NASA delays Artemis I launch to the moon due to engine issues

  • The first launch of NASA’s Space Launch System rocket was delayed on Monday because of an engine issue.
  • NASA’s next launch opportunity is Friday, September 2, but it’s not clear if the engine issue can be resolved by then.
  • Artemis I is a 42-day test flight that will set the stage for future Artemis missions with astronauts.

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 due to an engine issue.

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.”

engineers in hard hats gather underneath giant rocket stage on its side with four engines in the air

The Space Launch System core stage (RS-25 engines circled in blue) in the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida on June 10, 2021.
NASA/Glenn Benson

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.

The space agency says the earliest opportunity to launch will be on Friday, September 2 at 12:48 p.m. ET  — which was one of the backup launch windows in case of technical issues or weather delays. However, engineers will make the decision once they’ve gathered more data about the issue.

“That [date] is available to the launch team, however we will await a determination of what the plan is to go forward, to remedy the engine bleed, and then go from there,” Derrol Nail, NASA spokesperson, said during live commentary on Monday. “We must wait to see what shakes out from their test data.”

In the meantime, the rocket will remain on Launchpad 39B at NASA’s Kennedy Space Center.

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

orange space launch system rocket stands upright against blue sky

NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard, at the Kennedy Space Center in Florida, August 26, 2022.
NASA/Steve Seipel

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.