The first private launch vehicle, private crew mission to the International Space Station is officially en route. At 11:17 a.m. Eastern Standard Time, a Falcon 9 rocket chartered by Axiom Space carried four very rich people in a Crew Dragon up for an eight-day stay on the ISS.

The mission is a milestone in commercial space circles. Though there’s been government investment in the development of Crew Dragon and the Falcon 9, the four passengers — former astronaut and Axiom vice president Michael López-Alegría, real estate developer Larry Connor, investor Mark Pathy, and former pilot-turned-defense-businessman Eytan Stibbe — all paid their way or were paid privately to go to the space station in a deal between Axiom Space and SpaceX, with cooperation from NASA and other entities.

But NASA took a pretty hands-off approach to the mission, leaving Axiom and SpaceX more in command. The crew will spend the next day awaiting rendezvous with the ISS, at which point their eight-day stay will begin.

The crew will be spending their time doing the same things that NASA, ESA, and Roscosmos spacefarers do: running various experiments having to do with human health in the microgravity environment, including ways it affects the heart and brain.

Axiom-1: Are they the first private astronauts to the ISS?

Although the mission is privately funded — both the vehicle and the crew are outside the NASA ecosystem — the four will not be the first tourists on the ISS. Billionaire Dennis Tito paid Roscosmos $20 million for a ride aboard a Soyuz, staying for around the same amount of time Axiom-1 will. All subsequent ISS tourists have flown from Russian soil, marking another historic first for Axiom-1.

In total, seven private passengers have made their way to the space station via Space Adventures. One of them, video game developer Richard Garriott, managed to make a truly dreadful short film up there called Apogee of Fear, embedded below. No Axiom-1 personnel are currently expected to produce a film aboard the ISS, but you never know.

What is Axiom Space?

Axiom Space is a Houston-based private space company that contracts with SpaceX for space tourism flights but has bigger ambitions of its own: building a private space station. The first step is an under-development module for the ISS outfitted specifically with private tourists in mind.

That module will be able to detach from the ISS when it is decommissioned, forming the basis for an all-private space station. Axiom was not among the companies selected by NASA to further develop private-public partnership space stations, but that doesn’t rule out public-sector astronauts of various countries from going to the eventual Axiom space station.

Will there be an Axiom-2?

Axiom-2 is expected to fly at the earliest in fall 2022, though that may not happen until this time next year. Only half the crew of that mission has been selected. Peggy Whitson, a highly decorated NASA astronaut with a NASA record-breaking total stay in space, will serve as mission commander, while GT race car driver and businessman John Shoffner will serve as pilot.

Axiom has at least two other missions planned: Axiom-3 and Axiom-4, both currently slated for launches next year.