Sign up for CNN Science’s pop-up newsletter covering NASA’s Artemis II mission, which will take four astronauts on a 10-day journey around the moon and back.

Already in quarantine to avoid germs, Commander Reid Wiseman and his crew will be the first people to launch to the moon since 1972. They will monitor the dress rehearsal from their Houston base before flying to Kennedy Space Center once the rocket is cleared for flight.

NASA initiated the Artemis II wet dress rehearsal countdown at Kennedy Space Center, marking a full launch simulation with propellant loading, countdown holds, and scrub procedures.

NASA is just days away from its first chance to launch Artemis 2, the first astronaut mission to the moon since 1972, and will attempt a critical test for the lunar flight on Monday, Feb. 2. Ahead of the first launch window for Artemis 2,

The launch of Artemis II will be pushed from a possible February window to March at the earliest after a “wet dress rehearsal countdown,” a prelaunch test to fuel the rocket, was terminated because of a liquid hydrogen leak early Tuesday.