Terraforming Mars

New Study suggests Terraforming Mars isn't impossible   

Giving Mars an Earth-like atmosphere would be a mammoth engineering task. From giant mirrors to tiny microbes, a lot required to make Mars habitable for humans. This is terraforming, the concept of making a planet more hospitable to humans, and it's been cropping up in pop culture since the early 1900s, everywhere from books to movies to video games. Once upon a time, the idea of turning Mars into Earth 2.0 might have been merely a fanciful notion, as theoretical as actually going to the planet at all. But now, Mars is very much on the agenda. NASA, SpaceX, Virgin Galactic, they all want to put space boots on the ground, and in some cases as soon as the 2030s. Terraforming Mars has been the long-term dream of colonization enthusiasts for decades. But when you start to grapple with the actual physics of what would be necessary to do so, the effort seems further and further out of reach. You might say Mars is a rough neighbourhood. The planet, about 70% the size of Earth, has an atmosphere of mostly CO2 and boasts an average temperature of -81 degrees Fahrenheit (-62 degrees Celsius). Because the atmosphere is so thin (Earth's is more than 100 times denser) there's not much shielding from radiation. 

These conditions pose more than a few problems if humans are planning an extended stay. Terraforming, broadly speaking, would address the creation of a thicker atmosphere and an increase in atmospheric pressure. Getting even more ambitious, it would allow for breathable air. Maybe one day, Martian farmers could work in their shirt sleeves tending to whatever vegetation they've planted in a soil rich with microbes. Mars could be self-reliant for essentials like food and water. Depictions like those of Kim Stanley Robinson's Mars Trilogy are just wildly unrealistic regarding the sheer amount of material that must be moved to the Red Planet to achieve anything remotely resembling Earth-like conditions. This is the conclusion of an abstract presented at the 56th Lunar and Planetary Science Conference by Leszek Czechowski of the Polish Academy of Sciences. The study, titled Energy problems of terraforming Mars, tackles the reality of what it would take in terms of gas to bring Mars up to an "acceptable" level of pressure. As Dr. Czechowski points out, water inside a person's body would begin boiling immediately at the current pressure on Mars, meaning that everyone on the entire planet would have to wear a pressure suit.

There's a solid pile of ideas around terraforming Mars, and they all sound pretty wild. Mostly, they have to do with getting a lot of greenhouse gas into the atmosphere, releasing it from the planet's ice and soil. In 1993, researchers Robert Zubrin and Chris McKay wrote a paper analysing theories for terraforming the red planet. One involved building giant orbital mirrors to reflect sunlight to raise the temperature of Mars, melt the frozen water on the planet and thereby release CO2 into the atmosphere. In another scenario, settlers could build factories whose express purpose is to pump out artificial greenhouse gases like fluorocarbon gases. Humans could maybe harness ammonia-rich asteroids, aligning them to hit Mars. However, certain places on the planet are closer to getting to the pressure level, estimated at about 1/10th Earth's atmospheric pressure, where water would only boil at 50 °C, which is slightly above typical body temperature. The place closest to that pressure currently on Mars is in Hellas Planitia, Mars' "lowland," where the average pressure is about 1/100th that of sea level on Earth, and only 1/10 the amount needed to ensure a person doesn't immediately boil to death if their skin is exposed to the atmosphere.

Then there's the idea from SpaceX founder Elon Musk: Nuke Mars. Musk maintains that lobbing nuclear bombs at the ice caps could melt the ice and put sufficient carbon dioxide into the air. If space weren't a vacuum devoid of sound, though, you might hear screeching brakes in the background right now. It turns out humans can't really do any of this. In July 2018, researchers Bruce Jakosky and Christopher Edwards released a study making it clear that for all the ideas which have been bandied about for decades, humans just don't have the technology right now to terraform Mars. While Dr. Czechowski mentions several other scenarios, such as bringing the average atmospheric pressure on the planet up to that of sea level on Earth, the total amount of atmosphere that would need to be shipped in is an order of magnitude more, which already is extremely expensive in terms of the energy required to realize that increase. Where would we get all this material for the atmosphere? Why the Kuiper Belt, of course. Or at least that is Dr. Czechowski's conclusion. He looked at the possibility of using asteroids from the main belt, which has the advantage of being relatively close to Mars. However, they lack enough water and nitrogen to help build an Earth-like atmosphere. The Oort Cloud, the giant, at this point theoretical, disk that contains billions of icy bodies, has more than enough material to supply Mars's atmosphere.

There's a laundry list of questions to answer: How exactly do you build a giant mirror in space? How do you get access to and redirect the thousands of asteroids needed to sling at Mars? Would it be safe to have anyone on the surface while you do this? How do you build a factory when you don't even have a tent pitched? What happens when you nuke the ice caps, and the gases just refreeze? Furthermore, the study found that even if humans could tap every available source of CO2 on Mars, from the ice caps to mineral deposits, Mars' pressure would only bump up to about 7% of Earth's. However, after some brief calculations, Dr. Czechowski realized it would take 15,000 years to get a reasonably sized Oort Cloud object near enough to Mars to make a material impact on its atmosphere. Impact is the optimal word as well, as the model these calculations describe slams the small body into Mars itself, thereby releasing both its material and a large enough of energy which helps warm the planet. Kuiper Belt objects seem the best fit for this, as they contain a lot of water and could theoretically be brought to Mars over decades rather than millennia. However, they are also very unpredictable when brought close to the Sun. They could fall apart, with some of the material going to waste in the inner Solar System, especially if the technique used to send them into the inner Solar System involves a gravity assist. Such a manoeuvre could tear apart these relatively loosely held-together balls of ice and rock.

"NASA is not currently planning any activities around terraforming Mars," said spokeswoman Kathryn Hambleton. But just because you can't flip a climate change switch on a planet doesn't mean there aren't other ways to alter it, perhaps on a much smaller scope. One idea researchers are looking into is using aerogel to maybe one day build structures like greenhouses. Aerogel is a super low-density solid that's 99% air. It's a good insulator, and NASA's already using it on its Mars rovers. In a study, Harvard University associate professor Robin Wordsworth did an experiment. He shined a lamp set to simulate Martian sunlight on 2 to 3 cm's of silica aerogel and was able to heat the surface below by as much as 150 degrees F. That would be enough to melt ice on Mars. Dr. Czechowski's final conclusion is simple, at least in theory, we can get enough material to dramatically increase Mars's atmospheric pressure to a point where it is tolerable for humans, or at least to a point where they don't die immediately when exposed to it. However, doing so will require us to crash a sizeable icy body from the Kuiper Belt into it. To do that, engineers would need to design a propulsion system which doesn't rely on gravity to direct the icy body. In the conclusion, Dr. Czechowski suggests a fusion reactor powering an ion engine but doesn't provide many details about what that system would look like.

Taking a more controlled approach could help address some of the ethical considerations around terraforming, like whether humans have the right to alter and, let's be real, potentially screw up an entire planet. Planet wide terraforming would likely wipe out whatever evidence of life we haven't found, or even just the geologic record of the solar system we no longer have on Earth. There might be other methods to terraform Mars which involve bioengineering, but they would still take an absurd amount of energy. Given the technological requirements needed to achieve that vision, it seems we're a long way off from doing so. But that won't stop Mars enthusiasts from dreaming of a terraformed future, even if it does involve smacking the planet with multiple large rocks to get there. There's so much more we have to learn about, like pristine Mars as it is, before we are going to change it. Though a terraformed Mars isn't something anyone alive today will live to see, but it could still happen. The fact anyone can conceptualize even theoretical ways to terraform Mars means it'll be plausible in the future. In fact, in 100 years, humans might just be techie enough. Progress in biotechnology, nanorobotics, maybe there will be bioengineered plants which could put out far more oxygen than the ones on Earth. Relying on the technological sophistication of future humans.