One day many, many years from now, Elon Musk believes the cost of taking a trip to Mars will be about the same as buying a house. During today's keynote, the SpaceX CEO said that visiting Mars should be equal to the median cost of a home in the United States, which is around $200,000. Musk said that reaching such a price through the use of "traditional methods" for space travel would be impossible. Using those established means, it would be closer to $10 billion per person, which is completely out of reach for many people who might otherwise be willing to uproot their lives and make such a daring trip.

Musk is currently giving a presentation on what it will take for humans to colonize Mars and build a city on the Red Planet. This is one man's vision, of course, so that $200,000 figure involves a big dose of guesswork. The SpaceX chief said that fitting between 100 and 200 passengers on each Mars-bound flight will bring down the trip cost for each individual traveler. And as more and more trips are completed — again, we're talking probably a century into the future here — the cost-per-ton will continue to drop. "The cost of moving to Mars ultimately could drop below $100,000," Musk said.