On Tuesday in Guadalajara, Mexico, at the 67th International Aeronautical Congress, SpaceX chief Elon Musk unveiled his plans for colonizing Mars.

“If we can get the cost of moving to Mars to be roughly equivalent to a median house price in the U.S., which is around $200,000, then I think the probability of establishing a self-sustaining civilization is very high. I think it would almost certainly occur.”

Mars has been the destination from day one for SpaceX, which went from a rocket engine in a garage to supplying the International Space Station over the last 14 years. But, aside from an announced Mars-landing version of the Dragon capsule that it uses to send supplies to the space station, details of Musk’s dream have been rather vague. Until now.

Speaking to a packed auditorium of space fans, engineers, and reporters from around the world, some of whom waited for hours to see him speak, Musk started by addressing the obvious question of why Mars (for the spirit of adventure and to back up Earth’s biosphere) and why now (because the technology exists to do it in our lifetime).

He then laid out plans for SpaceX to develop four major components to comprise an interplanetary transportation system. These are:

  • A booster rocket, for launching the other components;
  • A spaceship for transporting colonists from Earth to Mars;
  • A tanker ship, for fueling the spaceship in Earth orbit; and
  • A propellant plant, for producing methane and oxygen propellants on the surface of Mars for return journeys of the spaceship (not necessarily passengers, though some might elect to return to Earth rather than settling on Mars).

Musk also showed off significant progress in building major elements of the system.

First up, the company needs a new rocket engine to power the transportation system. This is the Raptor. Only about the same size of the company’s existing Merlin engine, which powers its Falcon 9 orbital rockets, the Raptor is nevertheless three times more powerful than the Merlin, Musk said, thanks to higher propellant pressure.

Musk said the team developing the engine worked overtime to complete a test firing in time for Musk to show it off during his talk.

“The Raptor is a really tricky engine,” said Musk. “It’s a lot trickier than Merlin because it’s a full-flow staged combustion, much higher pressure. I’m kind of amazed it didn’t blow up on the first firing, but fortunately it was good.”

The photo that Musk presented is particularly spectacular given that it was a horizontal test firing at night, with the shock diamonds of the supersonic exhaust plume clearly visible.


Next up in development, and a piece that Musk said is perhaps even trickier than the engine, is the carbon fiber structure of the of the booster rocket.

Here too, Musk had a team working overtime to complete a prototype propellant tank, the walls of which will also form the structure of the booster rocket itself. The challenge here is to take advantage of the strength and low weight of carbon fiber while also containing supercooled propellants as well as today’s metal structures.

The booster will be powered by 42 Raptor engines. Fourteen of those engines clustered in the center of the rocket’s base will steer the stacked booster and spaceship by means of a gimbal that will direct their thrust.

Riding atop the booster will be the 100-person spaceship. The ship will launch from pad 39A at Cape Canaveral, Florida, the same pad that launched the Apollo astronauts to the moon. Once in orbit, the ship will transfer the colonists to an identical ship already in orbit. That ship, having been there for some weeks, will have been fueled for the 90-day journey to Mars by repeated launchings of a tanker ship that will essentially be a flying gas tank version of the spaceship.

Once fueled, the spaceship will depart Earth orbit for the long journey to Mars. Musk says the ride inside the spacious interior of the spaceship will be fun and not boring.

“In order to make it appealing and increase that portion of the ven diagram of people who actually want to go, it’s gotta be really fun and exciting and it can’t feel cramped or boring. So the crew compartment is such that you can do zero g games, you can float around. There’ll be movies, lecture halls, cabins, a restaurant. It’ll be really fun to go. You’re going to have a great time.”

The first ship will be called Heart of Gold, said Musk, after the sleek spaceship in Douglas Adams’ The Hitchhiker’s Guide to the Galaxy, which was powered by an infinite improbability drive. That’s appropriate to this endeavor, said Musk, because his whole venture is also rather improbable.

But even given the extreme difficulty and a high risk of failure, the effort is worth making, because a serious effort can, in fact, now be made.

Hat tip to Jeff Foust, who asked the question following Musk’s talk that got him to quantify just how much effort he and SpaceX are making, in dollar terms.

Musk said his company is currently spending “well under 5% of the company” on the Mars transporter project.

Maybe we’re spending a few tens of millions of dollars on it right now. So it’s relatively small. But then as we finish development of the final version of Falcon 9—which should be some time next year, and Dragon 2—and get the reusability of the boost stage and reusability of Dragon 2 sorted out, we’ll gradually apply more and more resources to the interplanetary system…. Perhaps within a year and a half to two years we should have most of SpaceX engineering working on the interplanetary system, and hopefully be able to spend maybe more on the order of a couple hundred million dollars a year, maybe $300 million a year on the system.

Overall, says Musk, the system will require around $10 billion to get up and running. Eventually, he envisions a fleet of a thousand or so ships plying the spaceways between Earth and Mars, ferrying the people and supplies needed to build a self-sustaining colony of a million people on Mars over a period of 40 to 100 years.

As for exactly how the colony will be established, what kinds of habitats will be built, along with all the other infrastructure of a thriving colony, that’s going to be up to other entrepreneurs and visionaries to figure out.

The goal of SpaceX is really to build the transport system. It’s like building the Union Pacific Railroad. Once that transport system is built, then there’s a tremendous opportunity for anyone who wants to go to Mars and create something new or build the foundations of a new planet.

Things like iron refineries and the first pizza joint, said Musk.