In a conference call with reporters, Musk declined to name the people or what they had paid, though he said the individuals know each other and are "very serious" about the flight. The "private citizens" approached the company late last year and will receive training and take health and fitness tests as early as this year.
Musk said the circumlunar journey would take about a week, nearing the moon's surface without landing on it before its return to Earth. The total flight would go about 300,000 to 400,000 miles into space, he said, meaning the flight could take humans farther from Earth than ever before.
If SpaceX accomplishes the trip before NASA or another space agency can send astronauts to the moon, it would be the first lunar mission with humans in 45 years, on a course that would extend past the record 249,000 miles traveled by the Apollo 13 astronauts in 1970.
SpaceX said in a statement that the would-be passengers "have already paid a significant deposit to do a moon mission," and Musk called the cost "comparable" to that of sending astronauts to the International Space Station (ISS). NASA currently pays Russia's space agency, Roscosmos, about US$ 70m a person to fly astronauts to the ISS.
"Other flight teams have also expressed strong interest and we expect more to follow," the company statement read. "Additional information will be released about the flight teams, contingent upon their approval and confirmation of the health and fitness test results."
The flight would rely on SpaceX’s Falcon Heavy rocket, the massive engine that the company hopes to test for the first time this summer, and a Dragon 2 capsule. Musk said that the capsule had a "quite high" success rate for missions so far.
The passengers were "nobody from Hollywood," Musk said.
He acknowledged that the flight would be dangerous but said the customers have "their eyes open" about what could happen. "We're doing everything we can to minimize that risk, but it's not zero," Musk said.
"We would expect to do more than one mission of this nature," he added.
While NASA has contracted SpaceX to launch crewed missions to the ISS, the company has not yet flown any missions with humans. Musk said the space agency would receive priority if it decided to do another lunar mission first, and that the private trip would need a license from the Federal Aviation Administration. NASA's acting administrator, Robert Lightfoot, has said that the agency is reviewing a possible return to the moon or a flight into deep space beyond it.
According to The Guardian, the company will test its Crew Dragon spacecraft without humans on board later this mission and is scheduled to fly a crewed mission to the space station in 2018.