NASA on Monday delayed the launch of the Space Launch System (SLS) rocket from the Kennedy Space Center in Cape Canaveral, Fla., because one of the rocket’s engines failed to condition to the correct temperature.
The next available time for the launch is on Friday.
The highly anticipated launch, part of the ambitious Artemis program, will serve as a key test for the SLS and the Orion exploration spacecraft, which NASA plans to send more than 40,000 miles past the moon on an unmanned test flight. It’s the first in a series of integrated tests to eventually send astronauts back to the moon in 2025 or 2026.
NASA first reported the issue with engine No. 3 around 6:23 a.m. after it failed to properly condition to a set temperature. Launch controllers condition engines by increasing pressure on stage tanks in order to bleed some cryogenic propellant and get them to a proper temperature range for startup.
NASA officials said the SLS rocket’s engine bleed could not be remedied in time for a launch today, but the rocket will remain in its current configuration. The rocket is in a safe and stable condition.
Engineers are currently assessing a plan and gathering data to understand why it did not bleed properly.
Launch controllers also struggled with other issues ahead of the launch, including a hydrogen leak and a small delay caused by lightning, but those issues were eventually resolved.
NASA officials will hold a press conference Monday afternoon to discuss what happened and the next steps.
NASA Administrator Bill Nelson said the SLS rocket is a “very complicated system” and that “we don’t launch until it’s right.”
“It’s just part of the space business,” Nelson said. “You don’t want to light the candle until it’s ready to go.”
The multibillion-dollar Artemis program plans to send astronauts back to the moon for the first time since 1972. NASA has a goal of sending the first person of color and the first woman to the moon.
The Artemis I launch will fly the SLS into space, where it will send Orion past the moon before plummeting back down. Orion will zoom past the moon and make its way back to Earth in a six-week journey.
If all goes according to plan, NASA will send a crewed flight in Orion in 2024 to spend about 10 days in space, before scheduling another mission to land astronauts on the moon’s south pole.
But first, NASA will need to send Orion on its maiden journey.
Nelson said the launch team has done a “perfect job” and is working hard to resolve the engine issue.
“They’ll get to the bottom of it and get it fixed, and then we’ll fly,” he said.
—Updated at 9:42 a.m.