Washington, Jun 21 (IANS): After halting Artemis 1 moon rocket's "wet dress rehearsal" several times, NASA has successfully completed the crucial fuelling test of its Space Launch System (SLS) megarocket.

The Artemis 1 wet dress rehearsal ended at 7.37 p.m. EDT on June 20, NASA said in a statement.

"This is the first time the team fully loaded all the SLS rocket's propellant tanks and proceeded into the terminal launch countdown, when many critical activities occurred in rapid succession,a the US space agency.

However, the test did not go smoothly.

During propellant loading operations, the team encountered a hydrogen leak in the quick disconnect that attaches an umbilical from the tail service mast on the mobile launcher to the rocket's core stage.

While the team attempted to fix the leak by warming the quick disconnect and then chilling it back down to realign a seal, their efforts did not fix the issue, NASA said.

The team then intentionally "masked" data associated with the issue to let the countdown continue. During an actual launch countdown, such data would have raised red flags. This change meant a delay, "but they were able to resume with the final 10 minutes of the countdown", NASA said.

"Today's #Artemis I wet dress rehearsal activities concluded after a modified countdown configuration and successfully adding propellant to the rocket. We will review the data and are meeting to discuss next steps," mission officials wrote on Twitter.

The final test is the culmination of months of assembly and testing for SLS and Orion, as well as preparations by launch control and engineering teams, and set the stage for the first Artemis launch.

Artemis 1, was earlier scheduled to launch in late May 2022. However, due to multiple delays in its wet dress rehearsal, the mega moon rocket has been pushed further.

The success of the final test could set the stage for its first launch in August, NASA had indicated earlier.

The uncrewed Artemis I mission is the first flight of the SLS rocket and Orion spacecraft together. Future missions will send people to work in lunar orbit and on the Moon's surface.

With the Artemis missions, NASA will land the first woman and the first person of colour on the Moon and establish long-term exploration in preparation for missions to Mars.