SpaceX is planning to send two people for a trip around around the moon in late 2018, Elon Musk, the company’s CEO, announced Monday.

Two passengers—private citizens, not astronauts—will launch inside a Dragon capsule atop a Falcon Heavy rocket for a weeklong, 400,000-mile loop around the moon. The space tourists paid SpaceX a “significant amount of money” for the trip and will begin training next year. Musk wouldn’t give their names or genders, nor did he say how much the journey would cost.

For the mystery passengers, the trip is a once-in-a-lifetime vacation. For Musk, the mission, if successful, could establish SpaceX as the state of the art in human spaceflight. NASA is still a few years away from testing its Space Launch System, which is supposed to carry astronauts into low-Earth orbit, and even further away from testing the system with humans on board.

If Musk meets his deadline, the moon trip will take place during the 50th anniversary of Americans’ first-ever orbit around the moon. “Like the Apollo astronauts before them, these individuals will travel into space carrying the hopes and dreams of all humankind, driven by the universal human spirit of exploration,” SpaceX said in a statement Monday.

Deadlines, of course, have not been kind to SpaceX. The company had to push several rocket tests from 2016 to this year following an explosion in September. The Falcon Heavy has never flown before, and is scheduled for a test launch this summer.

The news is bound to make the White House happy, even if it unnerves some inside NASA. President Donald Trump’s closest advisers want to return humans to the moon as soon as possible, and they’ve shown a preference for private space companies over traditional contractors with ties to the government. More and more, there’s talk of “New Space”—SpaceX, Blue Origin—gaining speed over “Old Space”—Boeing, Lockheed Martin. Musk’s announcement could earn him still more favor with Trump.