We’ve heard the news: Elon Musk wants to send us all to Mars. For $500,000 each. At a rate of 80,000 a year. Opinions are scattered -- is he visionary? Is he crazy? But for the more curious among us, another question has come up: how do you build a human-safe colony on Mars? And how is Elon Musk planning on doing it?
If you want to get to Mars for $500,000 a person, the first thing you need is a reusable rocket. “Even partial expendability would blow up that price tag.”
So Elon Musk, of course, is working on building a reusable rocket.
What’s he got so far?
Well, there’s the Falcon 9, which is Musk’s currently proven, though not fully reusable, rocket. And the Falcon Heavy, in development, which is much bigger -- "made up of three nine-engine cores, which are used as the first stage of the ... Falcon 9 launch vehicle," according the SpaceX website. But neither of those are fully reusable rockets. The closest Musk has come is the test craft “Grasshopper”, a fully-reusable rocket capable of vertical takeoff and landing. Thus far, the Grasshopper has only done two experimental test flights -- one to a height of six feet and one to a height of 17.7 feet. Both test flights were successful, and the “Grasshopper” has still not needed replacement.
But Musk may have some competition. A British company, Reaction Engines LTD, has recently announced that they have plans for an engine that, according to Reuters, “...would operate like a jet engine in the atmosphere and a rocket in space, [and] could displace rockets for space access and transform air travel by bringing any destination on Earth to no more than four hours away.”
The engine has not been built yet, but Reaction has successfully tested the technology that would make such an engine possible: “a remarkable heat exchanger that is able to cool air sucked into the engine at high speed from 1,000 degrees Celsius to minus 150 degrees in one hundredth of a second.”
Could such an engine be adapted to Musk's needs? Musk says that his fuel of choice for a Mars mission would be methane; it’s cheap, easy to deal with and unlike hydrogen, the other fuel he considered, it’s not prone to “invisible high-temperature fires.” Moreover, methane can be produced on the surface of Mars as a byproduct of producing breathable oxygen from the planet’s frozen carbon dioxide and water ice.
The first Mars settlers, Musk says, would likely live out of their spacecraft after landing, hence his reluctance to consider the tiny Dragon space capsule a viable Mars landing craft: “It’d be like living in a minivan for two and a half years.” Instead, Musk plans on building an enormous, house-like craft for this mission: according to Space.com a “huge new reusable rocket which is rumored to bear the acronymic name MCT, short for Mass Cargo Transport or Mars Colony Transport.”
But the spaceship would be more than just a home: it would also be a lifesaver. Remember our big old atmosphere, that thing that means we don’t need pressure suits and protects us from deadly space radiation? Outer space has no such atmosphere, and astronauts on long spaceflights quickly develop a wildly increased risk of getting cancer. The solution? Musk has discussed “using the spacecraft’s liquid water store as a barrier between the Mars pioneers and the sun.”
Groundwork for the Martian home would begin with a focus on building transparent domes pressurized with CO2, while possibly covered in a layer of water to serve as protection from the Sun. Additional trips to the Red Planet would bring equipment that could help to produce fertilizer, methane and oxygen using the atmosphere’s natural elements of nitrogen and carbon dioxide.
Much has been said about how Musk wants to start a “vegetarian colony on Mars," but really, what could the first Martian settlers be besides vegetarians? Meat is an inefficient use of hard-to-grow vegetables, farm animals are likely a pain on spaceships, and really, where are you going to find meat native to the red planet? Farming is the way to go -- especially if, as Wired proposes, you can now 3D print the necessary tools straight from the planet’s soil.
And that’s how we get to terraforming.
Last but not least, if Mars were to become a truly earthlike environment, it would need to be terraformed. Says Musk, "you need to live in a dome initially but over time you could terraform Mars to look like Earth and eventually walk around outside without anything on.” But as of now, Musk has remained silent on how he expects terraforming to proceed.
Still, experts say he’s right to be hopeful. Experiments have revealed that algae can grow in environments only slightly altered from Mars’s current state. And scientists say that it will only take a little mankind-induced global warming to create an atmosphere suitable for heartier plant growth. Explains WiseGeek:
The current average temperature on Mars is -51°F (−46°C), with lows of -125°F (−87°C), meaning that all water and much carbon dioxide is permanently frozen. The easiest way to raise the temperature seems to be by introducing large quantities of CFCs — chlorofluorocarbons, a highly effective greenhouse gas — into the atmosphere, which could be done by sending rockets filled with compressed CFCs on a collision course with Mars. After impact, the CFCs would drift throughout Mars' atmosphere, causing a greenhouse effect which would raise the temperature, leading CO2 to sublimate and further continuing the warming and atmospheric buildup.
Even a warmed-over red planet may take years or even decades to develop into a fully earthlike environment -- but with settlers on the surface, plants in the ground, and an atmosphere growing in the sky, it’ll be a a far cry from the “fixer-upper of a planet” that Musk sees now.
CORRECTION: A previous version of this article cited Talking Points Memo as saying that the Falcon Heavy rocket consists of two Falcon 9s strapped together. According to SpaceX's website, in fact 3 Falcon 9 cores comprise the Falcon Heavy.