Would You Live in a City on Mars?

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The International Aeronautical Congress (IAC), held on 27th September 2016 in Guadalajara, Mexico, will see SpaceX CEO Elon Musk give a presentation entitled “Colonizing Mars – A deep technical presentation on the space transport architecture needed to colonize Mars”. Musk is expected to announce the highly anticipated Big Falcon Rocket (BFR – formerly Big F***ing Rocket) and the Mars Colonial Transporter (MCT), before setting out the company’s plans for eventually establishing a viable colony on Mars.

SpaceX was founded after Elon Musk made his fortune from co-founding and eventually selling PayPal to eBay for $1.5Bn – with Musk receiving $165 million. Unlike most Dotcom success stories, this one was just beginning. With $100 million of his fortune, Musk started SpaceX in June 2002 with the aim of colonising Mars and making humans a “true spacefaring civilisation”. Despite splitting his time with the equally revolutionary Tesla car company, Musk has overseen the growth of SpaceX to become the first ever private company to put a satellite into orbit (2008) and to supply the International Space Station (2012).

Since then, SpaceX has become the largest private producer of rocket engines in the world, with engines such as the Merlin 1D, which has the highest thrust-to-weight ratio of any known rocket engine. Likewise, they have continually pushed the boat out with other ground-breaking technologies like the first ever recoverable rocket first stage – landing vertically on an autonomous ship in the sea. This astonishing feat is quickly becoming the new mundane as (at the time of writing) six out of eight attempts have been successful – meaning a dramatic reduction in the cost of space flight is around the corner.

But why spend all that money on colonising Mars? Haven’t we got bigger fish to fry at home? Well, yes and no. Musk often describes the reason thus: Why would you make a backup of a hard drive but not of our entire civilisation? Given the ‘existential risks’ posed to us by things like asteroids and super-volcanoes, along with more pressing threats such as nuclear wars, engineered super-viruses, runaway global warming or the invention of true Artificial Intelligence, many people believe a self-sustaining colony on another planet is just plain, prudent common sense – and this is even before mentioning something as terrifying as the Great Filter response to the Fermi Paradox (more details in the Jargon Buster below).

The BFR itself has to overcome huge challenges in order to be able to launch a large vehicle to Mars. Sending a crew to Mars would involve launching a space shuttle-like mass into space 50% faster than required to put a satellite into low Earth orbit (LEO), cruising to Mars over the course of about six to nine months, all before slowing down from a speed of 5.7 kilometres per second (or about 12700 miles per hour – i.e. 7 times faster than a speeding bullet) to land safely. And as if that weren’t hard enough, it then has to take off from Mars and fly all the way home – something which has never been done before.

To achieve this, SpaceX will utilise methane fuel since it can be made on the surface of Mars with relatively simple and well understood chemistry. It is speculated that it will fuel a rocket weighing 5000 tonnes capable of carrying a 100 tonne payload, with three cores of 13 metres in diameter and a thirty storey total height. It will use 34 rocket engines for a peak thrust equalling that of eighty Boeing 747 jumbo jets – twice the thrust that the famously enormous Saturn V rocket produced.

SpaceX Rocket Size Comparison. Credit: Sebastian Steele
SpaceX Rocket Size Comparison. Credit: Sebastian Steele
Nerdy Numbers Speculation For Nerds (Press me!)
Total mass:    4600 tons + 100 tonne payload
Engines:    31 Raptor engines (BFR), 4 Raptor Vacuum Engines (MCT)
Peak thrust:    71,300 kN (BFR)
Stage delta-v:    3.044 km/s (BFR), 6.879 km/s (MCT)
Core Diameter:    3x 13.4 metre
Height:    ~80 metres with 13.4m core, or up to 130 metres with thinner cores.
Source: User RulerOfSlides on Reddit: BFR/MCT: A More Realistic Analysis, v1.2 (now with composites!)

It is only with the context of existential risks paired with Elon Musk’s remarkable track record that SpaceX’s plans seem not only reasonable but achievable too. In any case, this wildly ambitious plan largely relies on bringing down the cost of space travel to the extent that the intersection of people who can afford to go to Mars and those who want to grows significantly. If, indeed, this really happens, I, like so many others, may well be able to fulfil my dream of visiting a whole other planet.

 

Jargon Buster

  • A rocket operates on a similar principle to that of a jet-engine: Expand a lot of gas through a nozzle to create a jet of gas which propels the craft forwards. A conventional rocket engine combusts on-board liquid oxygen and a fuel, stored in tanks.
  • Conventional rockets are often split into multiple different sections or “stages”, each composed of a fuel tank and a rocket. As the fuel drains the stage is released and dropped back to Earth, saving weight. Each stage’s rocket may also be designed to be most efficient in certain conditions, for instance at low-altitude or in space.
  • A global catastrophic risk is a hypothetical future even that could damage human well-being on a global scale. Any event that could cause total human extinction is also known as existential risk. Such events may include nuclear war, climate change, asteroids or hostile artificial intelligence.
    On a lighter note, I found this line on Wikipedia entertaining:
    ‘Researchers experience difficulty in studying near human extinction directly, since humanity has never been destroyed before.[4]’
  • The Fermi Paradox, named after physicist Enrico Fermi poses the question that, despite the huge number of potentially life-supporting planets in the universe, we have not found any evidence of alien civilisation. Given a rough number of ~10^23 stars in the universe (that’s 1 with 23 zeros after it. In other words, there are 10,000 stars for every grain of sand on Earth), and given perhaps 5% of them could support life, 22% of which may be Earth-like, there should be roughly 100 billion billion Earth-like planets in the universe. That is, there’s 100 Earth-like planets for every grain of sand on Earth. Keep going with the numbers and there could be 100,000 intelligent civilisations in our galaxy. So why haven’t we heard from them?
    There are broadly two groups of explanations for the Fermi Paradox. Group 1 is the “Great Filter” I mentioned. It suggests that there could be a significant wall that most or all attempts at life hit. It could be in our past, for instance life beginning at all or the jump from single-celled to multi-cellular life – suggesting that we are exceptionally rare – or it could be in our future, for instance a regularly occurring explosive interstellar event like a gamma ray burst or a supernova destroying us, or a man-made technology (like AI) wiping us out. These could either prevent a civilisation from progressing because they were too slow to expand from their host planet or system, or it could be that nearly all civilisations who tried to make a certain technology were killed by it.
    Group 2 suggests that there are logical reasons for not having seen evidence of alien life. There are several possibilities, such as aliens visiting before the 50,000 years for which we have existed; our technology being too primitive to listen to any activity that is going on; higher civilisations being aware of us and observing us (the “Zoo Hypothesis”); or that we are not advanced enough to even perceive their activities, just as an ant cannot understand what a skyscraper is.
    In any case, Elon Musk, like many others, believes that the sooner we back-up humanity the more likely we are to survive any potential “Great Filter” events.
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Third year Mechanical Engineering student. Wessex Scene's Science Editor and last year's Head of Design. Interested in cars, AI, virtual reality, etc. etc.

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