Watch NASA roll Artemis 2 moon rocket off launch pad on Feb. 25 to deal with glitch

NASA will roll its Artemis 2 moon rocket off the launch pad on Wednesday (Feb. 25) to deal with a glitch, and you can watch the long trek live.

Artemis 2's Space Launch System (SLS) rocket, topped by the Orion spacecraft, will start rolling off Kennedy Space Center's (KSC) Launch Pad 39B and back to the cavernous Vehicle Assembly Building (VAB) on Wednesday at around 9 a.m. EST (1400 GMT), if all goes according to plan.

The four-mile (6.4-kilometer) trek, made atop NASA's huge Crawler-Transporter 2 vehicle, may take up to 12 hours. You can watch it all here at Space.com, courtesy of NASA, or directly via the space agency.

Artemis 2 rolled out to Pad 39B on Jan. 17. Two weeks later, mission team members conducted a wet dress rehearsal (WDR), a two-day-long practice run of the procedures that precede launch.

A leak of liquid hydrogen (LH2) propellant ended that WDR a few hours early on Feb. 2. The Artemis 2 team swapped out some seals in the trouble spot ahead of a second WDR, which the mission successfully completed on Feb. 19.

Indeed, things went so well on that WDR that NASA began gearing up for a March 6 launch attempt. But a problem popped up overnight from Feb. 20 to Feb. 21: an interruption of helium flow in the SLS' upper stage.

This was a pretty big deal. Helium pressurizes SLS' propellant tanks, which together hold about 730,000 gallons (2.76 million liters) of LH2 and liquid oxygen. So, on Sunday (Feb. 22), NASA announced it will roll back to the VAB to troubleshoot the helium issue.

This will take the March launch window out of consideration for Artemis 2, which isn't a big surprise; it ran only through March 11. The next window opens on April 1 and also features opportunities between April 3-6 and on April 30.

Artemis 2 will send four astronauts — NASA's Reid Wiseman, Victor Glover and Christina Koch, and the Canadian Space Agency's Jeremy Hansen — on a roughly 10-day trip around the moon and back to Earth.

It will be the first crewed trip beyond low Earth orbit since the Apollo 17 moon-landing mission in 1972.