Artemis I, the first in a series of increasingly complex NASA missions aimed at making human exploration of the moon and Mars possible, is not ready to shoot for the stars just yet.

The mission was scheduled for a "wet dress rehearsal" this weekend to allow NASA teams to simulate launch procedures without actually igniting the rocket and sending it into space.

On Sunday, NASA announced that the 5.75-million-pound craft was struggling to pressurize its mobile launcher. That process is crucial to keeping hazardous gases from disturbing the rocket as it is pumped full of 700,000 gallons of cryogenic fuel.

In a media briefing Sunday evening, Launch Director Charlie Blackwell-Thompson and Mission Manager Michael Serafin said they were confident that a fix could be implemented in time to resume tanking operations Monday morning, April 4.

"The team is prepared for this," assured Artemis Mission Manager Michael Serafin, "They've demonstrated incredible discipline and toughness and I'm confident we're going to get there soon. [We] just need to get the time to do that."

Despite four confirmed lightning strikes, things were looking good for the mission as of Sunday morning. Though running an hour behind schedule, teams were approved to begin tanking the rocket once meteorologists confirmed that there were no weather violations.

Blackwell-Thompson and Serafin confirmed that the lightning strikes had no connection to the malfunctioning of the fans used to pressurize the mobile launcher.

An official launch date for Artemis I has not been scheduled and is dependent on the success of this dress rehearsal. A lot is riding on this mission, as the rocket is reportedly the most expensive ever built.

There are no astronauts aboard Artemis I, but its launch will prepare NASA to send a human crew into space on the more complex follow-up mission Artemis II.