts on small asteroids. The mass of Ceres comprises about a third of the estimated total 3.0 ± 0.2 ×10²¹ kg mass of the asteroids in the solar system, together totalling about 4% of the mass of the Moon.

Ceres - mass 9.43 ± 0.07×10²⁰ kg, orbit semi-major axis 414,703,838 km
Kovacevic, A.; Kuzmanoski, M. (2007), "A New Determination of the Mass of (1) Ceres". Earth, Moon, and Planets 100: 117–123.
http://adsabs.harvard.edu/abs/2007EM&P..100..117K

Pitjeva, E.V. (2005), "High-Precision Ephemerides of Planets — EPM and Determination of Some Astronomical Constants," Solar System Research 39 (3): 176.
http://iau-comm4.jpl.nasa.gov/EPM2004.pdf

4 Vesta - mass 2.7×10²⁰ kg, orbit semi-major axis 353,268,000 km

2 Pallas - mass 2.2×10²⁰ kg, orbit semi-major axis 414,784,000 km

10 Hygeia - mass 8.6 ± 0.7 ×10¹⁹ kg, orbit semi-major axis 469,345,000 km

http://en.wikipedia.org/wiki/Image:Moon_and_Asteroids_1_to_10.svg


Collecting all the asteroid mass in solar system, would yield about 4% (0.04) of the lunar mass, which is 11.4% (0.114) mass of Mars. So adding all the asteroid mass to Mars would increase its mass 0.04 * 0.114 = 0.00456, and that would still be insufficient to retain an atmosphere with density and temperature similar to earth. Even adding the moon with the asteroids would only increase the mass of Mars by approximately 12%, and it would still be insufficient.


What about the moons of Jupiter and Saturn? Well, they are a long way off, and one would have to lift the moons out of the gravity wells of Jupiter and Saturn.


Jupiter - orbit semi-major axis 778,547,200 km

Saturn - orbit semi-major axis 1,433,449,370 km