Can we really terraform Mars? New study outlines a plan and the challenges

From the pages of science fiction to the fringes of reality, Mars has come a long way. Rovers that roamed around the red planet changed our perception of it. Now, astronomers conceive grand plans to land there, build a human base and gradually make it habitable. A new paper published on the arXiv preprint server by planetary scientist Edwin Kite of the University of Chicago and his co-authors suggests possible ways to terraform Mars. They focus on a three-stage process. The first is to build greenhouses. These are not like the ones that one encounters in the cold north on Earth. The ones proposed for Mars will be made of silica aerogel. These houses have specially designed canopies that will let sunlight in but trap infrared light. This process will gradually increase the heat inside the houses.    

One by one, these houses will create warm oases and eventually cover the whole planet. Inside the domes, heat will melt subsurface ice already present on Mars, supplying water for the residents and supporting pockets of human life. Next, the researchers suggest harnessing more solar energy directly on the planet. To do that, massive solar sails acting as orbital mirrors can bring additional sunlight down. Initially, it could be directed toward the place where humans live. Gradually, this process can be applied globally to warm the planet.  

On a planetary scale, such beams of sunlight could also sublimate the vast carbon dioxide deposits at the Martian South Pole and release this gas into the atmosphere. This, in turn, thickens and warms the atmosphere. But solar sails are too heavy to be economical. The researchers calculate that engineers would have to build solar sails on a mass scale. Each square meter of the solar sail should weigh less than 20 grams. It is probably a third of the weight of the current best material that we have.  

The third process speaks of an even more dramatic way to increase the Martian temperature. It suggests the use of engineered aerosols. The researchers note that highly specific nanoparticles like aluminum nanorods or nitrogen-doped graphene can be released into the atmosphere. They estimate that 3 million tons of such nanoparticles are needed to make a visible global effect on Mars. They also calculate future cost, which is around $2000 per kilogram. We need to make such a material on the red planet. 

How will we make such materials on a planet that is extremely inhospitable to life and at every step, we need life support? On top of that, Mars is, on average, 140 million miles away from Earth. No immediate human help is possible since space missions that, so far, reached the planet took between seven and ten months. It seems that the plans are far from reality. But the researchers note that warming at the kilometer scale is at least a decade away. This sort of optimism will keep the option of extending life beyond Earth open. 

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