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

CAPE CANAVERAL, Fla. – NASA delayed the launch of Artemis I on Monday after problems arose during the countdown, delaying the towering rocket’s debut and its long-awaited mission to the moon.

The agency was scheduled to launch its Artemis I mission from 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 month-long journey around the moon.

But NASA has been unable to resolve a temperature problem identified with one of the four liquid-propellant engines found less than two hours before the countdown.

The unmanned launch marked the debut of the most powerful rocket ever assembled and ushered in NASA’s long-awaited return to the lunar surface. It is 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.

Although Artemis I will not carry astronauts or land on the moon, the mission is critical to demonstrating that NASA’s monster rocket and deep space capsule can achieve their promised capabilities. Artemis I has been delayed for years, with the program billions over budget.

NASA has backup launch dates set for Sept. 2 and Sept. 5, but officials at a news conference Monday afternoon could not say whether the engine problem would 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.”

The NASA team is expected to meet Tuesday afternoon to determine the next steps for Artemis I. If a launch attempt next week is not possible, the SLS rocket may have to be moved off the launch pad for what would likely be be a long delay.

The possibility of moving the rocket off the launch pad “precedes our data reviews,” Sarafin said. “If we can resolve this operationally at the site, then there will be no need for it.”

Sarafin also noted that the engine temperature issue is a known risk because the agency has 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 material of the thermal protection system that protects the rocket’s core during Monday’s countdown — although those problems were resolved before the launch was canceled for the day.