NASA declares Artemis 1 moon mission test successful, begins prepping for launch

The most recent Artemis 1 “wet dress rehearsal” wasn’t perfect, but it was good enough to keep the NASA moon mission on course for liftoff a few months from now.

Artemis 1’s Space Launch System (SLS) rocket and Orion capsule wrapped up the wet dress — a roughly 50-hour series of fueling tests and countdown simulations — on Monday (June 20). Mission team members noticed a hydrogen leak during fueling operations, but they have now decided that it wasn’t serious enough to require a do-over.

“NASA has reviewed the data from the rehearsal and determined the testing campaign is complete. The agency will roll SLS and Orion back to the Vehicle Assembly Building (VAB) at Kennedy next week to prepare the rocket and spacecraft for launch and repair a leak detected during the most recent rehearsal,” agency officials wrote in an update today (opens in new tab) (June 23). (“Kennedy” is NASA’s Kennedy Space Center in Florida, or KSC for short.)

Related: NASA’s Artemis 1 moon mission explained in photos

“NASA plans to return SLS and Orion to the pad for launch in late August,” they added. “NASA will set a specific target launch date after replacing hardware associated with the leak.”

The coming rollback to the VAB will be the second for the Artemis 1 stack. NASA rolled the SLS and Orion off KSC’s Pad 39B for repairs in late April, after three separate wet-dress fueling attempts earlier in the month were scuttled by technical issues. 

One of those issues was a hydrogen leak, but it was in a different spot than the one that cropped up during the most recent wet dress operations. 

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NASA will discuss the impending rollback, repair work and launch plans during a press conference tomorrow (June 24) at 11 a.m. EDT (1500 GMT), agency officials said in today’s update. You can watch that press conference here at, courtesy of NASA.

Artemis 1 will be the first mission for the SLS and for NASA’s Artemis program, which aims to establish a sustainable, long-term human presence on the moon by the end of the 2020s. Artemis 1 will send an uncrewed Orion on a roughly month-long trip around the moon, potentially paving the way for a first crewed Artemis flight in 2024 and a crewed lunar landing a year or two later.

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).  

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