NASA could launch four astronauts on a mission to fly around the moon as soon as March 6th.

That’s the launch date that the space agency is now working towards following a successful test fueling of its big, 322-foot-tall moon rocket, which is standing on a launch pad at the Kennedy Space Center in Florida.

“This is really getting real,” says Lori Glaze, acting associate administrator of NASA’s exploration systems development mission directorate. “It’s time to get serious and start getting excited.”

But she cautioned that there’s still some pending work that remains to be done out at the launch pad, and officials will have to conduct a multi-day flight readiness review late next week to make sure that every aspect of the mission is truly ready to go.

“We need to successfully navigate all of those, but assuming that happens, it puts us in a very good position to target March 6th,” she says, noting that the flight readiness review will be “extensive and detailed.”

The Artemis II test flight will send four astronauts on an approximately 600,000-mile trip around the moon and back. It will mark the first time that people have ventured to the moon since the final Apollo lunar mission in 1972.

When NASA workers first tested out fueling the rocket earlier this month, they encountered problems like a liquid hydrogen leak. Swapping out some seals and other work seems to have fixed these issues, according to officials who say that the latest countdown dress rehearsal went smoothly, despite glitches such as a loss of ground communications in the Launch Control Center that forced workers to temporarily use backups.

Members of the Artemis II crew — NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen — are starting their roughly two-week quarantine to limit their exposure to illnesses before their flight.

Glaze says she spoke to several of the astronauts during the recent test fueling, as they were in Florida to observe the preparations. “They’re all very, very excited,” she says. “They are really getting a lot of anticipation for a potential launch in March.”