Elon Musk’s SpaceX announced plans today to send two unnamed private citizens around the moon “late next year.” The two passengers “have already paid a significant deposit to do a moon mission,” a SpaceX press release reads.

If SpaceX manages to rocket the two wealthy citizens around (note: not on) the moon in 2018, it will mark a significant step forward for space tourism and financing the future of interplanetary travel. SpaceX says private missions like this one also reduce the cost of government-funded missions over time.

Musk says the mission will likely use SpaceX’s Dragon 2 spacecraft and the Falcon Heavy rocket.

More, from SpaceX:

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. We expect to conduct health and fitness tests, as well as begin initial training later this year.

SpaceX says this mission won’t be its last: “Other flight teams have also expressed strong interest and we expect more to follow. Additional information will be released about the flight teams, contingent upon their approval and confirmation of the health and fitness test results.”

If you’re interested in signing up for Musk’s next trip, now may be a good time to hit the gym — becoming a billionaire wouldn’t hurt, either.