Stephen Petranek’s book How We’ll Live on Mars successfully takes what the general public perceives as science fiction and transforms it into science fact. Our native planet teeters in fragility between the threats of environmental ruin, nuclear warfare, asteroid collisions, and inevitable demise at the hands of our own sun. Humans need to find a second home and then, Petranek asserts, “we must become a spacefaring species”. This book proves we are much closer to colonising Mars than the general public may think; the little red dot in our sky, up to 250 million miles away, will be our next home. For Petranek, and many aerospace scientists, this is not a matter of if, but when. The often asked questions about oxygen, radiation, food, and water are all adequately quelled by Petranek’s thorough examination of the technology that is already available. Shockingly, according to Petranek, we have been capable of going to Mars “for at least thirty years”.
Petranek goes on to ask what hindered our progress, which seemingly ground to a halt after Apollo made it to the moon in 1969. The very rocket that got NASA there, the Saturn V rocket, was designed by the infamous German rocket scientist Wernher von Braun, who implored NASA to head to Mars next. Von Braun wrote the gold standard manual ‘Das Marsprojekt’ in 1952, detailing how a fleet of spaceships built on a space station—like the ISS, built later on—could make their way to Mars. He devised the ‘Hohmann transfer orbit,’ a fuel-saving method for a spacecraft. Using this method, a spacecraft would coast until it is brought close enough to Mars that a short burn of the engines would be enough to take it into orbit. President Nixon denied von Braun’s proposal, and instead directed NASA’s focus towards the Space Shuttle Program – which likely benefitted the USA’s military and intelligence agencies.
The author calls the ISS “a pretty useless hunk of technology,” and makes it clear that NASA has been nothing but underwhelming. The 135 space shuttle missions, costing $1 billion each, are scarcely justified by the little scientific progress made. Chapter 2, ‘The Great Private Space Race,’ outlines the numerous private companies that have sprung up in the last 30 years or so with the aim of getting humans to Mars. Some are promising, others not so much. The most plausible among these companies thus far seems to be SpaceX, founded by Elon Musk. Petranek imagines humans stepping foot on Mars by 2027, and envisions the spacecraft landing on the red dust to be sporting the SpaceX logo, not NASA’s. Elon Musk is our generation’s von Braun; Petranek says he is “a perfectionist who is convinced of his vision and determined to achieve it”. When Musk’s Dragon capsule reached the ISS in 2012, the world realised how serious he was.
Chapter 4 addresses common questions about the colonisation of Mars and the rest of the book delves deeper into how it could work. From spinning spacecraft to simulate gravity on the voyage there, to combating cosmic radiation with water insulation (as proposed by Musk), no problem is downright confounding according to Petranek. The biggest obstacle is not technology, but how much money we are willing to pour into what is, essentially, a life insurance policy. The key to making it affordable is designing reusable rockets, as von Braun planned to. For example, launching SpaceX’s Falcon 9 rocket could go from costing $60 million to $60,000 – just the cost of the fuel. Once we get there, though, how will we fare?
Mars has a thin, toxic atmosphere which provides no protection against solar or cosmic radiation, and has no known liquid water (although NASA’s Pheonix craft showed that Mars’ ice caps likely contain over 1 million cubic meters of frozen water). How can such a world be habitable? Petranek is clear that terraforming Mars, i.e. “making Mars in Earth’s image,” is the long term goal. He simplifies the overall strategy scientists will employ to terraform the red planet: warm Mars to melt the ice. This will release frozen greenhouse gases trapped in ice caps, producing a denser atmosphere, which will warm the planet (and provide protection from radiation). Further ice will melt, thereby hydrating the soil and allowing plants to grow. Plants will then gradually oxygenate the atmosphere (although this could take over a thousand years).
The creative solutions to setting this plan in motion are astonishing. Petranek presents the work of countless researchers working towards this goal; from solutions as small as genetically modified bacteria and plants, perfect for the Martian soil, to giant satellites reflecting sunlight to melt Mars’ polar ice caps, and everything in between. In fact, scientists have already simulated planting on Mars: when using emulated Martian soil in a greenhouse, all the tested seeds germinated. However, Martian-grown food would only be a small part of the diet, with humans still relying on Earth-imported produce for over 90% of their food supply. Furthermore, before the atmosphere becomes breathable, oxygen will have to be made from the electrolysis of water, which consumes a great deal of electricity. To fuel this, solar panels and small nuclear reactors will be required.
Humans will have far more problems than just food and water, however – simply walking outside into the Martian environment would be a challenge due to its thin, toxic atmosphere. Flexible pressurised spacesuits are being designed for this very purpose, to allow the new Martian inhabitants to venture outside of sheltered buildings and explore their new territory.
Petranek likens the brave future pioneers of Mars to Ferdinand Magellan, who initiated the first, treacherous circumnavigation of the Earth 500 years ago. In doing so, he expanded our horizons. “A voyage to Mars will make the Age of Discovery look like a minuscule event in human history” – this book highlights that we are on the cusp of a new age. It emphasises that setting our sights on Mars should not mean neglecting Earth, however. Indeed, Petranek states that “We must work desperately and devotedly to save our home planet.” The technology being engineered to transform Mars into a home could save our own.
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