NASA is hoping those crew-ferrying flights begin by late 2018.

SpaceX's own Falcon Heavy rocket, which Musk wants to use for the lunar tourist mission, is scheduled to make a debut test flight later this year.

Musk, also CEO of electric carmaker Tesla, said missions around the moon could provide practice for eventual human flights to Mars, the long-term goal of SpaceX.

Except for needed communications upgrades, the Dragon spaceship in development for NASA astronauts is well suited for lunar flyby missions, Musk added.

The launch would require licensing by the Federal Aviation Administration.

SpaceX joins a growing list of companies developing commercial passenger spaceflight services.

Virgin Galactic, an off shoot of Richard Branson's London-based Virgin Group, is testing a six-passenger, two-pilot spaceship to carry paying customers about 62 miles (100 km)above Earth, high enough to experience brief microgravity andsee Earth's curvature against the blackness of space.

Tickets to ride cost $250,000 each.

SpaceX has a $70 billion backlog of about 70 missions for NASA and commercial customers. The firm's backers include Alphabet's Google Inc and Fidelity Investments, which together have contributed $1 billion to Musk's firm.

Reuters