CAPE CANAVERAL, Fla. (AP) — Four astronauts embarked on a high-stakes flight around the moon Wednesday, humanity’s first lunar voyage in more than half a century and the thrilling leadoff in NASA’s push toward a landing in two years.

Carrying three Americans and one Canadian, the 32-story rocket rose from NASA’s Kennedy Space Center where tens of thousands gathered to witness the dawn of this new era. Crowds also jammed the surrounding roads and beaches, reminiscent of the Apollo moonshots in the 1960s and ’70s. It is NASA’s biggest step yet toward establishing a permanent lunar presence.

Artemis II set sail from the same Florida launch site that sent Apollo’s explorers to the moon so long ago. The handful still alive cheered this next generation’s grand adventure as the Space Launch System rocket thundered into the early evening sky, a nearly full moon beckoning some 248,000 miles away.

Artemis II commander Reid Wiseman led the charge into space with “Let’s go to the moon!” accompanied by pilot Victor Glover, Christina Koch and Canada’s Jeremy Hansen. It was the most diverse lunar crew ever with the first woman, person of color and non-U.S. citizen riding in NASA’s new Orion capsule.

They shaped their hands into hearts as they said goodbye to their families and boarded the astrovan for the ride to the pad and their awaiting space chariot. “Love you guys,” Glover said.

The astronauts will stick close to home for the first 25 hours of their 10-day test flight, checking out the capsule in orbit around Earth before firing the main engine that will propel them to the moon.

They won’t pause for a stopover or orbit the moon like Apollo 8’s first lunar visitors did so famously on Christmas Eve 1968, reading from Genesis. But they stand to become the most distant humans ever when their capsule zooms past the moon and continues another 4,000 miles beyond, before making a U-turn and tearing straight home to a splashdown in the Pacific.

Once settled in a high orbit around Earth, the astronauts planned to assume manual control and practice steering their capsule around the rocket’s detached upper stage, venturing within 33 feet. NASA wants to know how Orion handles in case the self-flying feature fails and the pilots need to take control.

Four days later during the lunar flyby, the moon will appear to be the size of a basketball held at arm’s length. The astronauts will take turns peering through Orion’s windows with cameras. If the lighting is right, they should see features never before viewed through human eyes. They’ll also catch snippets of a total solar eclipse, donning eclipse glasses as the moon briefly blocks the sun from their perspective and the corona is revealed.

All of NASA’s moon plans — a surge in launches over the next several years leading to a sustainable moon base for astronauts assisted by robotic rovers and drones — hinge on Artemis II going well.

It’s been more than three years since Artemis I, the only other time NASA’s SLS rocket and Orion capsule have soared. With no one aboard, the Artemis I capsule lacked life-support equipment and other crew essentials like a water dispenser and toilet.

These systems are now making their space debut on Artemis II, ratcheting up the risk. That’s why NASA is waiting a full day before committing Wiseman and his crew to a four-day trip to the moon and four-day journey back.