Artemis I: NASA scrubs its first launch attempt of the Space Launch System

NASA postponed the first launch attempt of its Space Launch System.

Though successful rocket launches are never a guarantee, it is a significant setback for a program that has faced criticism for going wildly over budget and for numerous delays over the years.

The launch director halted the attempt at approximately 8:34 a.m. EDT. According to NASA, The launch was scrubbed due to an issue that came to light with RS-25 engine number 3 during tanking operations.

"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,” the space agency wrote in a statement.

NASA’s SLS may launch on Friday

During a live broadcast, NASA mentioned that they weren’t able to pre-empt or troubleshoot the engine bleed issue during their wet dress rehearsal in June.

NASA faces intense scrutiny as SLS has cost the U.S. public $23 billion to date, and it was originally meant to launch in 2016. It is also running on non-reusable technology, which could cost an "unsustainable" $4.1 billion per launch, according to NASA's own Inspector General. Meanwhile, SpaceX CEO Elon Musk recently announced that a reusable Starship rocket mission could cost a comparatively low $1 million.

Still, the next Artemis I mission attempt should be just around the corner, as NASA has another launch window set for Friday, September 2. Once SLS does launch, it will be the first mission in NASA’s Artemis program, which aims to send the first astronauts back to the moon since Apollo 17 in 1972. That lunar landing mission, Artemis III, will send the first woman and first person of color to the moon.

It's currently unclear, however, whether the launch will have to be pushed back further than September 2 or not. NASA said it will hold a press conference later today where it should confirm whether it will go ahead with the Friday launch attempt. Alternatively, SLS may have to undergo maintenance on the launch pad or even be sent back to the Vehicle Assembly Building (VAB) at Cape Canaveral. This process takes roughly a day to complete.

NASA Administrator: You don’t ‘light the candle until it’s ready’

During the NASA TV broadcast, NASA Administrator Bill Nelson said, “you don’t want to light the candle until it’s ready to go.” He also cited “a problem with the gases during the engine bleed on one of the engines.” Nelson also mentioned he was present for a Space Shuttle mission that had to scrub four times before a “flawless mission.”

“We are stressing and testing this spacecraft in a way you would never do with human crew onboard,” he continued. “And that’s the purpose of this test flight.”

Jonathan McDowell, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian, wrote on Twitter that NASA might need more time to figure out the intricacies of its complex launch system. “There's the rocket you thought you designed and the rocket you actually built,” he wrote. “It takes a while to learn how the rocket you actually built works. A few more wet dress rehearsals masquerading as launch attempts may be in the cards.”

Around the time the launch was scrubbed, it was raining at launch pad 39B, Cape Canaveral, Florida, where SLS sits awaiting liftoff. That means that, even if the engine bleed issue had been resolved, we might not have seen SLS soar to orbit today due to weather conditions. A lot will have to go right for the launch to go ahead on Friday. Look out for more updates later today.

This was a breaking news story, and it was updated as more information emerged.