If you have a strong hankering to get so close to the Moon that you can gaze into the bottoms of craters, have many millions of dollars that you don't need, and are willing to undergo vigorous training, SpaceX may have the trip of a lifetime for you in the relatively near future. SpaceX (and Tesla) CEO Elon Musk announced earlier today that the company planned to take two tourists on a trip past the Moon, into deep space, and back again, sometime in late 2018. The trip would cover a total of 300,000 to 400,000 miles, and it would end with a parachute landing. Musk did not name the two tourists, but said that they knew each other, were "nobody from Hollywood," and that they would get extensive training before going into space. He also said the company had already received a "substantial" deposit from the tourists.

A lot of details are still lacking, but here's some of what we know so far:

1. How much will it cost?

SpaceX isn't saying. But Musk suggested that in time, the company would fly tourists to space once or twice a year and that the fares for these flights might eventually make up 10 to 20 percent of the company's revenues. Although SpaceX is a private company, The Wall Street Journal got its hands on company records which suggest its revenues may be as high as $1 billion a year. If so, that suggests a moon fly-by might cost $100 million or so. Musk has also said the cost would be comparable or a little higher than the cost of a crewed mission to the International Space Station on a Russian Soyuz rocket. Russia charges NASA between $21 million and $82 million per round trip.

2. Will the tourists really fly in 2018?

If you're a fan of Elon Musk, you know he likes to set himself difficult deadlines that he often fails to meet. In this case, SpaceX is planning to send the tourists to space in a Dragon 2 spacecraft currently under development, with its first uncrewed test flight planned for this summer, and its first flight to the International Space Station planned for late this year. We all know that space flights don't always go as expected, so it's anyone's guess whether this trip will happen on schedule or be delayed.

3. Will these two be the first space tourists?

No. The Russians have been taking tourists on their Soyuz rockets since 2001.

4. Wasn't Richard Branson supposed to be doing this?

Yup, he was. His company Virgin Galactic reportedly collected some $80 million in deposits from tourists wanting to get to space, something he originally promised would happen in early 2010. It hasn't, and multiple attempts to build and fuel rockets that would do the job have hit a variety of snags. The most recent and spectacular of these was the destruction of the company's VSS Enterprise, which broke apart in midair over the Mojave Desert, killing its co-pilot and seriously injuring its pilot.

Even before that crash, newspapers were reporting growing impatience from some who had paid deposits for Virgin Galactic trips. On the other hand, a couple of months ago, Virgin Galactic had a successful glide test of its passenger spacecraft. So don't count the company out just yet.

5. What about Mars?

Musk has announced his plan to get humans to Mars, although true to form, the target date for that trip is a moving target. He at one point said his best case scenario for Mars was 2021; he now says it might happen in 2024.

This trip past the Moon, whenever it occurs, will be a step in that direction. "Designed from the beginning to carry humans, the Dragon spacecraft already has a long flight heritage," according to the SpaceX announcement about the trip. "These missions will build upon that heritage, extending it to deep space mission operations, an important milestone as we work towards our ultimate goal of transporting humans to Mars."

With that in mind, instead of blowing your savings on a Moon fly-by, you might want to save up for a really big trip.