Elon Musk announced the details of one of his most ambitious projects Tuesday in Guadalajara, Mexico, during the International Astronautical Congress, telling the crowd about the challenges facing his aerospace company, SpaceX, as moves toward the goal of establishing a permanent colony on Mars.

During the presentation, Musk spoke about the necessary architecture and said governments, industry and the science community all need to collaborate to reach the goal. Specifically, he said that there needs to be a solution to refuel in orbit, create propellants on Mars and implement full reusability of resources on the planet and in the travel process.

“How do we figure out how to take you to Mars and create a self sustaining city?” Musk asked the crowd, saying that eventually humans on Earth will experience an extinction event and need to establish themselves elsewhere.

During the presentation, the entrepreneur listed the reasons why Mars was the best choice to make humans an interplanetary species. He said growing crops on the planet would be possible, adding that it would be fun to live on the planet because there is less gravity than Earth and said that it is the closest potentially habitable planet. Methane can also be harnessed there and used as the propellant to power the spaceships, he said.

He admitted it wouldn't be easy.

The endeavor will cost about $10 billion per person, he said, but he wants to cut those costs to around the median price of a house in the United States, or about $200,000 a pop. That’s a massive discount he said would come partially through reusing space ships that take people to the new planet. The ship would be reused roughly every two years, he said.

Here's how it will work, according to a visualization Musk showed. The spaceship would launch from Cape Canaveral, Florida, just like any other rocket. Once the ship exits the atmosphere, the rocket booster would detach and return right back to the launch pad where it would be prepared for another launch with a crane adding a new ship to the top while it gets refueled. The ship in orbit would also get refueled before boosting its way to Mars. Once there, the colonists would begin building a new civilization.

Musk has been notoriously tight-lipped about his company’s plan to send people to Mars. Beyond this speech, SpaceX has only announced that it plans to send a manned mission into space in 2018 on its Dragon spacecraft.