Iceteroids: What happens when they get to Mars?

nickname · 2007-06-30 05:47:24

Rick,

I think your second question is a better one

If we drop a big snowball on Mars the result will probably be a short term melt followed by a global snow and freeze.

In my opinion we would make Mars a much more difficult place to teraform with reflective snow all over the place that takes a long time to return to the poles if ever.

Maybe we should just use whatever asteroid we find with interesting ingredients as a factory to create super greenhouse gas.

On the years of trip getting it back to Mars we can convert most of the asteroid into super greenhouse gas, the remaining parts of the asteroid used as fuel or just mass ejection objects to slow the speed.
With a little planning we could settle into a gentle orbit of Mars and just release the gas.

We must use some pretty serious planning with greenhouse gas.
We want to have enough of it to get us past the snowball Mars scenario, but not so much that its uncomfortably warm.
If we don't calculate it correctly we could easily see Mars covered in snow and decrease the temperature even with greenhouse gas locking in heat.
Escaping from snowball Mars would require so much greenhouse gas that the escape point needed to melt makes it permanently uncomfortably warm when it melts.

The same mechanism is believed to have happened on Earth a few times with 50c global results after the melt with co2 accumulation from volcanic activity.
Earth has oceans and life to use up the excess co2, Mars has nothing to use up excess super greenhouse gasses.

RickSmith · 2007-06-30 16:39:02

Hi Nickname, thanks for replying.

Rick,
If we drop a big snowball on Mars the result will probably be a short term melt followed by a global snow and freeze.
In my opinion we would make Mars a much more difficult place to teraform with reflective snow all over the place that takes a long time to return to the poles if ever.

I don't see that. Frost at the low latitudes sublimes and moves to those latitudes higher than 40 degrees or works its way deeper into the soil where it is more stable.

The rate is up for debate (also depending on how big an iceball you drop) but current Mars conditions don't have any problem with moving H2O to the poles.

Finally, if we use a carbonaceous chondrites they have plenty of water but are darker than Mars is.

Maybe we should just use whatever asteroid we find with interesting ingredients as a factory to create super greenhouse gas.
On the years of trip getting it back to Mars we can convert most of the asteroid into super greenhouse gas, ....

In a previous post I pointed out that the major expense with the super greenhouse gasses is finding the fluorine. There is no reason to expect that any asteriod or comet would have a significant amount of F. (In fact, I have not heard of any fluorine being detected on an asteriod or comet. Anyone heard otherwise?)

You could make greenhouse gasses like CH4 or NH3 out of comet stuff, but they are only stable for a handful of years under current Martian conditions.

Fluorine minerals are likely to be concentrated by volcanic activity (at the top of magma melts) and to a lesser extent by fluorine salts. Both of these methods of concentrating the element will work on Mars, but probably won't have worked on any asteriod or comet. So I think it would be easier to build the perfluoricarbons on Mars rather than on a comet.

We must use some pretty serious planning with greenhouse gas.
We want to have enough of it to get us past the snowball Mars scenario, but not so much that its uncomfortably warm.
If we don't calculate it correctly we could easily see Mars covered in snow and decrease the temperature even with greenhouse gas locking in heat.
Escaping from snowball Mars would require so much greenhouse gas that the escape point needed to melt makes it permanently uncomfortably warm when it melts.

I've read a lot on terraforming Mars and I think that a big problem is than any time you get a decent amount of water on the equator, is that it will move to the poles and be locked up there.

For this reason, I've been leaning towards Zubrin's suggestion of big solletta's over both poles. That adds heat where we need it. We want the huge amounts of water in the polar regions to join into the hydrosphere.

As Mars gets hotter, more heat will escape, greenhouse gasses or no. (The rate that a blackbody radiates goes up rapidly as you warm it. Also the wavelengths get shorter so more heat will leak out above the wavelenths that the super greenhouse gasses are tuned for.)

I don't think that with 45% of Earth's insolation, we have too worry about Mars getting too hot any time soon.

The same mechanism is believed to have happened on Earth a few times with 50c global results after the melt with co2 accumulation from volcanic activity.
Earth has oceans and life to use up the excess co2, Mars has nothing to use up excess super greenhouse gasses.

A number I often see quoted is that a CO2 molicule stays, on average, for 200 years before it is absorbed by the biosphere. However, most of what the biosphere absorbs it released back into the atomosphere a few years later when the plant dies and rots.

(Historically 100 times more carbon was in the atmosphere than in the biosphere. It is now up to 200 times.)

The iceball Earth theory (which I think likely by the way) points to evidence that Earth froze solid and then seemed to suddenly melt with the temperature rocketing up to 50 C because of the huge amount of CO2 that had built up in the air. But the CO2 was not drawn down by life. (The continents were basically sterile.) The CO2 was drawn down because there was a lot of unweathered rock exposed by glaciers. The hot rainfall made powerful carbonic acid which disolved rocks.

If we keep these threads on topic, it is easier to find information. This thread is intended to be a place where we talk about the details of moving rocks, not what happens when they get here. Perhaps a moderator can move Nickname's post and my reply into its own thread?

Warm regards, Rick

nickname · 2007-07-02 06:02:14

RickSmith,

Mars at the atmospheric pressure its at now is quite good at moving h20 to the poles as frost.

Frost and snow are two very different things though.
The current Mars creates frost.

At 1/4 or 1/2 bar the mechanics of moving water on Mars will be much different, Mars should accumulate snow.

If we try to slowly heat Mars the outcome is sure to be a snowball Mars.

I agree on the finding a useful asteroid/comet/kb.
Looking for bodies with lots of fluorine will be a giant hurdle in itself.
We have lots of other choices of things we can use to make greenhouse gas.
As you point out we need stable long term greenhouse gases for it to work.
Those gasses would be best if they don't destroy a growing ozone layer also.

Mars itself might offer a solution to this problem, a few years of mining for the needed elements, then added to whatever goodies we bring on the incoming body.
We can surely make lots of whatever we need then.

I agree on the snowball earth, it took quite a while for earth to escape it.
The oceans on Earth are pretty good at taking back up the overdose of c02 in the aftermath.

We would defiantly want to avoid the same problem on Mars, most of the super greenhouse gasses we need to warm Mars don't really break down naturally in the environment.
Having to pump in 2 or 3 times the greenhouse gas Mars needs to stay warm to escape a snow ball scenario would be very wasteful.

Whatever we do it will have to be quick and just the right amount of gas.
A little bit to much wouldn't be a bad thing .

The mirrors at the poles i think is a good idea, but would it simply re freeze with little effect on the atmosphere.

Maybe a better use of the poles is to break the h20 into its elements, then use the hydrogen to create super greenhouse gasses.
Sure they will be short term gasses but in unlimited supply.
We could probably do that with small nuclear power stations and factories on the poles.
Mining for long term gas elements at this point would go a long way to a permanent teraform.

Two overlooked bodies are phobos and deimos, they probably both have useful items for a teraform.

m1omg · 2007-07-03 12:07:24

Rather than crash comets into Mars, outgass they into atmosphere.

noosfractal · 2007-07-03 16:58:14

Rather than crash comets into Mars, outgass they into atmosphere.

The nice thing about crashing them is that you get all that heat as well - but of course it isn't really an option if there are already settlers there at the time. Also, not crashing them is a challenge - just shattering them doesn't help, you have to slow them down into Martian orbit.

nickname · 2007-07-03 17:59:14

noosfractal,

I've always wondered about the mechanics of crashing ice asteroids into Phobos or Deimos.

That might be a way without slow down fuel trying to deliver them to a Mars orbit.
We also avoid those big Mars surface kabooms that way.

Also a good way to get those two big ugly rocks out of the Martian view of Earth

Seriously though Phobos is suppose to be covered many meters deep in black carbon soot.
If we can get water or oxygen to Phobos we can make lots of c02 for the Martian atmosphere.
Delivery of the produced co2 involves escape velocities of a few Meters per Second, so a gentle push will deliver it to Mars with no delivery vessel.

noosfractal · 2007-07-03 19:44:07

I've always wondered about the mechanics of crashing ice asteroids into Phobos or Deimos.
That might be a way without slow down fuel trying to deliver them to a Mars orbit.

I quite like this idea. It'd be hard - the incoming iceteroid would be moving very fast - you'd have to adjust it's velocity so that it would arrive at the right phase of the moon's orbit and, of course, the target is a lot smaller - but I think it is possible if you design for it.

We also avoid those big Mars surface kabooms that way.

You'd still get quite a large kaboom at the moon, preferably Phobos, so you'd get some moon dust coming down to Mars as well - but you wouldn't even notice if it came down during a dust storm - and, like you say it's all nice carbon/organic matter.

Also a good way to get those two big ugly rocks out of the Martian view of Earth

A 10 billion ton iceteroid (2.3 km diameter) is about 1/1000th the mass of Phobos - still it'd have quite a bit of momentum and would modify Phobos' orbit, particularly if you hit it repeatedly. Perhaps we could kill two birds with one stone here (as it were) and modify Phobos' orbit so that it isn't in the way of a space elevator.

Seriously though Phobos is suppose to be covered many meters deep in black carbon soot.
If we can get water or oxygen to Phobos we can make lots of c02 for the Martian atmosphere.
Delivery of the produced co2 involves escape velocities of a few Meters per Second, so a gentle push will deliver it to Mars with no delivery vessel.

Not a bad thought, although Phobos with lots of water isn't a bad asteroid mining base by itself (assuming humans can live happily in low g).

nickname · 2007-07-04 07:38:01

noosfractal,

This is a bit off track of the original theme but...

What if we just brought up water or Oxygen from Mars to Phobos, combine it with carbon to produce co2, then simply use the pressure created from storage to deliver it back to Mars.

Solar power for the chemical processes on Phobos.
Solar power for the separation process on the pole of Mars.

Probably best to bring up liquid oxygen from Mars, no need to waste the hydrogen from the process either as a combination of the two gets the vessel/craft to phobos.

I wonder how much c02 we get from a process like that?
Enough to make a decent bar pressure on Mars or maybe enough to start a melt on Mars ?.

I believe we get around 2 inches of black carbon soot it we spread it over all of mars, so its a decent quantity of carbon on Phobos.

Maybe a totally new teraform approach to Mars here?

We can still pummel phobos later with iceteroids

StarDreamer · 2007-07-04 09:10:06

If you melded a few iceteroids into Phobos and/or Deimos, what effect would this additional mass have on the moons? Would it decay their orbits or raise their orbits? It might depend on the ballistics of the "meld".

I wonder if you could migrate the orbits towards each other, by adding inertia to the one and subtracting it from the other, until the two moons collided in orbit.....

nickname · 2007-07-04 14:50:20

StarDreamer,

All depends on how you hit them and the impactor size i think.

noosfractal,

A little more thought on the phobos Carbon to c02 Mars atmosphere.

One big ship or just a few from mars to collect all the carbon soot, then back to the pole for processing.
Cheaper on fuel this way.

We can still use the oxygen and hydrogen separated at the pole for the transport, but much less trips bringing back the carbon to Mars than bringing up liquid oxygen to phobos.
1/2 the trips in fact

The ideal solution is to not launch anything from Mars to collect carbon from phobos, create the carbon collection and Mars landing vehicle on phobos or on the space station in earth orbit or on our moon.
Any of the three make the process a much more efficient one.

Hacking at the math of carbon soot from phobos being able to cover all of Mars 2 inch thick.
I get about 250mb of co2 for Mars atmosphere with this process of carbon conversion to co2.
More than enough to melt Mars and keep it warm.

Difficult math though to convert raw C from Phobos and 02 into quantity of c02 atmosphere.
We also get quite a bit of free hydrogen in this process added to Mars atmosphere or stored for something else.

noosfractal · 2007-07-04 18:02:52

If you melded a few iceteroids into Phobos and/or Deimos, what effect would this additional mass have on the moons? Would it decay their orbits or raise their orbits? It might depend on the ballistics of the "meld".

Because the mass of the moon would still be small compared to Mars, I think it more depends on how you changed the moon's velocity. The most likely outcome is to make the orbit slightly elliptical.

I wonder if you could migrate the orbits towards each other, by adding inertia to the one and subtracting it from the other, until the two moons collided in orbit.....

This might be too difficult, even in principle, but I think there is enough energy if you can organize at least hundreds, probably thousands of impacts.

noosfractal · 2007-07-05 02:45:09

One big ship or just a few from mars to collect all the carbon soot, then back to the pole for processing.
Cheaper on fuel this way.

Or ... build a linear accelerator on Phobos, compact the carbon into bullet shapes and then shoot them at the ice deposits.

Carbon + ice + heat from impact -> CO2 + methane + water vapor

I thought you might be able to burn Phobos carbon like coal for energy, but it would take more energy to split out the oxygen from the water than you'd get from burning the carbon. You could use it to lower the energy cost of CO2 production though.

What an interesting idea, nickname. We need a better characterization of the crust of Phobos to plan in more detail.

nickname · 2007-07-05 06:36:45

noosfractal,

That is a brilliant way to get the carbon to the pole of Mars and do away with the co2 creation machines, landers, launch vehicles, solar power cells etc on the pole altogether.

The escape speed of the bullets would be tiny from Phobos so the linear accelerator wont need to be very powerful.
Might be a bit tricky to get the bullets to the pole, but with such low Phobos escape speed it shouldn't be to hard to guide them.

I agree if we had real good data about Phobos we could make better predictions about what we get from stripping the carbon and sending it to the pole.

The methane from the small impactors on the pole might be just as important as the co2 production.
With your bullet idea we make this a very simple and safe teraform, even with colonists it's still safe for them.
I bet with the quantity of c02 and methane production we could safely get past any snowball Mars scenario before it started.

This is such a simple idea i cant believe someone hadn't thought of it.
Did some surfing last night for something similar but found nothing.

The collection of the carbon soot on Phobos shouldn't be to difficult.
I can't see anything real high tech here we need for any of the processes?
I don't think we are looking at a long term process to do this either, maybe 10 - 20 years with a few collectors and accelerators on Phobos to strip and send it all.
Not much worry about the heat from the small impact bullets on the poles either, as long as we don't melt the pole we are trying to bombard before we run out of bullets.

m1omg · 2007-07-05 14:44:28

Rather than crash comets into Mars, outgass they into atmosphere.
The nice thing about crashing them is that you get all that heat as well - but of course it isn't really an option if there are already settlers there at the time. Also, not crashing them is a challenge - just shattering them doesn't help, you have to slow them down into Martian orbit.

http://en.wikipedia.org/wiki/Terraformi … atmosphere

"Impacting a comet onto the surface of the planet might cause destruction to the point of being counter-productive. Aerobraking, if an option, would allow a comet's frozen mass to outgas and become part of the atmosphere through which it would travel."

AFAIK the comet contains a lot of water and because H2O is a greenhouse gas, the planet will heat up.

RickSmith · 2007-07-05 15:09:11

RickSmith,
At 1/4 or 1/2 bar the mechanics of moving water on Mars will be much different, Mars should accumulate snow.
If we try to slowly heat Mars the outcome is sure to be a snowball Mars.
We would defiantly want to avoid the same problem on Mars, most of the super greenhouse gases we need to warm Mars don't really break down naturally in the environment.
The mirrors at the poles i think is a good idea, but would it simply re freeze with little effect on the atmosphere.
Maybe a better use of the poles is to break the h20 into its elements, then use the hydrogen to create super greenhouse gases.

Hi Nickname, everyone.
If somehow Mars gets too warm (say there is a lot more CO2 than we expect) then when we start plants creating oxygen from CO2, the temperature will drop again. Also black body radiation goes up a lot as the body gets warmer. If Mars gets hot, it will radiate the heat away faster on a wider variety of wavelengths.

Having mirrors directing heat to the poles is a good thing. Yes the snow will land at the poles. But it won't get as cold and more of it will melt come summer. I think we will want to have sollettas warming the poles to:
- melt ice and sublime dry ice.
- drive CO2 out of the soil.
- make glaciers move faster / melt (which will free CO2 clathrates).

As for using making CH4 or NH3 I have my doubts. With the perfluorocarbons, building them up with a slow trickle works because they stay around a long time. With methane / ammonia they are destroyed so quickly (especially with out an ozone layer) I wonder if it would be worth the expense.

Warm regards, Rick.

noosfractal · 2007-07-05 19:53:35

"Impacting a comet onto the surface of the planet might cause destruction to the point of being counter-productive.

Yes, it might, however, presumably we can control the impact energy (i.e., slow the thing down if necessary).

Aerobraking, if an option, would allow a comet's frozen mass to outgas and become part of the atmosphere through which it would travel."

Yes, if an option, however it is very unlikely that you'd be able to ablate a 10 billion ton comet in a single pass, that is, the comet would have to be put in a highly elliptical orbit, with one end of the orbit passing through the atmosphere - but any orbit, highly elliptical or not, may be difficult because you have to slow this huge mass from ~30-40 km/sec to < 5 km/sec. We may not have the technology to achieve this for a long time - we certainly don't today.

AFAIK the comet contains a lot of water and because H2O is a greenhouse gas, the planet will heat up.

H2O is an excellent greenhouse gas, but until temperatures average above zero degrees Celsius, it will (unfortunately) quickly freeze out to the poles. That's why gases like CO2, ammonia & PFCs are so important initially. Once we're in the goldilocks zone, the water will keep the planet there, but we have to get there first.

nickname · 2007-07-06 14:01:50

RickSmith,

I agree the production of greenhouse gas from water/ice on Mars is pretty simple but not a long term life in the atmosphere.

I would think that Mars has pretty similar deposits as Earth does.
We should be able to find a fluorine deposit or fluorine rich rock on or in Mars somewhere.

With fluorine, creating those super greenhouse gasses that last for the long term would be pretty simple, and realistic to warm up Mars for the long haul.

I doubt if Mars will get to warm from greenhouse gasses also.
The only scenario we get into trouble is if Mars gets just warm enough to melt and produce snow all over the place.

Then we loose the ground warmth and have to replace the lost amounts with more greenhouse gas, more than Mars would really need.
As we warm enough with more gas to loose the snow, we now have the additional ground heat and additional greehouse gas heat that we needed to melt snowball snow.

We will probably encounter this at some temperature and atmospheric condition along the way as we are warming and thickening the atmosphere.

If we calculate the point this is likely to happen and just produce gas much faster as we get close, we should be able to avoid a snow ball scenario.

Like you say if we do make it a bit to warm then plants can take up the slack.
I would guess if we make it a bit to warm the rain will scrub lots of co2 anyway.

m1omg · 2007-07-06 14:58:52

I calculated using this; http://www.users.globalnet.co.uk/~mfogg … raSim.html ;

That for warming Mars to avg. temperature of 2 deg. Celsius and creating a 346.5 milibar atmosphere from sublimated CO2 from regolith and cap CO2 inventory you will need 6 microbars partial pressure of PCFs (the same greenhouse effect as CFCs fortunatelly PFCs are not destroying ozone layer).
Ammonia will warm the planet, but will be destroyed when there will be ocygen in the atmosphere and we want breathable air!

That pressure and temperature is enough to support liquid water.

Adding more than 6 microbars will unfortuanatelly not help because from 6 microbars to 7 microbars it would increase average temperature only by 0.1 degress Celsius per 1 microbar and when you will add more than 7 microbars the temperature increase starts becoming more neglible and even if you will add 1000 microbars of it the temperature will be only 0.8 deg. Celsius higher than with 6 microbars (!).
So the 6 microbars of PFC is a reasonable maximum.

StarDreamer · 2007-07-07 02:03:35

re: shooting carbon at the poles ....

Carbon black on ice creates microclimate for melting the ice. The carbon sinks into the glacier as it melts, creating pits. I think Martian glaciers are heavily pitted already from local dust settling on them. As soon as the carbon sinks out of "line of sight" to the Sun, melting slows and stops. So shooting carbon bullets at the poles cannot work except for the little boost at impact. What you end up doing is interring all your precious carbon into the ice, never to be seen again.

noosfractal · 2007-07-07 04:00:40

re: shooting carbon at the poles ....
Carbon black on ice creates microclimate for melting the ice. The carbon sinks into the glacier as it melts, creating pits. I think Martian glaciers are heavily pitted already from local dust settling on them. As soon as the carbon sinks out of "line of sight" to the Sun, melting slows and stops. So shooting carbon bullets at the poles cannot work except for the little boost at impact. What you end up doing is interring all your precious carbon into the ice, never to be seen again.

The idea is that the carbon would react as completely as possible during impact. As you say, anything left over is of only small benefit.

The shape, size and velocity of the "bullets" would be chosen to maximize the reaction. In particular, the bullet would be pre-stresses to fracture into multiple pieces on impact to maximize reaction surface area. Also, if a straight shot didn't give high enough velocity, the bullet could be shot "up" from the equatorially orbiting moon and then arc back down towards the pole at up to 5000 m/sec.

At 3000 m/sec each tonne of carbon would have a kinetic energy equivalent to a tonne of TNT (~4.2 GJ). That's enough to turn 100 tonnes of ice to steam or raise the temperature of 10 tonnes of ice to several thousand degrees. At those temperatures there will be plenty of free oxygen and hydrogen around for the carbon to react with, however, maximizing the reaction rate will require quite a bit of study.

nickname · 2007-07-07 13:10:59

StarDreamer,
noosfractal,

Simple solution to this problem.
We don't compact the carbon on Phobos, leave it in dust format.
Place the dust in carbon shell cases made on Phobos.
Shell cases like that of a very large cannon, then accelerate them to the poles.
The carbon shell cases can be strong enough to survive the trip but to weak to survive all of the re entry to Mars.
Now we would have carbon dust at 3000-5000 m/sec hitting the poles with almost 100% being converted. (well maybe 90%)

nickname · 2007-07-07 18:15:08

m1omg,

I'm not sure about your data for pfc's.

Many types of pfc's and each has a different wavelength it retains heat better at, most of that radiation spectrum Mars has an abundance in.

Are you talking about just 1 of them?
And what one?

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Re: Iceteroids: What happens when they get to Mars?

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Re: Iceteroids: What happens when they get to Mars?

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Re: Iceteroids: What happens when they get to Mars?

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