NASA postpones Artemis 1 rocket launch as engine problem leaves timing of a next attempt uncertain

CAPE CANAVERAL, Florida – NASA postponed its Artemis I launch Monday after issues emerged during countdown, delaying the debut of its towering rocket and its long-awaited mission to the moon.

The agency was slated to launch its Artemis I mission from the Kennedy Space Center during a two-hour launch window that opened at 8:33 a.m. ET, sending the Space Launch System (SLS) rocket and Orion capsule on a more than monthlong journey around the moon.

But NASA was unable to resolve a temperature problem identified with one of the four liquid-fueled engines, discovered with under two hours to go in the countdown.

The uncrewed launch marks the debut of the most powerful rocket ever assembled and kicks off NASA’s long-awaited return to the moon’s surface. It’s the first mission in NASA’s Artemis lunar program, which is expected to land the agency’s astronauts on the moon by its third mission in 2025.

While Artemis I will not carry astronauts, nor land on the moon, the mission is critical to demonstrating that NASA’s monster rocket and deep space capsule can deliver on their promised abilities. Artemis I has been delayed for years, with the program running billions over budget.

NASA has backup launch dates scheduled for Sept. 2 and Sept. 5, but officials during a press conference on Monday afternoon couldn’t say whether the engine issue will be fixed before either of those dates.

“There’s a non-zero chance we’ll have a launch on Friday,” NASA’s Artemis mission manager Mike Sarafin told reporters, before adding “we really need time to look at all the information, all the data.”

NASA’s team is expected to meet on Tuesday afternoon to identify the next steps for Artemis I. If a launch attempt in the next week isn’t possible, the SLS rocket may need to be rolled off the launchpad for what would likely be a lengthy delay.

The possibility of moving the rocket off the launchpad “is getting ahead of our data reviews,” Sarafin said. “If we can resolve this operationally at the pad then there won’t be any need for that.”

Sarafin also noted the engine temperature problem was a known risk, as the agency had not fully completed a fueling test known as a “wet dress rehearsal” after four attempts this year.

The agency also found a hydrogen leak in the engines and a crack in the thermal protection system material that safeguards the core of the rocket during the countdown Monday — though those issues were resolved before the launch was called off for the day.