Last week, SpaceX made one of their biggest announcements yet — which is saying something, because SpaceX makes a lot of big, exciting announcements: They’re planning to send people on a trip around the Moon before the end of next year!

The two-person crew will spend about a week in space: they’ll head to the Moon, loop around it once, then come back home. Which, first of all, sounds amazing.

No humans have left Earth orbit since the Apollo program ended more than forty years ago. And now we’re going back! But getting humans back to the Moon will take a lot of work.

SpaceX has never sent people to space before at all — just supplies and satellites. Plus, the key components they’ll need for this mission have spent the last few years hitting snags and delays. And despite that, they’re saying they want to send people all the way to the Moon in less than two years.

So it’s a pretty ambitious goal, and a lot of things will have to come together very quickly if they’re going to be able to pull it off. SpaceX has spent the last few years improving their Falcon 9 rocket, which is what they use to launch satellites into orbit and supplies to the International Space Station, or ISS. They’ve also been improving the Dragon capsule, which sits on top of the rocket and carries the cargo to the ISS.

But the Falcon 9 can only launch things as far as Earth’s orbit, and the version of Dragon they’re using now isn’t designed to carry humans. So SpaceX has been working on a new rocket -- the Falcon Heavy -- and a new capsule called the Crew Dragon to go with it. The Falcon Heavy is basically three Falcon 9s strapped together, which will make it the largest active rocket in the world once it’s finally on the pad.

The Crew Dragon will carry a human crew and everything they need in space. It’ll also come with safety features like a launch abort system that automatically shoots the capsule away from the rocket if something goes wrong. Together, the Falcon Heavy and the Crew Dragon will be able to get people to the Moon and back.

But the rocket and capsule are both still in development. Crew Dragon’s gone through some early testing, but its first test flight to the ISS isn’t until November of this year. And that’s an uncrewed test.

Then, the first crewed test flight, with two NASA astronauts onboard, is set for May 2018. The Falcon Heavy, meanwhile, has its first launch scheduled for this summer — and that’s just a demo to show what it can do. After that, it’s scheduled to bring a few satellites into orbit this fall -- assuming that nothing goes wrong during the first launch.

And then … it’s off to the Moon? That doesn’t seem like a whole lot of time for testing before sending people on a trip that’ll take them hundreds of thousands of kilometers from Earth. And, to be clear, these are private citizens who are paying a ton of money for this trip.

SpaceX hasn’t released their names or how much they’re paying, although it’s probably safe to assume that it’s a lot more than $58 million or so that it’ll eventually cost to send astronauts to the ISS on the Crew Dragon. So the crew won’t be professional astronauts with expert training for this mission. They’ll still get some fitness testing and emergency training before they go up, just in case something goes wrong, but it won’t be as rigorous or as drawn-out as full astronaut training is.

But they also might not need more training, since they won’t actually be flying the ship. The flight will be almost completely automatic, with any course corrections either pre-programmed before launch or directed from SpaceX headquarters down on the ground. But there’s a chance that they’ll have more prep time than SpaceX is planning for, anyway.

Delays are pretty common in the rocket-launching business. The Falcon Heavy was originally supposed to be done in 2013, but it still hasn’t launched. Most recently, practically everything SpaceX was working on got delayed while they figured out what went wrong in last year’s Falcon 9 explosion.

That included the first Crew Dragon tests, which also pushed back all the other Crew Dragon tests and missions like the ones to the ISS. This stuff is literally rocket science, and SpaceX has to make sure they get it exactly right — especially when there are lives at stake. But whether it happens next year or in 2020 or in 2025, SpaceX will probably send people to the Moon eventually.

And with their long-term plans to send humans to Mars, it might not be long before people are buying tickets there, too. And I don’t know about you, but that’s a future I’m excited for. Speaking of launches: our brand-new channel, SciShow Psych, just launched earlier this week!

The first two episodes are already up, so head on over to youtube.com/scishowpsych if you want to check it out. And don’t forget to subscribe!