It has been over four decades since the United States has sent astronauts to the moon. But next year, a private company is taking two private citizens around the moon, and this will mark the farthest humans have ever travelled in outer space.

Earlier this week, SpaceX CEO Elon Musk announced on the company’s website that they have been approached to fly two private citizens on a trip around the moon, and the moon mission will take place in late 2018. It was said that the two unnamed tourists “have already paid a significant deposit” for the trip. The tourists will be aboard the company’s Crew Dragon capsule, which will have an unmanned test flight later this year.

SpaceX will be conducting health and fitness tests, as well as begin initial training later this year. Musk said that other flight teams have also expressed interest in the moon mission and are expecting more to follow. More information will be released regarding the flight teams after the approval and confirmation of the health and fitness test results.

Following the announcement, NASA also issued a statement about the private space mission around the moon, saying that the space agency “commends its industry partners for reaching higher.”

“We will work closely with SpaceX to ensure it safely meets the contractual obligations to return the launch of astronauts to U.S. soil and continue to successfully deliver supplies to the International Space Station,” said NASA.

It has speculated that the two unnamed tourists are most likely part of Hollywood’s elite. However, Musk said that the mysterious duo is “nobody from Hollywood,” according to The Mercury News. The CEO only revealed that the two people do know each other and that they came to SpaceX with the proposal that they be rocketed in the direction of the moon.

Musk said that he did not have permission to identify them or to say if they were men or women or even pilots.

“I think they are entering this with their eyes open, knowing that there is some risk here,” Musk told reporters in a telephone conference. “They’re certainly not naïve, and we’ll do everything we can to minimize that risk, but it’s not zero. But they’re coming into this with their eyes open.”

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