New Mars Forums

Setting off nukes in the Sahara desert.  As if the Arab world didn't hate the west enough.   

Regarding the fusion bombs, I was under the impression that the radioactive fallout of modern fusion weapons was negligable.  You still need to kick off the fusion with some fission but I thought the total of fallout was like getting an x-ray or something.

This is a long post so brace yourself.  Also, there’s some crackhead math in here to correct me if I’m wrong.

First, I was thinking about reducing the CO2 to CO with an iron asteroid.  The reaction that I found was with molten iron so I don’t even think dropping an iron lump into the atmosphere would do the trick even if it were dust.  Even if it could reduce the CO2 into CO, I don’t see a need for that right away.  A sunscreen will take care of the heat problem.  Also, locking away all that oxygen seems like a bad idea to me.  If we do import hydrogen we’d get two molecules of H2O for a CO2 molecule as opposed to a single one for a CO molecule.  The more water the better in my opinion.  Plus, I don’t think that crashing iron asteroids would yield a dust cloud.  I’m inclined to think that they might fuse or just break up into dump truck sized particles that would just crash to the surface.

Now back to the L1 comet idea.  Keeping a comet positioned at L1 might be a hard thing to do.  Sending the comet toward Venus might be “easy” but breaking it to stop at a particular point in space sounds tough.  Even if we could do some magic with a gravity de-assist around Venus and swing it into L1, you would have to constantly correct its position.  L1 is unstable to begin with plus the comet will be changing mass and spouting geysers and points of thrust minute by minute.  I suppose you could keep it in place with some kind of giant net attached to some craft.  They could adjust its position to keep it in place but that might be difficult to impossible.

Another alternative would be to just put them into orbit around Venus.  It seems easier to insert them into some kind of orbit rather than halting them at L1.  If you could have 4 or 5 in orbit you would still get pretty good coverage.  After they burn out, you could leave them where they are and mount magnets and solar sails on them to block solar wind and light. 

Now according to my old math, you’d need 3.8 x 10^19 kg if H2 to convert all the CO2 into water and C.  I looked up some info on Halley’s comet and if you assume that we can wrangle similar objects they would each contain about 2.45x10^15 kg of water.  Only 1/9th of that would be H so each comet would contain about 2.7x10^13 kg of hydrogen.  That means you’d need 100,000 (or 1 million if I’m off by an order of magnitude) Halley’s comet type objects to provide enough H to convert the atmosphere to water and graphite.  Lumping together that many burnt out comets would make a nice moon but getting that many to Venus sounds impossible to me. 

In short, I think the comets will act as great sunshades but whatever hydrogen they add won’t be significant.  This also tells me that you’d need something like 10,000-100,000 comets to get 10% of the Earth’s water to Venus.  Getting that many there would be tough and crashing them there would devastate the surface.  Pure hydrogen importation looks like the only feasible option to get water onto Venus. 

That will still take a long time and probably involve founding a gas-mining operation on the outer gas giants but it seems to me that it’s the best way to go.

So let’s assume that you import all that hydrogen and you get a 3 bar nitrogen atmosphere with enough O2 and CO2 to support plant and animal life.  UV light would still be a problem but couldn’t we construct an ozone layer to block that out?  Sulfur would be a problem but I agree with REB that a water cycle would eventually wash all the acid rain out of the atmosphere.  Failing that, I’m sure that anything else we would need could be gotten from the planet itself.  If we need to fix oxygen or sulfur with iron or calcium, we could just dig for it pick-and-shovel style and send it up into the atmosphere via balloon, catapult or smokestack.  No need for nuclear rockets strapped to planetoids that take 50 years to arrive. 

I think the plant life thing will be interesting.  There are plants grown in the artic circle that get as big as a car because of the 6 month day.  I think certain plants would just go into a 4 month growth spurt during the day and go into winter mode at night.  Actually, that’s a much simpler arrangement than what they have now.  On earth, they have to deal with patterns of light and dark embedded into a cold/warm cycle.  Since Venus’ axial tilt is virtually 0 it’s likely that there will be no seasons, just day and night. 

Chat, water is a funny greenhouse gas.  It can trap heat or reflect it depending on its form.  Since no one knows for sure what the temperature range would be on a stable Venus, it’s hard to tell what the water’s effect would be as a greenhouse gas.   That also leads into another realization I had.  All the methods we’ve talked about so far deal with getting Venus 90% of the way to habitable.  I think that last 10% is going to be the killer.  The difference between an average planetary temperature or 15C and 35 C is only 20 degrees but it could drastically change the climate of the place.  I think it’s the fine tuning that will be the really touchy part after all the comets, hydrogen, sunshades, L1 magnets, moonlets and biosphere are put into place.

The SO2 in the atmosphere would be a bitch to deal with.  The more I look into this, the more terraforming Venus looks like large scale chemestry.

I found a way to get a sulfur snow http://jchemed.chem.wisc.edu/JCESoft/CC … 1.HTM]here.  If you sprinkle calcium oxide CaO into the SO2 clouds.  It's a 1:1 reaction but the SO2 would precipitate out of it's gas form and fall down to the ground.  Of course the temperature, moisture and wind could mess up the whiole reaction but it seems like sulfur fixing wouldn't be overly complicated.

Eternal,

You posted that:

Does that mean that the acid is on both sides of the equation and just acts as a catalyst?  In any case, you would have to ship trillions of tons of carbon and oxygen that you could already find on Venus.  Also, that's a lot of sugar for Earth to supply.  I don't think all the bees in history could produce enough.  Why not just ship the hydrogen?  You get a 9:1 return of water to hydrogen.  I'm no chemist so please correct me if I'm wrong.  Also would this add heat or suck it up?

Would a ring around the world do anything to speed up it's rotation?  I can't see how it would.  Same thing with a moon.  A moon might try to get it into tidal lock but unless it's very massive, that would take a long time.

I'm against shipping gasses interplanetary except in the cases where you have no alternative (nitrogen to mars) or hydrogen because of the aforementioned high yield of useful stuff like water.

chat,

I love the idea of using the burnt out comet cores to build a moon system.  Again, I don't think they'll be of any use as a world spinner but if you built huge mylar sails on them, they would act as decent sun shades and full moons for the night side. Not perfect shades but on a wet Venus a full shade might not be needed.  If you had about 10 of them in orbit it wouldn't matter that they would be moving around the planet rather than at L1.  Besides, I don't think an L1 moon would be doable because L1 objects have to be constantly adjusted to make sure they don't land on Venus or the sun.

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Here's my latest crazy plan.  I'm still all about hydrogen bombardment of venus to clear the air and make oceans.  The bottleneck is getting that much hydrogen from the gas giants.  My first plan was to use tanker ships that dove into the atmosphere to scoop up the gas and go back to Venus.  It might be a bit tricky to make ships that big that can handle that kind of stress.

So what about a space elevator in orbit of a gas giant?  It wouldn't have to be long enough to touch the surface, just skim the atmosphere.  It also wouldn't need to be in geosynchronous orbit.  You would pump or ship gas up to a space station at the top of the elevator and tankers could pick it up at the top and cart it off.  Here's the best part:  you could mine He3 in the process both to fund the effort, make a profit and provide energy for the pumping/shipping and the tanker ships.

This of course assumes carbon nanotubes, monster tanker ships and second generation fusion but it's a nice way to mine hydrogen.  Hey, I think I may have invented http://www.starwars.com/databank/locati … html]Cloud City

I'm working on getting that comet heading to the Venus/Sun L1 point. 

I just did a bit more reading on comets and I think the comet at L1 idea might be better than I thought.  aparently the tail of a comet can have a diameter of thousands of kilometers.  That sounds like it's big enough to cover most if not all of the sun-facing side of venus.  so there's a cheap sun-shade.

I also read that one component of a comet's tail is a hydrogen jet!  The UV rays break up the water as it boils off and the hydrogen blows away from the oxygen.  So the comet will blast hydrogen at the atmosphere with no help from us.  That would react to start making water and graphite and by the time the comet was gone, Venus might have enough surface water to start reflecting a lot of sunlight on it's own.

by the way, will a sunshade be needed if venus had earth's atmosphere?  Will the shade just be a temporary thing while the atmosphere is cooled and processed?  If not, it just seems like a matter of dragging a few comets in front of venus, waiting and pushing off the rocky cores when we're done.

Rock! :band:

I haven't read back all the way in the thread but has anyone considered cloning?  just freeze a bucketful of genetic data and you can clone up hundreds of species per ark-trip.

You may have to bring a couple of host animals intact to act as a surrogate mother but that's better than launching a zoo.

Bringing sperm and eggs would probably save a lot of space too.  I saw a show on cow breeding and most if it is done that way anyway in the industry.  There are only a handful of "daddy cattle" in the industry.

ok, new idea.

If we're assuming we can push comets around why not just park them at the sun/venus L1 point?  they will act as sunblocks and the comet's tail will increase the affect.  All the stuff blown off of it will land in the atmosphere so we can add water without crashing it directly.

so we get the water, we get a partial sunshade and we don't have to damage the crust in the process.

thoughts?  anyone know how big a comet's tail would get that close to the sun?

nuclear blasts or comet impacts on the poles would kick up dust onto the poles.  likewise soot factories placed near the poles would darken them without having to truck dirt all over the place.

I've thought about the soletta a bit.  to work it would have to have a diameter larger than Mars.  Otherwise, it wouldn't catch any light that would miss the planet.  KSR had a big aluminum foil structure. 

It seems to me like something that massive yet flimsy would be prone to failure.  Not to mention the difficulty of making it in the first place and it had moving parts.  KSR just threw some robots and an asteroid together and *poof* soletta.  Personally, I don't think it would be that easy.

One alternative for a quick and dirty solleta would be a web of M2P2 thingies at a modified L1 point.  Let's say you have 2 big solar powered electromagnets bound together and you place them at the L1 point.  You could spin them then start reeling them outward from one another on a long tether.  It would have to be something like 5000km but let's assume we have something like carbon nanotube fibers that could handle it.

So now you have a line segment spinning clockwise (or counterclockwise) in front of the sun with electromagnets at the endpoints.  Now you fire up the electromagnets and sprinkle some charged aluminum dust in the magnetic fields.  Assuming you can make the field large enough, you effectively have a big mirror on each end.  If you angle it correctly, you would see the sun flanked by two "sunlets" rotating around it from the surface of the planet.

Now just scale up and add as many line segments as you can near the L1 point and the Sun will have a necklace of reflective disks increasing the amount of sun hitting the surface.

Seems a lot easier to construct than a foil-based structure.  You would have to deal with the push from solar wind and light pressure but you would just place it a bit sun-side to compensate.  The dust would be lost after some time but you could just send up a craft with a few tons more every now and then.

Well, I guess the things that come to my mind are:

- L2 mirror to melt to poles (M2P2 or Mylar).
- pump lots of PCFs into the atmosphere
- crash comets to bring water and other stuff
- nuclear bombardment of the poles
- soot factories to inclease the albido
- electromagnet(s) at L1 point to block solar wind
- importation of nitrogen from titan
- importation of hydrogen from the outer gas giants
- concentrated sunlight lasered out from inner solar system
- introduction of plant/incect life

Some of those are "easy", some are long term, some are well agreed upon and some are my own crazy ideas.

I did some quick crack-head math and 20ppm of water works out to about 1/131,000th the amount of water on Earth.  Can someone correct me if I'm wrong?

I was taken aback when I heard that too because the books seem to glorify the terraforming effort and describe the reds as lunitics. One of the main characters Sax is the lead terraformer and he's cast like a geek-hero.  Maybe that's just my slant as a green.

Fair enough.  I'm no expert on fiber optics.  I still think that it's more productive to gather the light closer to the sun.  Would it be possible to forgo the fiberoptics all together and just bounce the focused sunlight back with a curved mirror?  You could have a small hole in the bottom of the sun-facing mirror to allow the focused beam to reflect through.  Would it be possible to focus and direct it using light mirrors and lenses?  You would still need to make them smart to point to mars accurately but if Hubble can do it, so might these things.

Or should I just let this one die?

Alternatively you could mount the whole rig on a large body like the Moon or Mercury but you get the issue of them not facing Mars all the time.  That and a planetary quake could take them all out if they are unmanned.