CAPE CANAVERAL, Fla. (AP) — NASA's giant new moon rocket moved to the launch pad Saturday in preparation for astronauts' first lunar fly-around in more than half a century.

The out-and-back trip could blast off as early as February.

The 322-foot (98-meter) rocket began its 1-mph (1.6-kph) creep from Kennedy Space Center's Vehicle Assembly Building at daybreak. The 4-mile (6-kilometer) trek took until nightfall.

Thousands of space center workers and their families gathered in the predawn chill to witness the long-awaited event, delayed for years. They huddled together ahead of the Space Launch System rocket's exit from the building, built in the 1960s to accommodate the Saturn V rockets that sent 24 astronauts to the moon during the Apollo program. The cheering crowd was led by NASA's new administrator Jared Isaacman and all four astronauts assigned to the mission.

"What a great day to be here," said Reid Wiseman, the crew commander. "It is awe-inspiring."

Weighing in at 11 million pounds (5 million kilograms), the Space Launch System rocket and Orion crew capsule on top made the move aboard a massive transporter that was used during the Apollo and shuttle eras. It was upgraded for the SLS rocket's extra heft.

The first and only other SLS launch — which sent an empty Orion capsule into orbit around the moon — took place back in November 2022.

"This one feels a lot different, putting crew on the rocket and taking the crew around the moon," NASA's John Honeycutt said on the eve of the rocket's rollout.

Heat shield damage and other capsule problems during the initial test flight required extensive analyses and tests, pushing back this first crew moonshot until now. The astronauts won't orbit the moon or even land on it. That giant leap will take come on the third flight in the Artemis lineup a few years from now.

Wiseman, pilot Victor Glover and Christina Koch — longtime NASA astronauts with spaceflight experience — will be joined on the 10-day mission by Canadian astronaut Jeremy Hansen, a former fighter pilot awaiting his first rocket ride.

They will be the first people to fly to the moon since Apollo 17's Gene Cernan and Harrison Schmitt closed out the triumphant lunar-landing program in 1972. Twelve astronauts strolled the lunar surface, beginning with Neil Armstrong and Buzz Aldrin in 1969. Only four moonwalkers are still alive; Aldrin, the oldest, turns 96 on Tuesday.

"They are so fired up that we are headed back to the moon," Wiseman said. "They just want to see humans as far away from Earth as possible discovering the unknown."

NASA is waiting to conduct a fueling test of the SLS rocket on the pad in early February before confirming a launch date.

"We've, I think, zero intention of communicating an actual launch date" until completing the fueling demo, Isaacman told reporters.

The space agency has only five days to launch in the first half of February before bumping into March.