Just hours before takeoff on Monday morning, Artemis I, the first mission in NASA's ambitious plan to send people back to the moon, experienced an engine failure, postponing the launch.

Currently, the space agency is considering a backup opportunity that opens this Friday, Sept. 2, at 9:48 a.m. PT. However, there is still some uncertainty in that regard.

"To summarize, we held at T-minus 40 minutes and counting after the team was unable to get past an engine bleed that didn't show the right temperature once they got into the engine bleed test," NASA said.

The launch crew has the option to launch on September 2 depending on what happens with this engine, but we must wait for a decision because the launch director has ultimately called a scrub for the day.

As the team takes a well-earned break after a busy morning, Artemis mission manager Mike Sarafin stressed that it is difficult to predict what will happen to Artemis I until a formal meeting discussing Monday's events takes place, which is scheduled for Tuesday.

Simply put, Sarafin said there is a "non-zero chance" that operations will resume on Friday, as well as a chance that the rocket will be hauled back off the launch pad for a closer inspection. "If we can resolve this operationally out of the pad, there won't be any need for that. And if we can resolve this operationally out at the pad in the next 48 hours; 72 hours, Friday's definitely in play," Sarafin said. "We need the team to digest what we've learned and we'll take it from there," he continued.

As the rocket's boosters were being fueled with liquid oxygen, NASA engineers observed that engine 3 was "not properly being conditioned through the bleed process," which is intended to allow the engines to chill to the proper temperature by releasing a small quantity of fuel. It wasn't working.

After spending about an hour attempting to fix the engine 3 bleed issue, the team met with launch director Charlie Blackwell-Thompson to talk about the next steps. "Right now, the indications don't point to an engine problem," Sarafin said, meaning the setback likely isn't tied to the engine interface itself. "It's in the bleed system that thermally conditions the engines."

The launch of Artemis I was nonetheless scrubbed.

After the delay was made public on Monday, NASA Administrator Bill Nelson remarked, "It's just part of the space business - and particularly a test flight."

"We are stressing and testing this rocket and spacecraft in a way that you would never do it with the human crew on board. That's the purpose of a test flight," he added.