Elon Musk is ready for humans to colonize Mars, and he claims it's not only possible, but affordable.
Musk recently published his paper on "Making Humans a Multi-Planetary Species."
In it, he argues: "One path is we stay on Earth forever, and then there will be some eventual extinction event. I do not have an immediate doomsday prophesy, but eventually, history suggests, there will be some doomsday event."
But despite the urgency, Musk says our current methods would mean $10 billion per person for a trip to Mars — too expensive for colonization. He wants to get the ticket price down to about $200,000.
So, does Musk plan to drive costs down? And specifically, down by 5 million percent?
According to his plans, making spaceships reusable and refillable in orbit might significantly cut the cost. SpaceX and Jeff Bezos' space company Blue Origin have both been testing rockets like that for the past couple years.
SpaceX has already produced an engine worthy of the Mars mission. The first photos of the "Raptor interplanetary transport engine" were published in September 2016.
Musk isn't alone in his aspirations to go to Mars.
NASA hopes to send people to Mars by 2033, and the president has supported doing that. Back in March, Donald Trump signed over almost $20 billion for NASA funding — $4 billion of that could go toward a Mars mission.