NASA aims for Artemis launch attempt on Saturday after reviewing rocket engine problem

NASA announced it will make another attempt to launch the Artemis I lunar mission on Saturday, after calling off the launch on Monday due to an engine issue.

The space agency is working toward the debut of its Space Launch System (SLS) rocket and Orion capsule, for what would be a more than month-long journey around the moon.

On Monday, NASA was unable to resolve a temperature problem identified with one of the rocket’s four liquid-fueled engines, discovered with under two hours to go in the countdown. NASA’s manager of the SLS program John Honeycutt said during a press conference on Tuesday that the agency believes the engine issue was due to a faulty sensor, given a data analysis that showed propellant was flowing as expected.

Honeycutt noted that the rocket’s technical team is continuing to review the data and still needs to “polish up on our plan” for making a Saturday launch possible. If NASA needs to roll SLS off the launchpad to get access to the engine sensor, that would likely mean a delay of weeks or months before another launch attempt.

“Replacing the sensor at the launchpad would be tricky,” Honeycutt said.

NASA’s Artemis I mission manager Mike Sarafin said that the team will change the procedure of loading propellant into the rocket, and will start trying to chill the engine to the optimal temperature earlier during the countdown.

Notably, weather remains a concern for whether NASA can attempt the launch on Saturday, according to Space Force weather launch officer Mark Burger.

“The probability of weather violation at any point in the countdown still looks to me rather high,” Burger said during the press conference.

NASA said a two-hour long launch window opens at 2:17 p.m. ET on Saturday, meaning it could liftoff any time between then and 4:17 p.m. Due to the length of the launch window, Burger added that “I still think we have a pretty good opportunity”, despite a roughly 60% forecast that weather would prevent the rocket from launching.

The uncrewed flight is set to be the first of the agency’s most powerful rocket ever assembled and kicks off NASA’s long-awaited return to the moon’s surface. It marks the beginning of 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.