NASA sets new date for Artemis I launch to the moon after delays due to engine issues

• The first launch of NASA's Space Launch System rocket was delayed on Monday because of an engine issue.
• NASA says the next launch opportunity is Saturday, September 3.

After a long-awaited run-up to the day NASA's moon rocket was supposed to blast off from Earth, the mission's launch was delayed on Monday due to an engine issue.

But now NASA has a new target launch window for Artemis I: Saturday, September 3 at 2:17 p.m. ET.

"We are setting up for a launch attempt on September 3 and we're comfortable with our risk posture," Michael Sarafin, Artemis mission manager, said at a Thursday press briefing. "That said, there's no guarantee that we're going to get off on Saturday. But we're going to try."

Just 40 minutes before liftoff, NASA froze the launch countdown to inspect a suspicious difference in temperature on one of the RS-25 engines as they all went through the routine process of bleeding hydrogen. Engine number 3 wasn't matching its three counterparts.

After more than an hour of holding for further information, the launch director finally called off the launch attempt at 8:35 a.m. ET.

"We don't launch until it's right," NASA Administrator Bill Nelson said on NASA's livestream shortly afterwards. "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."

The rocket, called the Space Launch System (SLS), was partially filled with fuel at the time of the issue. NASA said the rocket and its Orion spaceship were stable, so engineers were maintaining that partially fueled state Monday morning in order to gather more data on the engine issue.

In a blog post after the scrub, NASA said that "launch controllers were continuing to evaluate why a bleed test to get the RS-25 engines on the bottom of the core stage to the proper temperature range for liftoff was not successful, and ran out of time in the two-hour launch window."

NASA had previously intended to test the engine bleed during a launch rehearsal in June, but was unable to do so because of a hydrogen leak.

In the meantime, the rocket will remain on Launchpad 39B at NASA's Kennedy Space Center until Saturday. Weather during Saturday's launch window "is a 60% go for launch," Melody Levin, a meteorologist at NASA, said at a briefing on Thursday. "The bottom line is that I don't expect weather to be a showstopper."

If the launch does not happen Saturday, the next two-hour window will be on Monday, September 5.

17 years of work, $50 billion, and NASA's return to the moon hang in the balance

More than 100,000 visitors were expected to gather near the space center in Cape Canaveral, Florida, to view the inaugural launch of the new moon rocket and spaceship.

NASA has spent 17 years and an estimated $50 billion developing the SLS rocket and its Orion spaceship, according to The Planetary Society.

During the Artemis I mission, NASA aims to fly the Orion crew capsule all the way around the moon — farther than any spacecraft built for humans has ever flown — before heading back for a splashdown in the Pacific Ocean in October.

There won't be people on board during the Artemis I launch. But if the spaceship successfully completes its mission, NASA plans to put astronauts in the Orion module for another trip around the moon, during the Artemis II mission, then land them on the lunar surface as part of Artemis III, in 2025. That would be humans' first return to the moon since 1972.

This story has been updated with new information. It was originally published on August 29, 2022.