A Falcon 9 rocket and Crew Dragon spacecraft carried four astronauts to the International Space Station for NASA on Wednesday morning.

It is SpaceX’s seventh human spaceflight in less than two years and NASA’s fifth mission to the International Space Station.

Crew members include Commander Kjell Lindgren, pilot Bob Hines and mission specialists Jessica Watkins and Samantha Cristoforetti.

The three U.S. astronauts and their European Space Agency (ESA) crewmate were due to arrive at the space station after a more than 16-hour flight to launch a six-month science mission about 420km above Earth. They were greeted by a team of seven, including three Russian cosmonauts.

The mission marked the fourth full-fledged ISS crew NASA has launched abroad in a SpaceX vehicle since it began flying the U.S. space agency astronauts in 2020.

SpaceX now has a fleet of four Crew Dragon vehicles: Endeavour, Resilience, Endurance and Freedom, but the company said it will not build any more Crew Dragon.

According to Benji Reeds, SpaceX’s director of human spaceflight programs, the company is likely to support only up to six human spaceflights a year.