Threatening weather will force NASA to send the Space Launch System (SLS) rocket from its currently precarious position on the launchpad back to the Vehicle Assembly Building for safekeeping. The move will delay the agency’s highly anticipated launch of its Artemis I mission around the Moon.

NASA made the announcement this morning as Hurricane Ian barrels toward Florida. The storm is expected to intensify rapidly today, becoming a major hurricane tonight or early Tuesday morning as it passes by Cuba. Ian could bring “life-threatening storm surge, hurricane-force winds, and heavy rainfall” to western Florida and the Florida Panhandle by the middle of the week, the National Hurricane Center warned this morning. Both President Joe Biden and Governor Ron DeSantis declared a state of emergency for Florida over the weekend.

On Saturday, NASA called off the Artemis I launch that that was planned for tomorrow. At the time, the agency was still unsure whether it should leave the rocket on the launchpad in the hopes that the rocket might be able to take off on its backup date, October 2nd. Today’s decision to roll the rocket back to the Vehicle Assembly Building probably means that plan is scrapped, too. The team has not officially given up on the October 2nd date or announced another possible launch date yet, but Artemis I might now have to wait until November for another launch window.

The highly anticipated launch is supposed to send the uncrewed Orion spacecraft looping around the Moon. It’s a test mission to ensure that the spacecraft can safely carry astronauts to the Moon and back and will mark the SLS’s first trip to space. The Artemis I launch for SLS and Orion is a major step in NASA’s plans to bring the first woman to the Moon.

But before Hurricane Ian came into the picture, the Artemis I launch was already delayed. Two previous launch attempts in late August and early September were scrubbed because of technical problems.

Now, NASA plans to begin moving the rocket back to the Vehicle Assembly Building at 11PM ET tonight. They’re trying to time it so that weather during the rollback meets certain criteria. Among them, they don’t want to be rolling back when peak winds hit more than 40 knots or if there’s more than a 10 percent chance of lightning within 20 nautical miles of the launch area. The rollback itself will take many hours to complete.

“Managers met Monday morning and made the decision based on the latest weather predictions associated with Hurricane Ian, after additional data gathered overnight did not show improving expected conditions for the Kennedy Space Center area. The decision allows time for employees to address the needs of their families and protect the integrated rocket and spacecraft system,” the agency said in a blog post.