NASA will roll its Artemis 1 moon rocket off the launch pad today (April 25), and you can watch the action live.
The huge Artemis 1 stack — a Space Launch System (SLS) rocket with an Orion crew capsule on top — is scheduled to roll off Pad 39B at NASA's Kennedy Space Center (KSC) in Florida today at about 5:30 p.m. EDT (2130 GMT). Watch it live here at Space.com, courtesy of KSC, or directly via the center (opens in new tab).
Artemis 1 rolled out to Pad 39B from KSC's Vehicle Assembly Building (VAB) on March 17 to prepare for its "wet dress rehearsal," a crucial series of tests designed to get the mission ready for liftoff. That procedure, which culminates in the fueling of the SLS and the performance of several simulated launch countdowns, began on April 1 and was supposed to end on April 3.
Live updates: NASA's Artemis 1 moon mission
Related: NASA's Artemis 1 moon mission explained in photos
But Artemis 1 encountered several problems during the wet dress that complicated and delayed things — namely, a faulty valve in the mission's mobile launch tower and a hydrogen leak in one of the lines connecting the tower to the rocket. The April 8 launch of the private Ax-1 astronaut mission from KSC's Pad 39A also complicated things, causing Artemis 1 to stand down for a spell.
Mission team members ultimately decided to roll Artemis 1 back to the VAB to address these issues. After those fixes are made, the stack will head back out to Pad 39B and finish the wet dress rehearsal, NASA officials have said.
The rollback, performed by NASA's huge crawler-transporter 2 vehicle, will begin today but almost certainly extend into tomorrow (April 26); the mid-March rollout to Pad 39B took nearly 11 hours. It's about 4 miles (6.4 km) from Pad 39B to the VAB.
Artemis 1, the first mission in NASA's Artemis program of lunar exploration, will send an uncrewed Orion on a roughly month-long journey around the moon. NASA won't set a target launch date for Artemis 1 until the wet dress is complete and the data analyzed. The earliest possible liftoff date is likely sometime in July.
Mike Wall is the author of "Out There (opens in new tab)" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall (opens in new tab). Follow us on Twitter @Spacedotcom (opens in new tab) or on Facebook (opens in new tab).