A recycled SpaceX Crew Dragon capsule with four astronauts aboard on Saturday docked at the International Space Station (ISS) after a flight of over 23 hours.

The Dragon capsule docked autonomously with the orbiting outpost more than 260 miles (420 kilometers) above the Indian Ocean.

NASA and SpaceX launched the astronauts early on Friday in the third crewed mission of the U.S. commercial rocket company in less than a year.

The four are U.S. astronauts Shane Kimbrough and Megan McArthur, France's Thomas Pesquet, and Japan's Akihiko Hoshide.

They will conduct science and maintenance during a six-month stay aboard the orbiting laboratory and will return no earlier than October 31, according to NASA.

They will also replace four astronauts who will return to Earth in their own Dragon capsule Wednesday.

It was the first time two SpaceX crew Dragons were parked there at the same time – practically side by side. "We are so excited to have you aboard," radioed the space station's commander, Shannon Walker.

Although this was SpaceX's third crew flight for NASA, it was the first to use a vehicle that's flown before, an essential part of Musk's push to the moon and Mars. The Dragon capsule was used for SpaceX's first crew launch last May, while the Falcon rocket soaring Friday hoisted Crew-2 in November.

NASA astronauts Kimbrough and McArthur – the commander and pilot of the returning Dragon – monitored their capsule's flat-screen computers as the space station loomed ever larger. They could have taken control if necessary, but the autonomous system did its job, much like a self-driving car.

Pesquet and Hoshide have lived in the ISS before, as has Kimbrough. It was the first station visit for McArthur.

McArthur flew to the space station in the same seat and the same capsule – named Endeavour – as her husband, Bob Behnken, did on SpaceX's debut crew mission.

For the next four days, the space station will be home to 11 astronauts, just shy of the record of 13 set during NASA's space shuttle era. The current population includes six Americans, two Russians, two Japanese and one French. It will shrink by four on Wednesday when three Americans and one Japanese depart for home and a splashdown in the Gulf of Mexico.

(With input from AP)