Two people with money to burn have put down deposits for the ultimate getaway -- a trip around the moon, the president of the space tourism firm that booked the trips said this week.

Tickets to ride cost $150 million apiece which, in comparison to NASA’s multibillion-dollar Apollo moon program and the cost of flying in space in general, “is actually very affordable,” Space Adventures president Tom Shelley told the National Space Club Florida Committee during luncheon panel on space tourism.

When laughter filled the room, Shelley added, “Well, it’s good value. Let’s put it that way.”

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So far only 18 people -- all Americans, all men and all U.S. Apollo astronauts -- have orbited the moon, including the 12 who landed on the lunar surface as part of six missions that took place between July 1969 and December 1972.

The trip Space Adventures is selling features a slingshot ride around the moon and a return to Earth aboard a modified Russian Soyuz spacecraft, piloted by a professional Russian cosmonaut.

The two customers who already have booked flights may ride together on mission or be on separate excursions, the first of which could occur as early as 2017, Shelley said.

“Over the course of the next three years, we will evaluate whether those two customers will be on the first mission or if they will decide to go on the first and the second and we’ll get some other customers to go on as well,” Shelley told Discovery News.

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“We’re talking to the Russians about a series of missions, not just a one-off,” he added.

The trips could include a short stopover at the International Space Station, a research laboratory operated by 15 nations that flies about 260 miles above Earth. Space Adventures arranges for well-heeled space aficionados to fly there too.

Beginning with California businessman Dennis Tito’s trip in 2001, the company has arranged eight privately funded trips to the station, including two visits by Microsoft co-founder Charles Simonyi. British singer Sarah Brightman is due to fly next year, possibly followed by Google co-founder Sergey Brin in 2017, Shelley said.

The 10-day trips to the space station currently cost about $52 million.

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Soyuz capsules traveling to the moon will be outfitted with beefier heat shields to compensate for the faster re-entry into Earth’s atmosphere. They also will have different navigation equipment and communications systems designed to work beyond low-Earth orbit.

The biggest change, however, will be the addition of a habitation module and propulsion system that will be launched separately from the Soyuz spacecraft and attached to the capsule in Earth orbit.

“We’re basically taking the same Soyuz that flies to the space station, making a few modifications to allow it to go around to the far side of the moon and having the extra habitation module to make it more comfortable for the passengers,” Shelley said.

Including a stop at the space station, the trip to the moon will take 16- to 17 days; flying directly to the moon, about half that time. Before any people fly aboard a lunar-bound Soyuz, Russia plans an unmanned test flight, Shelley added.