During his hour-long announcement of the SpaceX Mars colonization plan, CEO Elon Musk didn’t say where exactly Martian colonists will live once they arrive on the planet — and how exactly they’ll survive given the harsh environment.

Musk seemed particularly unconcerned about solar radiation. “The radiation thing is often brought up, but it’s not too big of a deal,” he says. There is a “slightly increased risk” of cancer, he says, and there will probably be some sort of shielding. He talked of creating an artificial magnetic field on Mars to deflect high-energy particles, especially to protect colonists from solar flares. But Musk didn’t provide any information of how this magnetic field would be created.

Watch: SpaceX Mars safety and habitat Q&A

Musk says SpaceX’s goal is to build the transport system, like building the Union Pacific Railroad. “Once that transport system is built,” Musk says, “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.” People will be able to go to the planet and build “anything from iron refineries to the first pizza joint.”

In a video SpaceX released to detail its “Interplanetary Transport System,” the colonists are seen arriving on Mars and finding no habitat on its surface.

Here are some questions about the Mars habitats that we still think should be addressed: what will the habitats look like? Will they be underground? Is there assembly required? What about life support? Water? Air? Food? Will resources come from Earth or will the colonists live off the land? How will the colonists deal with the effects of reduced gravity?

Colonists will need a life-support system to create breathable air, a way to recycle water, and a way to feed themselves. No one has ever tried doing any of these things on Mars and the challenges are of course enormous.

SpaceX CEO Elon Musk has unveiled the design for the giant rocket booster he wants to build in order to colonize Mars. It is part of what SpaceX is referring to as the “Mars Vehicle” — the rocket booster and the Mars spaceship combined — and Musk announced it on stage in Guadalajara, Mexico at the 67th International Astronautical Conference.

SpaceX teased the rocket in a promo video released shortly before Musk’s talk. The massive, single-core rocket will be responsible for launching a huge spaceship filled with 100 metric tons of passengers and cargo from Earth. To do this, it is capable of generating 28,730,000 pounds of thrust at liftoff, resulting in a top speed of about 5,375 miles per hour. It will use 42 of SpaceX’s new Raptor engines, the first of which was tested earlier this week.

On stage, Musk shared that the 77.5-meter-tall rocket will be made of an advanced carbon-fiber material. The rocket’s engines will be powered by methane (or “deep cryo-methalox”) fuel — SpaceX currently uses kerosene to power the Falcon 9 rocket. The rocket will also be self-pressurized, ditching the need for the sometimes troublesome helium pressurization system that is used by the Falcon 9.

We also learned that SpaceX plans to make this rocket almost instantly reusable, similar to the plan for SpaceX’s current rocket, the Falcon 9. Musk said on stage that he plans to make the rocket capable of landing 20 minutes after launch, and that he wants to reuse each rocket booster up to 1,000 times. After the rocket takes off and delivers the company’s spaceship to a parking orbit above the Earth, it is supposed to land back at Cape Canaveral to be fitted with a fueling tank. It will then fly back to space to fuel the spaceship for its trip to Mars. The rocket would then land a second time.

By making the rocket reusable instead of discarding it after every launch, Musk said SpaceX hopes to some day make the cost of going to Mars about the same as buying a house. For cargo, he said he hopes to get the cost down to about $140,000 per ton.

Musk has been teasing details about this rocket for years, but up until now, the specifics of the vehicle have been mostly a mystery. Musk said that the simulation video shown off today is “quite close to what we will actually build,” and clarified that it’s “not an artist’s impression.” The simulation was made from SpaceX’s CAD (an engineering program) models, he said. Musk also held to his previously-stated, but admittedly loose, goal of sending humans to Mars in the mid-to-late 2020s.

Prior to today’s announcement, the secret rocket had been codenamed the BFR — for Big Fucking Rocket — a reference to a giant gun called the BFG in the video game Doom. And given the rocket’s size, it’s easy to see how it got that nickname.

Developing… Check out our SpaceX Mars Colonization liveblog for the latest updates and our storystream for all the news!

SpaceX trip to Mars simulation