The US space agency's international Crew-12 lifted off at approximately 5:15 am local time (1015 GMT) aboard a SpaceX Falcon 9 rocket from the Cape Canaveral launch site in Florida, according to a NASA video feed.
The astronauts will replace a crew that returned from the station early due to a medical issue with one of its members.
The pre-dawn launch was delayed by two days over adverse weather forecasts across the US East Coast, including high winds that could have complicated any potential emergency maneuvers.
The astronauts are expected to arrive at the ISS by approximately 3:15 pm local time on Saturday.
Crew-12 is composed of Americans Jessica Meir and Jack Hathaway, along with French astronaut Sophie Adenot and Russian cosmonaut Andrey Fedyaev.
"We have left the Earth, but the Earth has not left us," Meir said as the astronauts ventured into space. "When we gaze on our planet from above, it is immediately clear that everything is interconnected."
"We are one humankind." The travelers are replacing Crew-11, which returned to Earth in January a month earlier than planned in the first medical evacuation in the space station's history.
The ISS, a scientific laboratory orbiting 250 miles (400 kilometers) above Earth, has since been staffed by a skeleton crew of three.
NASA declined to disclose any details about the health issue that cut the previous mission short.
Once the astronauts arrive, they will be one of the last crews to live aboard the football field-sized space station.
Continuously inhabited for the last quarter-century, the aging ISS is scheduled to be pushed into Earth's orbit before crashing into an isolated spot in the Pacific Ocean in 2030.
The ISS, once a symbol of warming post-Cold War relations, has been a rare area of continued cooperation between the West and Russia since Moscow invaded Ukraine in 2022.
However, the space station has not entirely avoided the tensions back on Earth.
In November, Russian cosmonaut Oleg Artemyev -- who had long been planned to be a member of Crew-12 -- was suddenly taken off the mission.
Reports from independent media in Russia suggested he had been photographing and sending classified information with his phone. Russian space agency Roscosmos merely said he had been transferred to a different job.
His replacement, Fedyaev, has already spent some time on the ISS as part of Crew-6 in 2023.
During their eight months on the outpost, the four astronauts will conduct many experiments, including research into the effects of microgravity on their bodies.
Meir, who previously worked as a marine biologist studying animals in extreme environments, will serve as the crew's commander.
Adenot has become the second French woman to fly to space, following in the footsteps of Claudie Haignere, who spent time on the Mir space station.
When Adenot saw Haignere's mission blast off, she was 14 years old -- a moment she has called "a revelation." Among other research, the European Space Agency astronaut will test a system that uses artificial intelligence and augmented reality to allow astronauts to carry out their own medical ultrasounds.
Related Links
SpaceX
Space Tourism, Space Transport and Space Exploration News
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
