It’s been less than a year since Elon Musk announced his plans to settle humans on Mars during a talk in Guadalajara, Mexico. On stage at the International Astronautical Congress, the billionaire invoked the lore of Hitchhikers Guide to the Galaxy and Battlestar Galactica while describing a massive passenger ship loaded with the essentials—you know, like a movie theater and a restaurant. SpaceX hoped to launch these breezy cruises to the red planet in the early 2030s.

Plot twist: Musk's original vision is no longer canon in his universe. On Wednesday, Musk took questions during a keynote discussion at the International Space Station R&D conference in Washington, DC. In between dad jokes about tunnel digging, a staple artificial intelligence threat assessment, and a spirited attempt to unpack the potential for interplanetary war, he candidly revealed a series of obstacles for SpaceX and its plan to build a city on Mars. SpaceX is rebooting its colonization plan, and may pivot to focus on a moon base that would aid that effort.

The Hawthorne, California-based spaceflight company has spent years touting propulsive landing technology for the next version of its Dragon spacecraft. SpaceX expected to equip the Dragon V2, rated for crew and cargo, with four small SuperDraco engines and deployable landing legs to allow for a guided surface touchdown—first on the Earth’s surface, and then, maybe, on Mars. SpaceX was confident enough in the design to propose a variant of the vehicle Musk claimed would be able to land anywhere in the solar system.

The pitch for those uncrewed Red Dragon missions to Mars included a collaboration with NASA to gather landing data, test communications, and plan for potential contamination from Earth-based microbes. The space agency, of course, has its own boots-on-Mars ambitions, and hopes to send astronauts to the red planet aboard the Orion spacecraft by 2040. Musk would later compare Red Dragon launches to a “train leaving the station,” delivering cargo and science to Mars in preparation for a human mission.

But now, SpaceX has pulled the plug on its prologue to an interplanetary future.

Musk explained that Red Dragon was no longer in line with the evolving vision SpaceX has for getting to Mars—specifically, the part where you have to land on Mars. The company is hitting pause on the development of its propulsive landing technology on the Dragon V2 spacecraft. Musk argued that while the technology works, SpaceX would be put through the wringer trying to meet NASA’s safety standards for landing a human crew on the ground. “It doesn’t seem like the right way to apply resources right now,” Musk said. “I’m pretty confident that is not the right way, and that there’s a far better approach.” He later tweeted that SpaceX would still land with propulsive thrusters on Mars, but with a larger spacecraft.

SpaceX has had a busy year adding to its growing arsenal of recovered rockets while launching more times than any other year since its founding. The company also managed to re-fly both its Falcon 9 rocket and Dragon cargo capsule. In the flurry of praise surrounding rocket landings and Mars concepts, the fact that SpaceX has yet to attempt or complete a deep space mission of any kind still weighs on the company’s future. Red Dragon would have been SpaceX’s first toe into the deep end of the pool.

Its journey would have begun atop the triple-booster Falcon Heavy rocket, the famously-delayed launch vehicle that Musk claims has over twice the payload capability of a single Falcon 9 rocket, able to easily deliver 100,000 pounds to low-Earth orbit. At the ISS R&D conference, Musk invited the audience and those watching the livestream to witness the launch of the vehicle—currently projected for this fall—from Kennedy Space Center. But he followed with an uneasy disclaimer: “Real good chance that vehicle doesn’t make it to orbit.”