SpaceX launched four astronauts to the International Space Station on Thursday, opening a mission that will run until spring and sending up a Canadian crewmate whose wife is expecting a child while he is in orbit.

The liftoff came after a three-week delay caused by a leaking fuel system on the crew's Dragon capsule. Thick clouds threatened the countdown for much of the morning, but the skies over Cape Canaveral Space Force Station cleared enough to allow a safe launch.

Commander Jessica Watkins led the crew for NASA. Although the astronauts will spend six months aboard the space station, the trip there was the fastest yet for Elon Musk's company: a mere eight-hour transit, well under the day-long trips that many earlier Dragon missions required, with arrival well before bedtime.

With the late-morning liftoff, Watkins became the first Black woman to lead a crew to orbit. A geologist who worked with NASA's Mars rover Curiosity a decade ago, she is making her second trip to the station after a lengthy stay in 2022.

"Thanks for an amazing ride," Watkins radioed after reaching orbit.

Her three crewmates are all newcomers to space: NASA's Luke Delaney, a retired Marine; Canada's Joshua Kutryk, a colonel in the Royal Canadian Air Force; and Russia's Sergey Teteryatnikov, a former submariner. They will replace four astronauts who have been living at the orbiting laboratory since February, in a handover that keeps the station continuously staffed, as it has been since the first resident crew arrived in 2000.

This was the 13th crew SpaceX has launched for NASA, not counting the company's 2020 test flight. All four astronauts embraced their Crew-13 designation, which pays homage on their mission patch to Apollo 13, the harrowing 1970 moonshot that ended with the astronauts' safe return.

References to the number 13 abounded on launch day. Watkins and her crew rode to the pad in black Teslas bearing plates that read "Lucky 13," and they carried up a small crocheted golden dragon named Lucky, with a four-leaf clover around its neck.

"We figured it wouldn't hurt to bring a little of our own luck just in case, but clearly we don't need it," Watkins said from orbit, describing the astronauts as "four of the luckiest humans on or off planet Earth."

Kutryk is set to become the fourth man to become a father while orbiting Earth. His wife, Heather, is due to give birth to their third child in late November, and the Canadian Space Agency has promised plenty of support for the entire family when the big day comes.

"A lot of life-changing things can happen over six months," Dana Weigel, a NASA manager, said on the eve of liftoff, noting that the space agency will do its best to keep Kutryk looped in with his family.

Space agencies have handled such moments before. In 2004, NASA provided a radio link between space station astronaut Mike Fincke and his wife's delivery room during the birth of their daughter. Five years later, Randy Bresnik, commander of next year's Artemis III mission, dialed in to his wife's hospital from orbit. The happy news traveled more slowly for Austrian astronaut Franz Viehbock: his daughter was born a few hours after he launched to the Soviet Union's Mir space station in 1991, and he was not informed until the next day.

SpaceX, meanwhile, is on a roll. Three hours after Crew-13 blasted off, the company launched a Falcon rocket from California carrying more than 100 mini satellites. Another Falcon was set to soar late Thursday night from Florida with a classified satellite for the National Reconnaissance Office. The launches came in the same week that the company's massive Starship reached orbit for the first time — a stretch that captures the launch tempo the company has built across its Falcon and Starship programs.

The Associated Press' health and science coverage receives financial support from the AP Fund for Journalism and private foundations. AP is solely responsible for all content. AP's standards for working with philanthropies, a list of supporters and funded coverage areas are available at AP.org.

This story was originally featured on Fortune.com.