CAPE CANAVERAL—With preparations at Kennedy Space Center Launch Complex 39B proceeding smoothly, NASA on Jan. 26 said it was re-targeting the practice launch countdown for its Artemis II lunar flyby mission to no sooner than Jan. 31, two days earlier than planned.

Following the test, during which the Space Launch System (SLS) rocket will be fueled with more than 700,000 gal. of liquid oxygen and liquid hydrogen, NASA will assess if the 10-day Artemis II mission can lift off between Feb. 6-11, the first launch window of the year.

Proactively, the four-member Artemis II crew began a medical quarantine Jan. 23 in Houston.

"The wet dress rehearsal will test the launch team’s ability to hold, resume and recycle to several different times in the final 10 min. of the countdown, " NASA wrote in a mission update posted on its website. 

"The rehearsal will count down to a simulated launch at 9 p.m. EST, but could run to approximately 1 a.m. if needed," it added.

NASA’s second SLS heavy-lift rocket, topped with an Orion deep-space capsule, was rolled out to the launchpad Jan. 17, setting the stage for the wet dress rehearsal and launch of the first crewed flight into deep space in more than 50 years.