NASA’s Space Launch System is once again standing proud on the launch pad at Kennedy Space Center in Florida. The gigantic rocket is being prepared for its inaugural launch, but the space agency must first succeed at completing a full launch rehearsal, which it has thus fair failed to do.
The Moon rocket rolled out of the Vehicle Assembly Building earlier today to make the four mile (6.4 kilometer) trek to launch pad 39B. SLS reached its destination some eight hours later, arriving at 8:20 a.m. ET, according to NASA. The rocket was then connected to the ground systems in preparation for the tanking test, which is scheduled to happen in about two weeks.
This marks the rocket’s second return to the launch pad, as the NASA ground team experienced three failed attempts to complete a full-fledged wet dress rehearsal in April. NASA says the ground team has resolved the various technical issues that foiled the previous tests, including malfunctioning ventilation fans, a small hydrogen leak, and valve issues.
There’s a lot riding on the success of the 322-foot-tall (98-meter) rocket, the largest NASA has ever built. Its launch will signal the official start to the Artemis era, a series of missions in which NASA will attempt to return humans to the Moon. The program is off to a shaky start, but no one said rocket science was going to be easy.
The first wet dress rehearsal of the SLS rocket was scheduled for April 1, but it was delayed due to technical issues that prevented the crew from loading the rocket with fuel. Before the next test took place on April 11, the team discovered a faulty valve, which led officials to modify the rehearsal, in which only the core stage, and not the upper stage, was to be loaded with cryogenic propellant. The third attempt on April 14 proved to be challenging as well, as the team discovered a leak of liquid hydrogen from the tail service mast umbilical, which connects the base of the mobile launcher to the core stage.
Since then, the rocket has been sitting in the Vehicle Assembly Building as engineers worked to resolve the issues that were noted during the previous wet dress rehearsal attempts. Technicians inside the high bay tightened seals on the umbilical connection in hopes of fixing the hydrogen leak. NASA engineers swapped out the helium valve on the upper stage, which had failed due to rubber debris stuck in the mechanism. They also redesigned the umbilical boot, added leak detectors, and tested the upgraded gaseous nitrogen system, according to Cliff Lanhman, senior vehicle operations manager at NASA, who spoke to reporters during a media briefing on May 27.
The launch of the SLS rocket as part of the Artemis 1 mission (an uncrewed mission to the Moon and back) has already been pushed back from June to no earlier than August. The August launch periods run until August 10 (excluding August 1, 2, and 6) and then from August 23 to September 6 (excluding August 30, 31, and September 1).
Should the upcoming wet dress rehearsal go smoothly, the rocket will once again roll back to the Vehicle Assembly Building for final launch preparations and testing before it will finally lift off and send the Orion capsule on a trip to the Moon and back.
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