NASA completes the dress rehearsal for the SLS. Dress rehearsal for the SLS is over! Space Launch System, or SLS, completed a launch dress rehearsal today (June 20, 2022) on the agency's third launch attempt following its successful rollout to historic Launch Pad 39B at Kennedy Space Center on June 10, 2022. NASA will hold a press conference tomorrow morning to inform the media about the results of the rocket test.

Artemis will be launched by the SLS rocket. Earlier this week, NASA technicians put the rocket to the test. NASA has been practicing every step up until the final ignition of the main engines, including pushing every button and flipping every switch, as they prepare for the launch of the Artemis 1 rocket this summer.

It was NASA's third attempt to finish the Wet Dress Rehearsal. Moonship shakedowns were unsuccessful on two prior occasions - one in December 2020 and a second just a few months later in March 2022.

The Orion spacecraft will make an uncrewed trip around the moon once the SLS - NASA's most powerful vehicle to date - is deemed safe for flight. The uncrewed trip will mark a crucial step toward humanity's return to the lunar surface and eventually to Mars. Artemis 2 will be the first crewed mission in 2024. Astronauts will return to the moon with Artemis 3 no earlier than 2025, marking the first trip in 50 years. Today's Wet Dress Rehearsal is critical to the Artemis launch schedule.

The two prior attempts to prepare the ship for the flight were both cut short of completing the full WDR, although NASA remains confident in its latest and most powerful manned space vehicle. A problem with a hydrogen leak in one of the ship's umbilical cables caused NASA to change its schedule for today's successful testing. Watchers of the WDR milestones were cautioned that the listed times were approximate, and delays could occur:

A freeze to address the hydrogen leak - Mission Control eventually decided to ignore the computer's warnings - resulted in the countdown being delayed, but not halted, and the schedule was put back by several hours. After the launch director and the mission management team chair gave the green light to fill the SLS's fuel tanks, the fuel tanks were filled. The entire fuel load was supposed to take five hours to load.

A built-in hold of 30 minutes halted the countdown for the final NASA test director briefing. Each launch team division then voted on 'go' or 'no-go'. The WDR Run 1 countdown resumed at T-10 minutes and counting after all lights on all control boards were lit and the leak issue was addressed. As the vehicle switched from internal to external power, the Orion ascent pyros were armed. Exactly seven minutes after the ground launch sequencer sent the 'cutoff' command, the countdown ended at 33 seconds.