Updated 10:00 a.m. EST, Wednesday, November 28
SpaceX founder Elon Musk has caused quite the commotion in recent days with his proposal to create a human colony on Mars, first unveiled in some detail during a November 16 talk at the Royal Aeronautical Society in London, UK.
But after news reports of the talk quoted Musk as saying he’d like to send 80,000 people to the Red Planet in the not-too-distant future, Musk himself upped the ante: Taking to Twitter on Tuesday, the charismatic multi-industry entrepreneur (Musk also founded Tesla Motors and Solar City, and before that co-founded PayPal) clarified that he actually planned to send 80,000 people to Mars every year once the colonization process begins, for a total of millions of human settlers on Mars.
“Millions of people needed for Mars colony, so 80k+ would just be the number moving to Mars per year,” Musk tweeted on Tuesday afternoon, linking to a Yahoo News re-post of an earlier Space.com article that quoted the SpaceX founder.
“And, yes, I do in fact know that this sounds crazy,” Musk tweeted, immediately following. “That is not lost on me. Nor I do think SpaceX will do this alone.”
“But if humanity wishes to become a multi-planet species, then we must figure out how to move millions of people to Mars,” Musk continued.
Musk’s Mars colony proposal is still a long way to commencing and lacks many key details on just how it would work, but based on what the entrepreneur has revealed about his plans so far, here’s what we know about how he and his collaborators would even go about pursuing such a colony, given no humans have even visited Mars temporarily yet:
Reusable rockets are key
Musk has been repeating this refrain for a while now and did so again in his talk to the Royal Aeronautical Society (video below), but it bears repetition because it is arguably the most important intergal step in getting a Mars colonization plan together.
“I think it’s a pivotal step on the way to establishing a self-sustaining civilization on Mars,” Musk said during his talk, regarding reusable rocketry. “If we don’t do that I don’t think we’ll able to afford it, because it’s the difference between something costing half a percent of GDP and all of GDP.”
“The reason to be able to do the vertical landing is because we’re aspiring to achieve a breakthrough that is extremely important for rocketry which is rapid and complete reusability,” Musk said during his talk (9:55). “It’s important that it be both rapid and complete — like an aircraft or a car, or a horse, or a bicycle. Even if you had to repaint a plane between flights you’d currently more than double the cost of the ticket.”
SpaceX has been working toward the goal of a fully reusable rocket by using technologies that it has already proven to be successful — namely its Falcon 9 rocket and Merlin engines, which powered two flights to the International Space Station earlier this year and the company has incorporated into a new test craft called Grasshopper, which is designed to perform vertical takeoff and vertical landing (VTVL). SpaceX has tested the Grasshopper craft twice in late 2012 so far, performing two complete “test hops,” at its site in McGregor, Texas. Below is video of the latest, in early November.
“It’s not going to happen overnight, but we’re going to keep going in that direction until ultimately its as close to aircraft-like dispatch capability as one can achieve,” Musk said.
The main reason Musk thinks that reusable rockets are the ticket to a Mars colony, and other forms of space exploration, is because of the massive reductions in the cost in space travel such a capability would confer. As Musk put it in his talk:
“The cost of the propellant is only about 0.3 percent of the cost of rocket. And we have a low cost rocket….The Falcon 9 is 60 million dollars, and that’s for something with four times the thrust of a 747 and about the same liftoff mass. So that’s a good deal. But the propellant is only 200,000 dollars. So if we could use the — hypothetically use — Falcon 9 rocket 1,000 times, then the capital cost would go from being 60 million dollars per flight to 60,000 dollars a flight.”
Musk said that he was “hopeful we can start to bring back the first stage back in the next year or two,” while full reusability would be 5 to 6 years away.
Huge rockets would be necessary
Although other previous proposals for Mars colonies (namely one from NASA Apollo astronaut Buzz Aldrin) advocate sending humans to Mars in craft that would loop around both the Red Planet and Earth in continuous, cycling orbits — hence their name, “Cyclers,” — Musk’s plan wouldn’t involve this type of craft, at least not initially. As Musk told Space.com:
“Probably not a Mars cycler; the thing with the cyclers is, you need a lot of them,” Musk told SPACE.com. “You have to have propellant to keep things aligned as [Mars and Earth’s] orbits aren’t [always] in the same plane. In the beginning you won’t have cyclers.”
Musk wouldn’t use any of his company SpaceX’s current proven vessels — Falcon 9 and the Dragon capsule — for the task, either, though. He admitted as much earlier in October in a Google Plus Hangout video chat (21:43).
“I would not advocate that someone travel to Mars in Dragon…it would be ridiculous, actually…it would be six months there, 18 months on the surface, and six months back. So it’d be like living in a minivan for two and a half years. Much bigger craft are needed,” Musk said at that time.
Instead, Musk envisions sending up much larger rockets and volunteer colonists in batches for the cost of about $500,000 per person. At first, 10 people would be sent to Mars, then larger groups, moving up to 80,000 per year.
The rockets, which would be larger even than SpaceX’s still-in-development Falcon Heavy (two Falcon 9 rockets combined), would also need to carry a massive amount of cargo for the journey to Mars and for getting the colony started — everything from the materials needed to build pressurized domes for growing crops, to water, which would be used not only for drinking and bathing but to shield the astronauts from harmful solar and cosmic radiation during flight.
Musk’s Mars rockets would use Methane
Musk said in his talk that when calculating the cost-per-ticket to Mars, he looked into two different major types of fuel to get there and back: hydrogen and methane.
“The cheapest fuel is methane,” Musk said. “The nice thing about methane is you can create it on Mars, because Mars has a CO2 atmosphere and there’s a lot of water ice as well.”
Musk said that initially he considered hydrogen for the fuel, but noted that “methane is much easier to deal with,” because it’s not a hyper cryogen like hydrogen — which requires extremely cold temperatures to be stored and used in liquified form.
For what it’s worth, Musk’s Mars ambitions have been public for nearly a decade: He described plans to “terraform” or alter the planet’s climate and landscape to make it more hospitable to life, to Forbes back in 2003.
Among the major remaining questions for Musk’s ambitious Mars plans are: When would the colonization effort start? Musk has previously said the “middle of the 21st century,” when the global human population has reached 8 billion. Who else would be involved — NASA? Any other spacefaring companies or governmental space agencies? What regulatory or legal hurdles would need to be cleared to allow people to travel to Mars? Who would be eligible for the trip and what would the criteria be? Who would determine these? How can Musk reasonably focus on such a herculean endeavor when he’s also running another company, Tesla Motors, and floating ideas for yet a third massive high-tech infrastructure project, a Hyperloop capable of getting travelers from Los Angeles to San Francisco in 30 minutes? Perhaps most important: How possible is it to even construct a habitable structure on Mars?
Late update: When asked by TPM for more detail about Musk’s proposed Mars colony, SpaceX spokesperson Katherine Nelson responded with the following statement:
“The long-term goal of SpaceX is to play a role in extending life beyond Earth to Mars and to make humans a multi-planetary species. SpaceX is working towards that goal by designing, manufacturing and launching the world’s most advanced rockets and spacecraft, which will ultimately make a dramatic difference in the cost and reliability of space travel.
With nearly 50 launches on our manifest for government and commercial companies alike, SpaceX is also developing technologies beyond the history-making Falcon 9 rocket and Dragon spacecraft. Under agreements with NASA, SpaceX is currently carrying out a series of 12 cargo supply missions to the International Space Station, and is modifying Dragon to carry astronauts into space in the near future. Also in development is the Falcon Heavy, the world’s most powerful rocket. And as you know, SpaceX continues to make progress towards what we believe is a key goal to transforming space exploration - developing rapidly reusable rockets. Because we are always in development mode on Grasshopper, a public schedule isn’t available, however, we will continue to test the vertical takeoff/vertical landing vehicle in successively advanced flights.”
So for now, it seems, SpaceX’s is still focused on more immediate goals — even just getting a vertical takeoff, vertical landing rocket into flying shape, and building more incrementally on the success it’s already experienced in getting Dragon into low-Earth orbit and docking it with the International Space Station. A Mars colony seems to be a much more nebulous and further-out objective.