The comet impacts would not only melt the poles but add their own water mass to the environment as well. If we were to employ nuclear weapons to melt the poles there would be the side effect of a radioactive "dead zone" which could last for millenia (if not longer). At the very least we would introduce radioactive fallout into the Martian environment, since at the heart of any H bomb there is a Plutonium or Uranium trigger that would leave some "dirty" effects behind.
Teh important thing to do is ADD water to Mars so you could use it to help thicken the atmosphere when it evaporates.
In a magazine article (the title escapes my memory at the moment) terraforming Mars is discussed in some technical detail and part of the scenario was using comets to increase the water mass. Then factories which produce large ammounts of CO2 as a by product woudl be set up with the workers (humans) living in bio-domes or underground. Large solar mirrors in orbit and on the ground would help raise the temperature.
When an atmosphere of CO2 reached a barometric level simmilar to the high alpine regions of earth high altitude connifers could be planted adn start the CO2 - O2 cycle as the factories and humans continued to produce CO2. Eventually the humans would be able to venture out onto the Martian surface with less and less protective equipment. They could go from full pressure and temperature suits at the start of the program to low pressure thermal suits within a few decades and then within 200 years people could walk on the surface without any protection at all, except durring winter.
My timeline may be a bit off from the article (I'm going from memory here) but as we approach the "singularity" we coudl develop new technologies that could concievably speed up this process to take a total of a few decades. The initial timeline is assuming we use the technology we have available today. The main innovations that are needed to get the ball rolling are transport infrastructure (getting there and back efficiently), habitation (where the people live while this is going on) and life-support (efficient methotds for generating food, water, air and electricty). Economy is something I'll leave up to... economists.
The other concerns raised are worthy of consideration but pointless if the task is too daunting or restricted by paranoid governments affraid of humanity getting out from under their thumbs. = ) Even if private industry wants to and can afford to do it, current governmental controls (especially those imposed by the US) must be lifted or nothing will be allowed to happen. If a government doesn't want something to happen, it's damn hard to make it happen, they have the power and the guns to back themselves up.
Just my two cents....
Clint O'Dell wrote:
> >To give it a big boost all that is required is a few comet diversion
> >missions. The added heat and evaporated gasses will give a big boost to
> >the system, especially if they are dropped on the poles.
> What about nuclear weapons? wouldn't that would be cheaper?
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