SpaceX will send two millionaires on a week-long private spaceflight around the moon and back to Earth (a voyage similar to that of Apollo 8 in December 1968), probably by the fourth quarter of 2018 or early 2019.

SpaceX founder and chief executive Elon Musk revealed these two "private individuals," likely millionaires or billionaires that can afford the seven- or eight-figure price tag, approached him with this idea of making a circumlunar trip around the Moon.

Like Us on Facebook

"They're very serious about it," said Musk, who refused to identify the passengers.

The two private citizens have "already paid a significant deposit" for the cost of the mission, according to Musk. The SpaceX boss did, however, reveal the clients include "nobody from Hollywood."

Musk said SpaceX will use its Falcon Heavy rocket to send the two paying passengers into space aboard one of the company's Dragon 2 spacecraft or Crew Dragon. The names of the two individuals will be announced later, after the result of initial health tests to ensure their fitness for the mission, said SpaceX in a statement.

The Dragon spacecraft carrying these two space tourists will fly on autopilot; loop around the far side of the Moon on a "free-return" trajectory, then head back to Earth.

"This would do a long leap around the moon," said Musk.

"We're working out the exact parameters, but this would be approximately a week-long mission, and it would skim the surface of the moon, go quite a bit farther out into deep space, and then loop back to Earth. I'm guessing probably distance-wise, maybe 300,000 or 400,000 miles."

He said the voyage will be risky.

"I think they are entering into this with their eyes open, knowing that there is some risk here," said Musk of the passengers. "They're certainly not naive. We'll do everything we can to minimize that risk, but it's not zero."

"They do know each other," said Musk of his space tourists.

"I don't want to comment too much on their background, but they certainly will have extensive training before going on the mission, and I also can't say the exact amount (they will pay)."

TagsSpaceX, millionaires, moon, Apollo 8, Elon Musk, Dragon 2 spacecraft, Crew Dragon, Falcon Heavy rocke