In a talk on Tuesday at the International Astronautical Congress in Guadalajara, Mexico, SpaceX CEO Elon Musk laid out engineering details to establish a permanent, self-sustaining civilization of a million people on Mars, with an initial flight as soon as 2024.

SpaceX is designing a massive reusable Interplanetary Transport System spacecraft with cabins. The trip would initially cost $500,000 per person, with a long-term goal of 100 passengers per trip.

Musk plans to make humanity a “multiplanetary species” to ensure survival in case of a calamity like an asteroid strike. “This is really about minimizing existential risk and having a tremendous sense of adventure,” he said.

The new rocket could also be used for other interplanetary trips to places like Europa, the icy moon of Jupiter.

SpaceX | SpaceX Interplanetary Transport System

Space X | Making Humans a Multiplanetary Species