Artemis I launch updates: launch scrubbed after reoccurring liquid hydrogen leak

Vice President Kamala Harris praised the NASA team behind the Artemis I mission after the launch had to be scrubbed Monday due to an engine problem.

Harris and second gentleman Doug Emhoff had been visiting the Kennedy Space Center before the launch was postponed.

The scrubbed launch was "about showing the great work that happens here," Harris told reporters.

"These exceptional public servants, these exceptional skilled professionals who have the ability to see what is possible and what has never been done before. How exciting is that?" she said.

According to a White House official, Harris and Emhoff will continue with their visit under a revised itinerary.

"She met with astronauts at NASA Operations Support Building II and will proceed to a tour of Artemis II and Artemis III hardware as planned. The Vice President will gaggle following the tour and then depart," the official said.

-ABC News' Benjamin Gittleson

NASA Administrator Bill Nelson defended the scrubbing of the Artemis I launch, saying the launch shouldn't take place until the team is sure it's ready.

"We don't launch until it's right," he said during an interview on NASA TV Monday morning.

"There are certain guidelines. And I think it's just illustrative that this is a very complicated machine, a very complicated system, and all those things have to work, and you don't want to light the candle until it's ready to go."

Nelson said the engineers will continue to "stress" and "test" the rocket to make sure it's ready by the next attempt, which is Sept. 2.

Earlier in the day, Nelson had welcomed several Biden administration officials, including Vice President Kamala Harris and second gentleman Doug Emhoff, to the Kennedy Space Center ahead of the launch.

He said the vice president has been briefed and the White House will continue to receive regular updates.

NASA announced a few minutes after Artemis I was initially scheduled to lift off that the launch has been scrubbed.

Engineers said the problem came from a liquid hydrogen line that was not chilled enough inside one of the rocket’s four core-stage engines, which needs to occur before they can be ignited.

The next attempt will occur on Sept. 2.

Artemis I will likely not be launching at 8:33 a.m. ET as originally planned after NASA ran into several delays in its preparation to send it into space.

The process of tanking, which includes filling the rocket's core stage with liquid oxygen and liquid hydrogen, was delayed due to some passing storms and lightning in the area, NASA said.

Moreover, a leak was discovered in the hydrogen fuel line, which NASA quickly resolved. The leak concentration was “at an acceptable level,” NASA said.

Engineers also discovered a potential crack in the inner stage flange, which connects two of the rocket's cylinders.

The countdown clock is currently paused at T-40 and the launch can go as late as 10:33 a.m. ET If that window passes, the next attempt at launch will be Sept. 2