NASA will soon run a high‑stakes fueling test on its Artemis II rocket, a practice run that must succeed before four astronauts can fly around the moon.

The U.S. space agency inched the 11 million-pound Space Launch System and mobile launcher to a Cape Canaveral, Florida, launchpad on Saturday, Jan. 17. The slow procession of the 322-foot rocket, topped with the Orion spaceship, took 12 hours on the aging crawler-transporter to complete. 

That four-mile trek could mark the first leg of Artemis II, a 10-day journey around the moon and back that will put the spaceship through its paces. The lunar mission will be NASA's first with astronauts —Victor Glover, Christina Koch, Reid Wiseman, and Canada's Jeremy Hansen — in 53 years since Apollo 17. 

The so-called "wet dress rehearsal" will load the mega moon rocket with 700,000 gallons of ultra‑cold liquid oxygen and liquid hydrogen propellants and take the countdown all the way to 29 seconds before liftoff. How this test goes will shape the flight timeline and determine whether launch opportunities in February remain in play.

"We need to get through wet dress, we need to see what lessons we learn as a result of that, and that will ultimately lay out our path toward launch," Artemis Launch Director Charlie Blackwell‑Thompson said. "With a wet dress that is without significant issues, if everything goes to plan, then certainly there are opportunities within February that could be achievable." 

NASA's mega moon rocket emerges from its massive warehouse at Kennedy Space Center in Cape Canaveral, Florida, on Jan. 17, 2026. Credit: NASA / Joel Kowsky

When is the wet dress rehearsal? 

The 322-foot rocket, taller than the Statue of Liberty, rolls past the firing room on its way to the launchpad in Cape Canaveral, Florida, on Jan. 17, 2026. Credit: NASA / Aubrey Gemignan

During the test, teams will fill the rocket and rehearse every major step of launch‑day fueling. Controllers will run through all countdown procedures, including the final "terminal count," then stop on purpose at T‑29 seconds. NASA is targeting Feb. 2 for the crucial exercise, though that could change, depending on preparations. 

"We'll review the data,"  said Blackwell‑Thompson, "then we'll set up for our launch attempt." 

The results will determine whether NASA will hit its soonest launch window, which opens Feb. 6.

NASA's crawler-transporter carries the 11-million-pound rocket stack and mobile launcher to the launchpad at Kennedy Space Center on Jan. 17, 2026. Credit: NASA / Aubrey Gemignani

Artemis II builds on lessons from the uncrewed maiden voyage in 2022, which needed several tries to complete fueling. Engineers adjusted how they load liquid oxygen after seeing temperature issues and modified hardware after hydrogen leaks were discovered in the connection between the ground systems and the rocket. They also changed and cryogenically tested a key valve that caused trouble during the final uncrewed countdown.

Since Artemis I, the Kennedy Space Center has revised procedures and upgraded hardware as part of the Artemis II plan.

The mega moon rocket traverses 4 miles to get to the launchpad for a wet dress rehearsal at Kennedy Space Center in Cape Canaveral, Florida, on Jan. 17, 2026. Credit: NASA / Ben Smegelsky

From left, NASA administrator Jared Isaacman, Canadian astronaut Jeremy Hansen, Christina Koch, pilot Victor Glover, and Artemis II commander Reid Wiseman take questions from reporters as the mega moon rocket rolls behind them to the launchpad in Cape Canaveral, Florida, on Jan. 17, 2026. Credit: NASA / Kim Shiflett

When will Artemis II launch?

After 12 hours of crawling, the rocket reaches launchpad 39B at Kennedy Space Center in Cape Canaveral, Florida, after 6 p.m. ET on Jan. 17, 2026. Credit: NASA / Brandon Hancock

Once the wet dress rehearsal ends, engineers will pore over the performance of the rocket, the Orion spacecraft, and the ground systems. Only if the data looks clean will the mission managers move on to setting a specific launch date. 

NASA officials have rejected any characterization that the team has "launch fever" or that preparations have been rushed.

"I've got one job, and it's a safe return of Reid and Victor and Christina and Jeremy. I consider that a duty and a trust," said John Honeycutt, chairperson of the mission management team. "We're going to fly when we're ready."