CAPE CANAVERAL, Fla. >> Four astronauts from four countries rocketed toward the International Space Station today.

They should reach the orbiting lab in their SpaceX capsule on Sunday, replacing four astronauts living up there since March.

A NASA astronaut was joined on the predawn liftoff from Kennedy Space Center by fliers from Denmark, Japan and Russia. They clasped one another’s gloved hands upon reaching orbit.

It was the first U.S. launch where every spacecraft seat was occupied by a different country — until now, NASA had always included two or three of its own on its SpaceX taxi flights. A fluke in timing led to the assignments, officials said.

“We’re a united team with a common mission,” NASA’s Jasmin Moghbeli radioed from orbit. Added NASA’s Ken Bowersox, space operations mission chief: “Boy, what a beautiful launch … and with four international crew members, really an exciting thing to see.”

Moghbeli, a Marine pilot serving as commander, is joined on the six-month mission by the European Space Agency’s Andreas Mogensen, Japan’s Satoshi Furukawa and Russia’s Konstantin Borisov.

“To explore space, we need to do it together,” the European Space Agency’s director general, Josef Aschbacher, said minutes before liftoff. “Space is really global, and international cooperation is key.”

The astronauts’ paths to space couldn’t be more different.

Moghbeli’s parents fled Iran during the 1979 revolution. Born in Germany and raised on New York’s Long Island, she joined the Marines and flew attack helicopters in Afghanistan. The first-time space traveler hopes to show Iranian girls that they, too, can aim high. “Belief in yourself is something really powerful,” she said before the flight.

Mogensen worked on oil rigs off the West African coast after getting an engineering degree. He told people puzzled by his job choice that “in the future we would need drillers in space” like Bruce Willis’ character in the killer asteroid film “Armageddon.” He’s convinced the rig experience led to his selection as Denmark’s first astronaut.

Furukawa spent a decade as a surgeon before making Japan’s astronaut cut. Like Mogensen, he’s visited the station before.

Borisov, a space rookie, turned to engineering after studying business. He runs a freediving school in Moscow and judges the sport, in which divers shun oxygen tanks and hold their breath underwater.

One of the perks of an international crew, they noted, is the food. Among the delicacies soaring: Persian herbed stew, Danish chocolate and Japanese mackerel.

SpaceX’s first-stage booster returned to Cape Canaveral several minutes after liftoff, an extra treat for the thousands of spectators gathered in the early-morning darkness.

Liftoff was delayed a day for additional data reviews of valves in the capsule’s life-support system. The countdown almost was halted again today after a tiny fuel leak cropped up in the capsule’s thruster system. SpaceX engineers managed to verify the leak would pose no threat with barely two minutes remaining on the clock, said Benji Reed, the company’s senior director for human spaceflight.

Another NASA astronaut will launch to the station from Kazakhstan in mid-September under a barter agreement, along with two Russians.

SpaceX has now launched eight crews for NASA. Boeing was hired at the same time nearly a decade ago, but has yet to fly astronauts. Its crew capsule is grounded until 2024 by parachute and other issues.