After 23.5 hours of travel, the Dragon capsule in which they were traveling splashed down off the coast of Florida at 0:43 on Friday.
“On behalf of the entire SpaceX team, welcome home”said a company official after splashdown.
The vertiginous descent was slowed down by entering the Earth’s atmosphere and then later by the deployment of huge parachutes.
The capsule will later be rescued by a ship from Elon Musk’s company. Once on board, the hatch will open for the astronauts to exit.
The crew, named Crew-3, spent the last few days aboard the ISS carrying out transfer operations with Crew-4, also made up of four astronauts (three Americans and one Italian). The new crew took off from Florida a week ago, also aboard a SpaceX ship.
Three Russian cosmonauts also remain on the ISS, arriving for their part on a Soyuz rocket.
It was the sixth landing of a manned SpaceX Dragon capsule, which regularly transports astronauts to the ISS for NASA.
Crew-3 members performed various scientific experiments. They studied, for example, how cement hardens in the absence of gravity, something that could be very useful for future construction, for example on the Moon.
They also carried out the second harvest of peppers on board the station.
During their stay, they also received the visit of a private mission, made up of three businessmen who paid SpaceX tens of millions of dollars for the trip to the ISS.